Semiconductor Device Test Applications Guide

Semiconductor Device Test Applications Guide
Series 2600A
System SourceMeter®
Instruments
Semiconductor Device Test
Applications Guide
Contains Programming Examples
A
G R E A T E R
M E A S U R E
O F
C O N F I D E N C E
Although this Guide was originally developed as an applications resource for Series 2600 System SourceMeter®
instruments, the application information and sample test scripts provided are equally suitable for use with
Keithley’s newest SMU line, the Series 2600A. To implement any of these applications with the new models,
simply substitute the equivalent new model number for the original, that is, Model 2602A to replace Model
2602, Model 2612A to replace Model 2612, etc.
Table of Contents
Section 1 General Information
1.1
Introduction . . . . . . . . . . . . . . . . . . . . . 1-1
1.2
Hardware Configuration . . . . . . . . . . . . . . . 1-1
1.2.1 System Configuration . . . . . . . . . . . . . 1-1
1.2.2 Remote/Local Sensing Considerations . . . . 1-2
1.3
Common-Emitter Characteristics . . . . . . . . . .
3.3.1 Test Configuration . . . . . . . . . . . . . . .
3.3.2 Measurement Considerations . . . . . . . . .
3.3.3 Example Program 4:
Common-Emitter Characteristics . . . . . . .
3.3.4 Typical Program 4 Results . . . . . . . . . . .
3.3.5 Program 4 Description . . . . . . . . . . . .
3-2
3-3
3-3
3.4
Gummel Plot . . . . . . . . . . . . . . . . . . . . .
3.4.1 Test Configuration . . . . . . . . . . . . . . .
3.4.2 Measurement Considerations . . . . . . . . .
3.4.3 Example Program 5: Gummel Plot . . . . . .
3.4.4 Typical Program 5 Results . . . . . . . . . . .
3.4.5 Program 5 Description . . . . . . . . . . . .
3-3
3-3
3-4
3-4
3-5
3-5
3.5
Current Gain . . . . . . . . . . . . . . . . . . . . .
3.5.1 Gain Calculations . . . . . . . . . . . . . . .
3.5.2 Test Configuration for Search Method . . . .
3.5.3 Measurement Considerations . . . . . . . . .
3.5.4 Example Program 6A: DC Current Gain
Using Search Method . . . . . . . . . . . . .
3.5.5 Typical Program 6A Results . . . . . . . . . .
3.5.6 Program 6A Description . . . . . . . . . . . .
3.5.7 Modifying Program 6A . . . . . . . . . . . .
3.5.8 Configuration for Fast Current Gain Tests . .
3.5.9 Example Program 6B: DC Current Gain
Using Fast Method . . . . . . . . . . . . . . .
3.5.10 Program 6B Description . . . . . . . . . . . .
3.5.11 Example Program 7: AC Current Gain . . . .
3.5.13 Typical Program 7 Results . . . . . . . . . . .
3.5.14 Program 7 Description . . . . . . . . . . . .
3.5.15 Modifying Program 7 . . . . . . . . . . . . .
3-6
3-6
3-6
3-6
Graphing . . . . . . . . . . . . . . . . . . . . . . . 1-2
Section 2 Two-terminal Device Tests
2.1
3.3
Introduction . . . . . . . . . . . . . . . . . . . . . 2-1
2.2 Instrument Connections . . . . . . . . . . . . . . 2-1
2.3
2.4
2.5
Voltage Coefficient Tests of Resistors . . . . . . . 2-1
2.3.1 Test Configuration . . . . . . . . . . . . . . . 2-1
2.3.2 Voltage Coefficient Calculations . . . . . . . . 2-1
2.3.3 Measurement Considerations . . . . . . . . . 2-2
2.3.4 Example Program 1:
Voltage Coefficient Test . . . . . . . . . . . . 2-2
2.3.5 Typical Program 1 Results . . . . . . . . . . . 2-3
2.3.6 Program 1 Description . . . . . . . . . . . . 2-3
Capacitor Leakage Test . . . . . . . . . . . . . . . 2-3
2.4.1 Test Configuration . . . . . . . . . . . . . . . 2-3
2.4.2 Leakage Resistance Calculations . . . . . . . 2-3
2.4.3 Measurement Considerations . . . . . . . . . 2-4
2.4.4 Example Program 2:
Capacitor Leakage Test . . . . . . . . . . . . 2-4
2.4.5 Typical Program 2 Results . . . . . . . . . . . 2-4
2.4.6 Program 2 Description . . . . . . . . . . . . 2-5
Diode Characterization . . . . . . . . . . . . . . . 2-5
2.5.1 Test Configuration . . . . . . . . . . . . . . . 2-5
2.5.2 Measurement Considerations . . . . . . . . . 2-5
2.5.3 Example Program 3:
Diode Characterization . . . . . . . . . . . . 2-5
2.5.4 Typical Program 3 Results . . . . . . . . . . . 2-6
2.5.5 Program 3 Description . . . . . . . . . . . . 2-6
2.5.6 Using Log Sweeps . . . . . . . . . . . . . . . 2-7
2.5.7 Using Pulsed Sweeps . . . . . . . . . . . . . 2-7
3.6
Transistor Leakage Current . . . . . . . . . . . . .
3.6.1 Test Configuration . . . . . . . . . . . . . . .
3.6.2 Example Program 8: ICEO Test . . . . . . . . .
3.6.3 Typical Program 8 Results . . . . . . . . . . .
3.6.4 Program 8 Description . . . . . . . . . . . .
3.6.5 Modifying Program 8 . . . . . . . . . . . . .
3-1
3-2
3-2
3-6
3-7
3-7
3-7
3-8
3-8
3-9
3-9
3-10
3-10
3-10
3-10
3-10
3-11
3-11
3-11
3-12
Section 3 Bipolar Transistor Tests
Section 4 FET Tests
3.1
Introduction . . . . . . . . . . . . . . . . . . . . . 3-1
4.1
3.2
Instrument Connections . . . . . . . . . . . . . . 3-1
4.2 Instrument Connections . . . . . . . . . . . . . . 4-1
Introduction . . . . . . . . . . . . . . . . . . . . . 4-1
4.3
4.4
4.5
Common-Source Characteristics . . . . . . . . . .
4.3.1 Test Configuration . . . . . . . . . . . . . . .
4.3.2 Example Program 9: Common-Source
Characteristics . . . . . . . . . . . . . . . . .
4.3.3 Typical Program 9 Results . . . . . . . . . . .
4.3.4 Program 9 Description . . . . . . . . . . . .
4.3.5 Modifying Program 9 . . . . . . . . . . . . .
Transconductance Tests . . . . . . . . . . . . . . .
4.4.1 Test Configuration . . . . . . . . . . . . . . .
4.4.2 Example Program 10: Transconductance
vs. Gate Voltage Test . . . . . . . . . . . . . .
4.4.3 Typical Program 10 Results . . . . . . . . . .
4.4.4 Program 10 Description . . . . . . . . . . . .
Threshold Tests . . . . . . . . . . . . . . . . . . . .
4.5.1 Search Method Test Configuration . . . . . .
4.5.2 Example Program 11A: Threshold Voltage
Tests Using Search Method . . . . . . . . . .
4.5.3 Program 11A Description . . . . . . . . . . .
4.5.4 Modifying Program 11A . . . . . . . . . . . .
4.5.5 Self-bias Threshold Test Configuration . . . .
4.5.6 Example Program 11B: Self-bias
Threshold Voltage Tests . . . . . . . . . . . .
4.5.7 Program 11B Description . . . . . . . . . . .
4.5.8 Modifying Program 11B . . . . . . . . . . . .
5.3.9 Program 13 Description . . . . . . . . . . . . 5-7
5.3.10 Modifying Program 13 . . . . . . . . . . . . . 5-7
4-1
4-1
4-1
4-2
4-2
4-3
5.4
4-3
4-3
4-4
4-5
4-5
4-6
4-6
4-6
4-7
4-7
4-7
4-8
4-9
4-9
Section 5 Using Substrate Bias
5.1
Introduction . . . . . . . . . . . . . . . . . . . . . 5-1
5.2
Substrate Bias Instrument Connections . . . . . . 5-1
5.2.1 Source-Measure Unit Substrate Bias
Connections and Setup . . . . . . . . . . . . 5-1
5.2.2 Voltage Source Substrate Bias Connections . . 5-2
5.3
Source-Measure Unit Substrate Biasing . . . . . .
5.3.1 Program 12 Test Configuration . . . . . . . .
5.3.2 Example Program 12: Substrate Current
vs. Gate-Source Voltage . . . . . . . . . . . .
5.3.3 Typical Program 12 Results . . . . . . . . . .
5.3.4 Program 12 Description . . . . . . . . . . . .
5.3.5 Modifying Program 12 . . . . . . . . . . . . .
5.3.6 Program 13 Test Configuration . . . . . . . .
5.3.7 Example Program 13: Common-Source
Characteristics with Source-Measure Unit
Substrate Bias . . . . . . . . . . . . . . . . .
5.3.8 Typical Program 13 Results . . . . . . . . . .
BJT Substrate Biasing . . . . . . . . . . . . . . . .
5.4.1 Program 14 Test Configuration . . . . . . . .
5.4.2 Example Program 14: Common-Emitter
Characteristics with a Substrate Bias . . . . .
5.4.3 Typical Program 14 Results . . . . . . . . . .
5.4.4 Program 14 Description . . . . . . . . . . . .
5.4.5 Modifying Program 14 . . . . . . . . . . . . .
5-7
5-7
5-7
5-9
5-9
5-10
Section 6 High Power Tests
6.1
Introduction . . . . . . . . . . . . . . . . . . . . .
6.1.1 Program 15 Test Configuration . . . . . . . .
6.1.2 Example Program 15: High Current
Source and Voltage Measure . . . . . . . . .
6.1.3 Program 15 Description . . . . . . . . . . . .
6-1
6-1
6.2 Instrument Connections . . . . . . . . . . . . . .
6.2.1 Program 16 Test Configuration . . . . . . . .
6.2.2 Example Program 16: High Voltage
Source and Current Measure . . . . . . . . .
6.2.3 Program 16 Description . . . . . . . . . . . .
6-2
6-2
6-1
6-2
6-2
6-3
Appendix A Scripts
Section 2. Two-Terminal Devices . . . . . . . . . . . . .
Program 1. Voltage Coefficient of Resistors . . . . . .
Program 2. Capacitor Leakage Test . . . . . . . . . .
Program 3. Diode Characterization . . . . . . . . . .
Program 3A. Diode Characterization Linear Sweep . .
Program 3B. Diode Characterization Log Sweep . . .
Program 3C. Diode Characterization Pulsed Sweep .
A-1
A-1
A-5
A-8
A-8
A-11
A-14
5-2
5-2
Section 3. Bipolar Transistor Tests . . . . . . . . . . . . . A-19
Program 4. Common-Emitter Characteristics . . . . . A-19
Program 5. Gummel Plot . . . . . . . . . . . . . . . A-24
5-2
5-4
5-4
5-5
5-5
Section 6. High Power Tests . . . . . . . . . . . . . . . .
Program 6. Current Gain . . . . . . . . . . . . . . .
Program 6A. Current Gain (Search Method) . . . . .
Program 6B. Current Gain (Fast Method) . . . . . . .
Program 7. AC Current Gain . . . . . . . . . . . . . .
Program 8. Transistor Leakage (ICEO) . . . . . . . .
5-5
5-7
A-28
A-28
A-28
A-32
A-36
A-39
Section 4. FET Tests . . . . . . . . . . . . . . . . . . . . . A-43
Program 9. Common-Source Characteristics . . . . . A-43
Program 10. Transconductance . . . . . . . . . . . . A-48
Program 11. Threshold . . . . . . . . . . . . . . . . A-52
Program 11A. Threshold (Search) . . . . . . . . . . . A-52
Program 11B. Threshold (Fast) . . . . . . . . . . . . A-56
Section 5. Using Substrate Bias . . . . . . . . . . . . . .
Program 12. Substrate Current vs. Gate-Source
Voltage (FET ISB vs. VGS) . . . . . . . . . . . .
Program 13. Common-Source Characteristics
with Substrate Bias . . . . . . . . . . . . . .
Program 14. Common-Emitter Characteristics
with Substrate Bias . . . . . . . . . . . . . .
A-60
A-60
A-64
A-71
Section 6. High Power Tests . . . . . . . . . . . . . . . . A-78
Program 15. High Current with
Voltage Measurement . . . . . . . . . . . . . A-78
Program 16. High Voltage with
Current Measurement . . . . . . . . . . . . . A-80
List of Illustrations
Section 1 General Information
Section 5 Using Substrate Bias
Figure 1-1. Typical system configuration for applications . . 1-1
Figure 5-1. TSP-Link connections for two instruments . . . .
Figure 5-2. TSP-Link instrument connections . . . . . . . .
Figure 5-3. Program 12 test configuration . . . . . . . . . .
Figure 5-4. Program 12 typical results: ISB vs. VGS . . . . . .
Figure 5-5. Program 13 test configuration . . . . . . . . . .
Figure 5-6. Program 13 typical results: Common-source
characteristics with substrate bias . . . . . . . . . . . .
Figure 5-7. Program 14 test configuration . . . . . . . . . .
Figure 5-8. Program 14 typical results: Common-emitter
characteristics with substrate bias . . . . . . . . . . . .
Section 2 Two-terminal Device Tests
Figure 2-1. Series 2600 two-wire connections
(local sensing) . . . . . . . . . . . . . . . . . . . . . . . 2-1
Figure 2-2. Voltage coefficient test configuration . . . . . . . 2-1
Figure 2-3. Test configuration for capacitor leakage test . . . 2-3
Figure 2-4. Staircase sweep . . . . . . . . . . . . . . . . . . 2-5
Figure 2-5. Test configuration for diode characterization . . 2-5
Figure 2-6. Program 3 results: Diode forward
characteristics . . . . . . . . . . . . . . . . . . . . . . . 2-6
Section 3 Bipolar Transistor Tests
Figure 3-1. Test configuration for common-emitter tests . . .
Figure 3-2. Program 4 results: Common-emitter
characteristics . . . . . . . . . . . . . . . . . . . . . . .
Figure 3-3. Gummel plot test configuration . . . . . . . . .
Figure 3-4. Program 5 results: Gummel plot . . . . . . . . .
Figure 3-5. Test configuration for current gain tests
using search method . . . . . . . . . . . . . . . . . . .
Figure 3-6. Test configuration for fast current gain tests . . .
Figure 3-7. Configuration for ICEO tests . . . . . . . . . . . .
Figure 3-8. Program 8 results: ICEO vs. VCEO . . . . . . . . .
3-1
3-3
3-4
3-5
3-6
3-8
3-11
3-12
Section 4 FET Tests
Figure 4-1. Test configuration for common-source tests . . .
Figure 4-2. Program 9 results: Common-source
characteristics . . . . . . . . . . . . . . . . . . . . . . .
Figure 4-3. Configuration for transductance tests . . . . . .
Figure 4-4. Program 10 results: Transconductance vs. VGS .
Figure 4-5. Program 10 results: Transconductance vs. ID . .
Figure 4-6. Configuration for search method
threshold tests . . . . . . . . . . . . . . . . . . . . . . .
Figure 4-7. Configuration for self-bias threshold tests . . . .
4-2
4-3
4-4
4-5
4-5
4-6
4-8
5-1
5-2
5-3
5-4
5-5
5-6
5-8
5-9
Section 6 High Power Tests
Figure 6-1. High current (SMUs in parallel) . . . . . . . . . 6-1
Figure 6-2. High voltage (SMUs in series) . . . . . . . . . . . 6-2
Appendix A Scripts
Section 1
General Information
1.1 Introduction
The following paragraphs discuss the overall hardware and software configurations of the system necessary to run the example
application programs in this guide.
1.2 Hardware Configuration
1.2.1 System Configuration
Figure 1-1 shows the overall hardware configuration of a typical
test system. The various components in the system perform a
number of functions:
Series 2600 System SourceMeter Instruments: System Source­­
Meter instruments are specialized test instruments capable
of sourcing current and simultaneously measuring voltage, or
sourcing current and simultaneously measuring voltage. A single
Source-Measure Unit (SMU) channel is required when testing twoterminal devices such as resistors or capacitors. Three- and fourterminal devices, such as BJTs and FETs, may require two or more
SMU channels. Dual-channel System SourceMeter instruments,
such as the Models 2602, 2612, and 2636, provide two SMUs in a
half-rack instrument. Their ease of programming, flexible expansion, and wide coverage of source/measure signal levels make
them ideal for testing a wide array of discrete components. Before
starting, make sure the instrument you are using has the source
and measurement ranges that will fit your testing specifications.
Test fixture: A test fixture can be used for an external test circuit.
The test fixture can be a metal or nonmetallic enclosure, and is
typically equipped with a lid. The test circuit is mounted inside
the test fixture. When hazardous voltages (>30Vrms, 42Vpeak)
will be present, the test fixture must have the following safety
requirements:
CPU
w/GPIB
GPIB
Cable
Series 2600
System
SourceMeter
Output
HI
DUT
Output
LO
Figure 1-1. Typical system configuration for applications
WARNING
To provide protection from shock hazards, an enclosure should be provided that surrounds all live
parts. Nonmetallic enclosures must be constructed
of materials suitably rated for flammability and
the voltage and temperature requirements of the
test circuit. For metallic enclosures, the test fixture
chassis must be properly connected to safety earth
ground. A grounding wire (#18 AWG or larger)
must be attached securely to the test fixture at a
screw terminal designed for safety grounding. The
other end of the ground wire must be attached to a
known safety earth ground.
Construction Material: A metal test fixture must be connected to a
known safety earth ground as described in the WARNING above.
WARNING
A nonmetallic test fixture must be constructed
of materials that are suitable for flammability,
voltage, and temperature conditions that may exist
in the test circuit. The construction requirements
for a nonmetallic enclosure are also described in
the WARNING above.
Test Circuit Isolation: With the lid closed, the test fixture must
completely surround the test circuit. A metal test fixture must be
electrically isolated from the test circuit. Input/output connectors
mounted on a metal test fixture must also be isolated from the test
fixture. Internally, Teflon® standoffs are typically used to insulate
the internal pc-board or guard plate for the test circuit from a
metal test fixture.
Interlock Switch: The test fixture must have a normally open interlock switch. The interlock switch must be installed so that, when
the lid of the test fixture is opened, the switch will open, and
when the lid is closed, the switch will close.
WARNING
When an interlock is required for safety, a separate
circuit should be provided that meets the requirements of the application to protect the operator reliably from exposed voltages. The output enable pin
1-1
Section 1
General Information
on the digital I/O port on the Models 2601 and 2602
System SourceMeter instruments is not suitable for
control of safety circuits and should not be used to
control a safety interlock. The Interlock pin on the
digital I/O port for the Models 2611, 2612, 2635, and
2636 can be used to control a safety interlock.
Computer: The test programs in this document require a PC with
IEEE-488 (GPIB) communications and cabling.
Software: Series 2600 System SourceMeter instruments each
use a powerful on-board test sequencer known as the Test Script
Processor (TSP™). The TSP is accessed through the instrument
communications port, most often, the GPIB. The test program, or
script, is simply a text file that contains commands that instruct
the instrument to perform certain actions. Scripts can be written
in many different styles as well as utilizing different programming
environments. This guide discusses script creation and management using Keithley Test Script Builder (TSB), an easy-to-use program that allows you to create, edit, and manage test scripts. For
more information on TSB and scripting, see Section 2: Using Test
Script Builder of the Series 2600 Reference Manual.
Connections and Cabling: High quality cabling, such as the
Keithley Model 2600-BAN or Model 7078-TRX-3 triaxial cables,
should be used whenever possible.
1.2.2 Remote/Local Sensing
Considerations
In order to simplify the test connections, most applications in
this guide use local sensing for the SMUs. Local sensing requires
connecting only two cables between the SMUs and the test fixture
(OUTPUT HI and OUTPUT LO).
When sourcing and/or measuring voltage in a low impedance
test circuit, there can be errors associated with IR drops in the
test leads. Using four-wire remote sense connections optimizes
voltage source and measure accuracy. When sourcing voltage,
four-wire remote sensing ensures that the programmed voltage is
delivered to the DUT. When measuring voltage, only the voltage
drop across the DUT is measured. Use four-wire remote sensing
for the following source-measure conditions:
• Sourcing and/or measuring voltage in low impedance (<1kW)
test circuits.
• Enforcing voltage compliance limit directly at the DUT.
1.3 Graphing
All of the programs in this guide print the data to the TSB Instrument Console. In some cases, graphing the data can help you visualize the characteristics of the DUT. One method of graphing is to
copy and paste the data from the TSB Instrument Console and
place it in a spreadsheet program such as Microsoft Excel.
After the script has run, and the data has been returned to the
Instrument Console, you can highlight it by using the PC’s mouse:
depress the Control and c (commonly written as Ctrl+c) keys on
the keyboard simultaneously, switch to an open Excel worksheet,
and depress Control and v simultaneously (Ctrl+v). The data
should now be placed in the open worksheet columns so you can
use the normal graphing tools available in your spreadsheet program to graph the data as needed.
This Applications Guide is designed for Series 2600 instrument users who want to create their own scripts using the Test Script
Builder software. Other options include LabTracer® 2 software, the Automated Characterization Suite (ACS), and a LabVIEW driver.
1-2
Section 2
Two-terminal Device Tests
2.1 Introduction
2.3.1 Test Configuration
Two-terminal device tests discussed in this section include voltage
coefficient tests on resistors, leakage tests on capacitors, and diode
characterization.
The test configuration for voltage coefficient measurements is
shown in Figure 2-2. One SMU sources the voltage across the
resistor under test and measures the resulting current through
the resistor.
2.2 Instrument Connections
Figure 2-1 shows the instrument connections for two-terminal
device tests. Note that only one channel of a Source-Measure Unit
(SMU) is required for these applications. Be aware that multichannel models, such as the Model 2602, can be used, but are not
required to run the test program.
2.3.2 Voltage Coefficient Calculations
Two different current readings at two different voltage values are
required to calculate the voltage coefficient. Two resistance read-
Series 2600 Rear Panel
WARNING
Lethal voltages may be present. To avoid a possible
shock hazard, the test system should be equipped
with protective shielding and a safety interlock
circuit. For more information on interlock techniques, see Section 10 of the Series 2600 Reference
manual.
HI
Turn off all power before connecting or disconnecting wires or cables.
NOTES
1. Remote sensing connections are recommended for optimum
accuracy. See paragraph 1.2.2 for details.
DUT
LO
Figure 2-1. Series 2600 two-wire connections (local
sensing)
2. If measurement noise is a problem, or for critical, low level
applications, use shielded cable for all signal connections.
2.3 Voltage Coefficient
Tests of Resistors
Resistors often show a change in resistance with applied voltage
with high megohm resistors (>109W) showing the most pronounced effects. This change in resistance can be characterized as
the voltage coefficient. The following paragraphs discuss voltage
coefficient tests using a single-channel Model 2601 System SourceMeter instrument. The testing can be performed using any of the
Series 2600 System SourceMeter instruments.
Output HI
Series 2600
System
SourceMeter
Channel A
Source V,
Measure I
R = V/I
I
V
Test
Fixture
R
Resistor
Under
Test
Output LO
Figure 2-2. Voltage coefficient test configuration
2-1
Section 2
Two-terminal Device Tests
ings, R1 and R 2, are then obtained, and the voltage coefficient in
%/V can then be calculated as follows:
can be used with the multi-channel members of the Series 2600
family with no modification.
100 (R2 – R1)
Voltage Coefficient (%/V) = __________
R1 (V2 – V1)
1. With the power off, connect the Model 2601 System SourceMeter instrument to the computer’s IEEE-488 interface.
where:R1 =resistance calculated with first applied voltage (V1).
2. Connect the test fixture to the instrument using appropriate
­cables (see Figure 2-1).
R 2 =resistance calculated with second applied voltage
(V2).
For example, assume that the following values are obtained:
R1 = 1.01 × 1010W
R 2 = 1 × 1010W
(V2 – V1) = 10V
The voltage coefficient is:
100 (1×103)
Voltage Coefficient (%/V) = __________
= 0.1%/V
1×1010 (10)
2.3.3 Measurement Considerations
A couple of points should be noted when using this procedure to
determine the voltage coefficient of high megohm resistors. Keep
in mind that any leakage resistance in the test system will degrade
the accuracy of your measurements. To avoid such problems, use
only high quality test fixtures that have insulation resistances
greater than the resistances being measured. Using isolation resistances 10× greater than the measured resistance is a good rule of
thumb. Also, make certain that the test fixture sockets are kept
clean and free of contamination as oils and dirt can lower the
resistance of the fixture and cause error in the measurement.
There is an upper limit on the resistance value that can be
measured using this test configuration. For one thing, even a
well-­designed test fixture has a finite (although very high) path
isolation value. Secondly, the maximum resistance is determined
by the test voltage and current-measurement resolution of the test
instrument. Finally, the instrument has a typical output impedance of 1015W. To maximize measurement accuracy with a given
resistor, use the highest test voltages possible.
2.3.4Example Program 1: Voltage
Coefficient Test
Program 1 demonstrates programming techniques for voltage
coefficient tests. Follow the steps that follow to use the test program. To reiterate, this test requires a single Source-Measure
channel. For this example, we will refer to the single-channel
Model 2601 System SourceMeter instrument. The test program
2-2
3. Turn on the instrument, and allow the unit to warm up for
two hours for rated accuracy.
4. Turn on the computer and start Test Script Builder (TSB). Once
the program has started, open a session by connecting to the
instrument. For details on how to use TSB, see the Series 2600
Reference Manual.
5. You can simply copy and paste the code from Appendix A
in this guide into the TSB script editing window (Program
1: Voltage Coefficient), manually enter the code from the
appendix, or import the TSP file ‘Volt_Co.tsp’ after downloading it to your PC.
If your computer is currently connected to the Internet, you
can click on this link to begin downloading: http://www.
keithley.com/data?asset=50914.
6. Install the resistor being tested in the test fixture. The first
step in the operation requires us first to send the code to the
instrument. The simplest method is to right-click in the open
script window of TSB, and select ‘Run as TSP file’. This will
compile the code and place it in the volatile run-time memory
of the instrument. To store the program in non-volatile
memory, see the “TSP Programming Fundamentals” section of
the Series 2600 Reference Manual.
7. Once the code has been placed in the instrument run-time
memory, we can run it simply by calling the function ‘Volt _
Co()’. This can be done by typing the text ‘Volt _ Co()’ ­after
the active prompt in the Instrument Console line of TSB.
8. In the program ‘Volt_Co.tsp’, the function Volt _
Co(v1src, v2src) is created. The variables v1src and
v2src represent the two test voltage values applied to the
device-under-test (DUT). If they are left blank, the function
will use the default values given to these variables, but you can
specify what voltages are applied by simply sending voltages
that are in-range in the function call. As an example, if you
wanted to source 2V followed by 10V, simply send Volt _
Co(2, 10) to the instrument.
9. The instrument will then source the programmed voltages
and measure the respective currents through the resistor. The
calculated voltage coefficient and two resistance values will
then be displayed in the Instrument Console window of TSB.
Section 2
Two-terminal Device Tests
2.3.5 Typical Program 1 Results
Note: If the compliance is true, the instrument will abort the program and print a warning to the TSB window. Check the DUT
and cabling to make sure everything is connected correctly and
re-run the test.
The actual voltage coefficient you obtain using the program will,
of course, depend on the resistor being tested. The typical voltage
coefficient obtained for a 10GW resistor (Keithley part number
R-319-10G) was about 8ppm/V (0.008%/V).
2.4 Capacitor Leakage Test
2.3.6 Program 1 Description
One important parameter associated with capacitors is leakage
current. Once the leakage current is known, the insulation resistance can be easily calculated. The amount of leakage current in
a capacitor depends both on the type of dielectric as well as the
applied voltage. With a test voltage of 100V, for example, ceramic
dielectric capacitors have typical leakage currents in the nanoamp
to picoamp range, while polystyrene and polyester dielectric
capacitors exhibit a much lower leakage current—typically in the
femtoamp (10 –15A) range
At the start of the program, the instrument is reset to default conditions, and the error queue and data storage buffers are cleared.
The following configuration is then applied before the data collection begins:
• Source V, DC mode
• Local sense
• 100mA compliance, autorange measure
2.4.1 Test Configuration
• 1NPLC line cycle integration
• v1src: 100V
Figure 2-3 shows the test configuration for the capacitor leakage
test. The instrument sources the test voltage across the capacitor,
and it measures the resulting leakage current through the device.
The resistor, R, is included for current limiting, and it also helps
to reduce noise. A typical value for R is 1MW, although that value
can be decreased for larger capacitor values. Note, however, that
values less than 10kW are not recommended.
• v2src: 200V
The instrument then sources v1src, checks the source for compliance in the function named Check _ Comp(), and performs a
measurement of the current if compliance is false. The source then
applies v2src and performs a second current measurement.
2.4.2 Leakage Resistance Calculations
The function Calc _ Val() then performs the calculation of the
voltage coefficient based on the programmed source values and
the measured current values as described in Section 2.3.2, Voltage
Coefficient Calculations.
Once the leakage current is known, the leakage resistance can
easily be calculated from the applied voltage and leakage current
value as follows:
The instrument output is then turned off and the function
Print _ Data() is run to print the data to the TSB window.
Output HI
Series 2600
System
SourceMeter
Channel A
Source V,
Measure I
R = V/I
I LKG
I
V
Output LO
Test
Fixture
C
R
Capacitor
Under
Test
Resistor R required to
limit current and
reduce noise.
Typical value: 1MΩ
Minimum value: 10kΩ
Figure 2-3. Test configuration for capacitor leakage test
2-3
Section 2
Two-terminal Device Tests
For example, assume that you measured a leakage current of 25nA
with a test voltage of 100V. The leakage resistance is simply:
R =100/25nA = 4GW (4 × 109W)
2.4.3 Measurement Considerations
After the voltage is applied to the capacitor, the device must be
allowed to charge fully before the current measurement can be
made. Otherwise, an erroneous current, with a much higher
value, will be measured. The time period during which the capacitor charges is often termed the “soak” time. A typical soak time is
seven time constants, or 7RC, which would allow settling to less
than 0.1% of final value. For example, if R is 1MW, and C is 1µF,
the recommended soak time is seven seconds. With small leakage
currents (<1nA), it may be necessary to use a fixed measurement
range instead of auto ranging.
2.4.4Example Program 2:
Capacitor Leakage Test
Program 2 performs the capacitor leakage test described above.
Follow the steps that follow to run the test using this program.
WARNING
Hazardous voltage may be present on the capacitor
leads after running this test. Discharge the capacitor before removing it from the test fixture.
1. With the power off, connect the instrument to the computer’s
IEEE-488 interface.
2. Connect the test fixture to the instrument using appropriate
cables.
3. Turn on the instrument, and allow the unit to warm up for
two hours for rated accuracy.
4. Turn on the computer and start Test Script Builder (TSB). Once
the program has started, open a session by connecting to the
instrument. For details on how to use TSB, see the Series 2600
Reference Manual.
5. You can simply copy and paste the code from Appendix A in
this guide into the TSB script editing window (Program 2),
manually enter the code from the appendix, or import the TSP
file ‘Cap_Leak.tsp’ after downloading it to your PC.
If your computer is currently connected to the Internet, you
can click on this link to begin downloading: http://www.
keithley.com/data?asset=50927.
6. Discharge and install the capacitor being tested, along with
the series resistor, in the appropriate axial component sockets
of the test fixture.
2-4
WARNING
Care should be taken when discharging the capacitor, as the voltage present may represent a shock
hazard!
7. Now, we must send the code to the instrument. The simplest
method is to right-click in the open script window of TSB,
and select ‘Run as TSP file’. This will compile the code and
place it in the volatile run-time memory of the instrument.
To store the program in non-volatile memory, see the “TSP
Programming Fundamentals” section of the Series 2600 Reference Manual.
8. Once the code has been placed in the instrument run-time
memory, we can run it at any time simply by calling the function ‘Cap _ Leak()’. This can be done by typing the text
‘Cap _ Leak()’ after the active prompt in the Instrument
Console line of TSB.
9. In the program ‘Cap_Leak.tsp’, the function Cap _
Leak(vsrc) is created. The variable vsrc represents the
test voltage value applied to the device-under-test (DUT). If
it is left blank, the function will use the default value given
to the variable, but you can specify what voltage is applied
by simply sending a voltage that is in-range in the function
call. As an example, if you wanted to source 100V, simply send
Cap _ Leak(100) to the instrument.
10.The instrument will then source the programmed voltage and
measure the respective current through the capacitor. The
measured current leakage and calculated resistance value will
then be displayed in the Instrument Console window of TSB.
NOTE
The capacitor should be fully discharged before running the test. This can be accomplished by sourcing 0V
on the device for the soak time or by shorting the leads
together. Care should be taken because some capacitors
can hold a charge for a significant period of time and
could pose an electrocution risk.
The soak time, denoted in the code as the variable l _ soak,
has a default value of 10s. When entering the soak time, choose
a value of at least 7RC to allow settling to within 0.1% of final
value. At very low currents (<500fA), a longer settling time may
be required to compensate for dielectric absorption, especially at
high ­voltages.
2.4.5 Typical Program 2 Results
As pointed out earlier, the exact value of leakage current will
depend on the capacitor value as well as the dielectric. A typical
value obtained for 1µF aluminum electrolytic capacitor was about
80nA at 25V.
Section 2
Two-terminal Device Tests
2.4.6 Program 2 Description
Staircase Sweep
• Source V, DC mode
• Local sense
• 10mA compliance, autorange measure
Sourced Value
At the start of the program, the instrument is reset to default conditions, the error queue, and data storage buffers are cleared. The
following configuration is then applied before the data collection
begins:
• 1 NPLC Line cycle integration
• vsrc: 40V
The instrument then sources vsrc, checks the source for compliance in the function named Check _ Comp(), and performs a
measurement of the current if compliance is false.
The function Calc _ Val() then performs the calculation of
the leakage resistance based on the programmed source value
and the measured current value as described in paragraph 2.4.2,
Leakage Resistance Calculations.
The instrument output is then turned off and the function
Print _ Data() is run to print the data to the TSB window.
Note: If the compliance is true, the instrument will abort the program and print a warning to the TSB window. Check the DUT
and cabling to make sure everything is connected correctly and
re-run the test.
2.5 Diode Characterization
The System SourceMeter instrument is ideal for characterizing
diodes because it can source a current through the device, and
measure the resulting forward voltage drop (V F) across the ­device.
A standard technique for diode characterization is to perform a
staircase sweep (Figure 2-4) of the source current from a starting
value to an end value while measuring the voltage at each current
step. The following paragraphs discuss the test configuration and
give a sample test program for such tests.
2.5.1 Test Configuration
Figure 2-5 shows the test configuration for the diode characterization test. The System SourceMeter instrument is used to source
the forward current (IF) through the diode under test, and it also
measures the forward voltage (V F) across the device. IF is swept
across the desired range of values, and V F is measured at each current. Note that the same general configuration could be used to
Time
Figure 2-4. Staircase sweep
Output HI
Series 2600
System
SourceMeter
Channel A
Sweep IF,
Measure VF
I
V
IF
Diode
Under
Test
VF
Test
Fixture
Output LO
Figure 2-5. Test configuration for diode characterization
measure leakage current by reversing the diode, sourcing voltage,
and measuring the leakage current.
2.5.2 Measurement Considerations
Because the voltages being measured will be fairly small (≈0.6V),
remote sensing can be used to minimize the effects of voltage
drops across the test connections and in the test fixture. Remote
sensing requires the use of the Sense connections on the System
SourceMeter channel being used, as well as changing the code to
reflect remote sensing. For more information on remote sensing,
see the Series 2600 Reference Manual.
2.5.3Example Program 3:
Diode Characterization
Program 3 demonstrates the basic programming techniques for
running the diode characterization test. Follow these steps to use
this program:
2-5
Section 2
Two-terminal Device Tests
1. With the power off, connect the instrument to the computer’s
IEEE-488 interface.
Diode Forward Characteristics
9.00E–01
2. Connect the test fixture to the instrument using appropriate
cables.
4. Turn on the computer and start Test Script Builder (TSB). Once
the program has started, open a session by connecting to the
instrument. For details on how to use TSB, see the ­Series 2600
Reference Manual.
5. You can simply copy and paste the code from Appendix A in
this guide into the TSB script editing window (Program 3A,
Diode Forward Characterization), manually enter the code
from the appendix, or import the TSP file ‘Diode_Fwd_Char.
tsp’ after downloading it to your PC.
If your computer is currently connected to the Internet, you
can click on this link to begin downloading: http://www.
keithley.com/data?asset=50924.
6. Install a small-signal silicon diode such as a 1N914 or 1N4148
in the appropriate axial socket of the test fixture.
7. Now, we must send the code to the instrument. One method
is simply to right-click in the open script window of TSB, and
select ‘Run as TSP file’. This will compile the code and place
it in the volatile run-time memory of the instrument. To store
the program in non-volatile memory, see the “TSP Programming Fundamentals” section of the Series 2600 Reference
Manual.
8. Once the code has been placed in the instrument run-time
memory, we can run it at any time simply by calling the function ‘Diode_Fwd_Char()’. This can be done by typing the text
‘Diode _ Fwd _ Char()’ after the active prompt in the
Instrument Console line of TSB.
9. In the program ‘Diode_Fwd_Char.tsp’, the function ­Diode _
Fwd _ Char(ilevel, start, stop, steps) is
created. The variable ilevel represents the current value
applied to the device-under-test (DUT) both before and after
the staircase sweep has been applied. The start variable
represents the starting current value for the sweep, stop represents the end current value, and steps represents the number
of steps in the sweep. If any values are left blank, the function
will use the default value given to that variable, but you can
specify what voltage is applied by simply sending a voltage that
is in-range in the function call.
10.As an example, if you wanted to configure a test that would
source 0mA before and after the sweep, with a sweep start
value of 1mA, stop value of 10mA, and 10 steps, you would
2-6
7.00E–01
Voltage (Volts)
3. Turn on the instrument, and allow the unit to warm up for
two hours for rated accuracy.
Voltage Data (V)
8.00E–01
6.00E–01
5.00E–01
4.00E–01
3.00E–01
2.00E–01
1.00E–01
0.00E–00
0.00E+00
2.00E–03
4.00E–03
6.00E–03
8.00E–03
1.00E–02
Current (Amps)
Figure 2-6. Program 3 results: Diode forward
characteristics
simply send Diode _ Fwd _ Char(0, 0.001, 0.01,
10) to the instrument.
11.The instrument will then source the programmed current
staircase sweep and measure the respective voltage at each
step. The measured and sourced values are then printed to
the screen (if using TSB). To graph the results, simply copy
and paste the data into a spreadsheet such as Microsoft Excel
and chart.
2.5.4 Typical Program 3 Results
Figure 2-6 shows typical results obtained using Example Program
3. These results are for a 1N914 silicon diode.
2.5.5 Program 3 Description
At the start of the program, the instrument is reset to default conditions, the error queue, and data storage buffers are cleared. The
following configuration is then applied before the data collection
begins:
• Source I
• Local sense
• 10V compliance, autorange measure
• Ilevel: 0A
• start: 0.001A
• stop: 0.01A
• steps: 10
The instrument then sources ilevel, dwells l _ delay seconds, and begins the staircase sweep from start to stop in
steps. At each current step, both the current and voltage are
measured.
Section 2
Two-terminal Device Tests
The instrument output is then turned off and the function
Print _ Data() is run to print the data to the TSB window. To
graph the results, simply copy and paste the data into a spreadsheet such as Microsoft Excel and chart.
and place it in the volatile run-time memory of the instrument.
To store the program in non-volatile memory, see the “TSP Programming Fundamentals” section of the Series 2600 Reference
Manual.
2.5.6 Using Log Sweeps
Once the code has been placed in the instrument run-time
memory, we can run it at any time simply by calling the function
‘Diode_Fwd_Char_Log()’. This can be done by typing the text
‘Diode _ Fwd _ Char _ Log()’ after the active prompt in the
Instrument Console line of TSB.
With some devices, it may be desirable to use a log sweep because
of the wide range of currents necessary to perform the test. Program 3B performs a log sweep of the diode current.
If your computer is currently connected to the Internet, you can
click on this link to begin downloading ‘Diode_Fwd_Char_Log.
tsp’: http://www.keithley.com/data?asset=50923.
2.5.7 Using Pulsed Sweeps
Note that the start and stop currents are programmed just as
before, although with a much wider range than would be practical
with a linear sweep. With log sweep, however, the points param­
eter, which defines the number of points per decade, replaces the
steps parameter that is used with the linear sweep.
In some cases, it may be desirable to use a pulsed sweep to avoid
device self-heating that could affect the test results. Program 3C
performs a staircase pulse sweep. In this program, there are two
additional variables ton and toff, where ton is the source on duration and toff is the source off time for the pulse. During the toff
portions of the sweep, the source value is returned to the ilevel
bias value.
To run the Log sweep, we must send the code to the instrument.
One method is simply to right-click in the open script window
of TSB, and select ‘Run as TSP file’. This will compile the code
If your computer is currently connected to the Internet, you can
click on this link to begin downloading ‘Diode_Fwd_Char_Pulse.
tsp’: http://www.keithley.com/data?asset=50922.
2-7
Section 2
Two-terminal Device Tests
2-8
Section 3
Bipolar Transistor Tests
3.1 Introduction
interlock of the Series 2600, please see the Series
2600 Reference Manual.
Bipolar transistor tests discussed in this section include: tests to
generate common-emitter characteristic curves, Gummel plot,
current gain, and transistor leakage tests.
NOTES
Remote sensing connections are recommended for
optimum accuracy. See paragraph 1.2.2 for details.
3.2 Instrument Connections
If measurement noise is a problem, or for critical, low
level applications, use shielded cable for all signal
connections.
Figure 3-1 shows the instrument connections for the bipolar
transistor tests outlined in this section. Two Source-Measure
channels are required for the tests (except for the leakage current
test, which requires only one Source-Measure channel).
Keithley Model 2600-BAN cables or Model 7078-TRX-3 low noise
triaxial cables are recommended to make instrument-to-test fixture connections. In addition, the safety interlock connecting
cables must be connected to the instrument and fixture if using
instrumentation capable of producing greater than 42V.
WARNING
Lethal voltages may be exposed when working with
test fixtures. To avoid a possible shock hazard, the
fixture must be equipped with a working safety
interlock circuit. For more information on the
3.3 Common-Emitter
Characteristics
Common-emitter characteristics are probably the most familiar
type of curves generated for bipolar transistors. Test data used to
generate these curves is obtained by sweeping the base current
(IB) across the desired range of values at specific increments. At
each be current value, the collector-emitter voltage (VCE) is swept
across the desired range, again at specific increments. At each VCE
value, the collector current (IC) is measured.
Once the data is collected, it is conveniently printed (if using TSB).
You can then use the copy-and-paste method to place the data
into a spreadsheet program such as Microsoft Excel. Common
Transistor
Under Test
IB
Output HI
Series 2600
System
SourceMeter
Channel B
Sweep IB
I
V
IC
Output HI
VCE
Test
Fixture
I
V
Series 2600
System
SourceMeter
Channel A
Sweep VCE ,
Measure IC
Output LO
Output LO
Figure 3-1. Test configuration for common-emitter tests
3-1
Section 3
Bipolar Transistor Tests
plotting styles include graphing IC vs. VCE for each value of IB. The
result is a family of curves that shows how IC varies with VCE at
specific IB values.
3.3.1 Test Configuration
Figure 3-1 shows the test configuration for the common-emitter
characteristic tests. Many of the transistor tests performed require
two Source-Measure Units (SMUs). The Series 2600 System
SourceMeter instruments have dual-channel members such as the
Model 2602, 2612, and 2636. This offers a convenient transistor
test system all in one box. The tests can be run using two singlechannel instruments, but the code will have to be modified to
do so.
In this test, SMUB sweeps IB across the desired range, and SMUA
sweeps VCE and measures IC. Note that an NPN transistor is shown
as part of the test configuration. A small-signal NPN transistor
with an approximate current gain of 500 (such as a 2N5089) is
recommended for use with the test program below. Other similar
transistors such as a 2N3904 may also be used, but the program
may require modification.
3.3.2 Measurement Considerations
A fixed delay period of 100ms, which is included in the program,
may not be sufficient for testing some devices. Also, it maybe necessary to change the programmed current values to optimize the
tests for a particular device.
3.3.3Example Program 4:
Common-Emitter Characteristics
Program 4 can be used to run common-emitter characteristic tests
on small-signal NPN transistors. In order to run the program,
follow these steps:
1. With the power off, connect a dual-channel System SourceMeter instrument to the computer’s IEEE-488 interface.
2. Connect the test fixture to both units using appropriate cables
(see Figure 3-1).
3. Turn on the instrument and allow the unit to warm up for two
hours for rated accuracy.
4. Turn on the computer and start Test Script Builder (TSB). Once
the program has started, open a session by connecting to the
instrument. For details on how to use TSB, see the ­Series 2600
Reference Manual.
5. You can simply copy and paste the code from Appendix A in
this guide into the TSB script editing window (Program 4),
manually enter the code from the appendix, or import the TSP
file ‘BJT_Comm_Emit.tsp’ after downloading it to your PC.
3-2
If your computer is currently connected to the Internet, you
can click on this link to begin downloading: http://www.
keithley.com/data?asset=50930.
6. Install an NPN transistor such as a 2N5089 in the appropriate
transistor socket of the test fixture.
7. Now, we must send the code to the instrument. The simplest
method is to right-click in the open script window of TSB,
and select ‘Run as TSP file’. This will compile the code and
place it in the volatile run-time memory of the instrument.
To store the program in non-volatile memory, see the “TSP
Programming Fundamentals” section of the Series 2600 Reference Manual.
8. Once the code has been placed in the instrument run-time
memory, we can run it at any time simply by calling the function ‘BJT _ Comm _ Emit()’. This can be done by typing
the text ‘BJT _ Comm _ Emit()’ after the active prompt in
the Instrument Console line of TSB.
9. In the program ‘BJT_Comm_Emit.tsp’, the function BJT _
Comm _ Emit(istart, istop, isteps, vstart,
vstop, vsteps) is created.
• istart represents the sweep start current value on the
base of the transistor
• istop represents the sweep stop value
• isteps is the number of steps in the base current sweep
• vstart represents the sweep start voltage value on the
collector-emitter of the transistor
• vstop represents the sweep stop voltage value
• vsteps is the number of steps in the base current sweep
If these values are left blank, the function will use the default
values given to the variables, but you can specify each variable
value by simply sending a number that is in-range in the function call. As an example, if you wanted to have the base current
swept from 1µA to 100µA in 10 steps, and the collector-emitter
voltage (VCEO) to be swept from 0 to 10V in 1V steps, you would
send BJT _ Comm _ Emit(1E-6, 100E-6, 10, 0, 10,
10) to the instrument.
10.The instrument will then source the programmed start current
on the base, sweep the voltage on the collector-emitter, and
measure the respective current through the collector-emitter.
The base current will be incremented and the collector-emitter
sweep will take place again. After the final base source value
and associated collector-emitter sweep, the collector-emitter
voltage (VCE), measured collector-emitter current (ICE), and
base current (IB) values will then be displayed in the Instrument Console window of TSB.
Section 3
Bipolar Transistor Tests
Common-Emitter Characteristics (2N5089)
5.00E–02
I C (Amps)
4.00E–02
3.00E–02
I B = 50µA
I B = 40µA
2.00E–02
I B = 30µA
I B = 20µA
1.00E–02
I B = 10µA
0.00E+00
0
1
2
3
4
5
6
7
8
9
10
VBE (Volts)
Figure 3-2. Program 4 results: Common-emitter characteristics
3.3.4 Typical Program 4 Results
Figure 3-2 shows typical results generated by Example Program 4.
A 2N5089 NPN transistor was used to generate these test results.
3.3.5 Program 4 Description
For the following program description, refer to the program
listing below.
• Source I
• IV compliance, 1.1V range
for SMUA are measured. The source value for SMUA is then
incremented by l _ vstep, and the sweep is continued until
the source value reaches vstop. Then, SMUB is incremented by
l _ istep and SMUA begins another sweep from vstart to
vstop in vsteps. This nested sweeping process continues until
SMUB reaches istop.
The instrument output is then turned off and the function
Print _ Data() is run to print the data to the TSB window. To
graph the results, simply copy and paste the data into a spreadsheet such as Microsoft Excel and chart.
• Local sense
• istart current: 10M
• istop current: 50µA
• isteps: 5
Following SMUB setup, SMUA, which sweeps VCE and measures
IC, is programmed as follows:
• Source V
• Local sensing
• 100mA compliance, autorange measure
• 1 NPLC Line cycle integration (to reduce noise)
• vstart: 0V
• vstop: 10V
3.4 Gummel Plot
A Gummel plot is often used to determine current gain variations
of a transistor. Data for a Gummel plot is obtained by sweeping
the base-emitter voltage (V BE) across the desired range of values at
specific increments. At each V BE value, both the base current (IB)
and collector current (IC) are measured.
Once the data are taken, the data for IB, IC, and V BE is returned to
the screen. If using TSB, a plot can be generated using the “copyand-paste” method in a spreadsheet program such as Microsoft
Excel. Because of the large differences in magnitude between IB
and IC, the Y axis is usually plotted logarithmically.
• vsteps: 100
3.4.1 Test Configuration
Once the two units are configured, the SMUB sources istart,
SMUA sources vstart, and the voltage (VCE) and current (ICE)
Figure 3-3 shows the test configuration for Gummel plot tests.
SMUB is used to sweep V BE across the desired range, and it also
3-3
Section 3
Bipolar Transistor Tests
Transistor
Under Test
Output HI
IB
VCE
Output HI
Series 2600
System
SourceMeter
Channel B
Sweep VBE
Measure IB
IC
VBE
I
V
Test
Fixture
I
V
Series 2600
System
SourceMeter
Channel A
Source VCE ,
Measure IC
Output LO
Output LO
Figure 3-3. Gummel plot test configuration
measures IB. SMUA sets VCE to the desired fixed value, and it also
measures IC.
Due to the low current measurements associated with this type of
testing, the Keithley Model 2636 System SourceMeter instrument
is recommended. Its low level current measurement capabilities
and dual-channel configuration are ideal for producing high
quality Gummel plots of transistors.
3.4.2 Measurement Considerations
As written, the range of V BE test values is from 0V to 0.7V in 0.01V
increments. It may be necessary, however, to change these limits
for best results with your particular device. Low currents will be
measured so take the usual low current precautions.
3.4.3Example Program 5: Gummel Plot
Program 5 demonstrates the basic programming techniques
for generating a Gummel plot. Follow these steps to run this
program:
1. With the power off, connect a dual-channel System SourceMeter instrument to the computer’s IEEE-488 interface.
2. Connect the test fixture to both units using appropriate
­cables.
3. Turn on the instrument and allow the unit to warm up for two
hours for rated accuracy.
4. Turn on the computer and start Test Script Builder (TSB). Once
the program has started, open a session by connecting to the
instrument. For details on how to use TSB, see the ­Series 2600
Reference Manual.
3-4
5. You can simply copy and paste the code from Appendix A in
this guide into the TSB script editing window (Program 5),
manually enter the code from the appendix, or import the TSP
file ‘Gummel.tsp’ after downloading it to your PC.
If your computer is currently connected to the Internet, you
can click on this link to begin downloading: http://www.
keithley.com/data?asset=50918
6. Install an NPN transistor such as a 2N5089 in the appropriate
transistor socket of the test fixture.
7. Now, we must send the code to the instrument. The simplest
method is to right-click in the open script window of TSB,
and select ‘Run as TSP file’. This will compile the code and
place it in the volatile run-time memory of the instrument.
To store the program in non-volatile memory, see the “TSP
Programming Fundamentals” section of the Series 2600 Reference Manual.
8. Once the code has been placed in the instrument run-time
memory, we can run it at any time simply by calling the
function ‘Gummel()’. This can be done by typing the text
­‘Gummel()’ after the active prompt in the Instrument Console line of TSB.
9. In the program ‘Gummel.tsp’, the function ­Gummel
(vbestart, vbestop, vbesteps, vcebias) is
­
­created.
• vbestart represents the sweep start voltage value on
the base of the transistor
• vbestop represents the sweep stop value
• vbesteps is the number of steps in the base
voltage sweep
Section 3
Bipolar Transistor Tests
• vcebias represents the voltage bias value on the
collector-emitter of the transistor
• vbestart: 0V
If these values are left blank, the function will use the default
values given to the variables, but you can specify each variable
value by simply sending a number that is in-range in the function call. As an example, if you wanted to have the base voltage
swept from 0.1V to 1V in 10 steps, and the collector-emitter
voltage (VCE) to be biased 5V, you would send Gummel(0.1,
1, 10, 5) to the instrument.
10.The base-emitter voltage will be swept between 0V and 0.7V in
0.01V increments, and both IB and IC will be measured at each
V BE value. Note that a fixed collector-emitter voltage of 10V is
used for the tests.
11.Once the sweep has been completed, the data (IB, IC, and V BE)
will be presented in the Instrument Console window of TSB.
• vbestop: 0.7V
• vbesteps: 70
SMUA, which sources VCE and measures IC, is programmed in the
following manner:
• Source V
• Local sensing
• 100mA compliance, autorange measure
• 1 NPLC Line cycle integration
• Constant sweep (number of points programmed to 71),
VCE = 10V
• vcebias: 10V
3.4.4 Typical Program 5 Results
Figure 3-4 displays a typical Gummel plot as generated by
­Example Program 5. Again, the transistor used for this example
was a 2N5089 NPN silicon transistor.
Following unit setup, both unit triggers are armed, and the instruments are placed into the operate mode (lines 320 and 330).
Once triggered, SMUB sets V BE to the required value, and SMUA
then sets VCE and measures IC at IB. At the end of its measurement,
SMUB increments V BE and the cycle repeats until V BE reaches the
value set for vbestop.
3.4.5 Program 5 Description
SMUB, which sweeps V BE and measures IB, is set up as follows:
• Source V
During the test, V BE, IB, and IC are measured. Once the test has
completed, the data is written to the Instrument Console of TSB
and can be graphed in a spreadsheet program using the “copyand-paste” method of data transfer.
• 1mA compliance, autorange measure
• Local sensing
• 1 NPLC Line cycle integration
Gummel Plot (2N5089)
1.00E+00
VBE vs. I B
Current (Amps)
1.00E–02
1.00E–04
VBE vs. I C
1.00E–06
1.00E–08
1.00E–10
1.00E–12
1.00E–14
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
VBE (Volts)
Figure 3-4. Program 5 results: Gummel plot
3-5
Section 3
Bipolar Transistor Tests
3.5 Current Gain
The following paragraphs discuss two methods for determining
DC current gain, as well as ways to measure AC current gain.
Tests for both DC and AC current gain are generally done at one
specific value of VCE. AC current gain tests should be performed
with as small a ∆IB as possible so that the device remains in the
linear region of the curve.
3.5.2 Test Configuration for
Search Method
3.5.1 Gain Calculations
The common-emitter DC current gain of a bipolar transistor is
simply the ratio of the DC collector current to the DC base current
of the device. The DC current gain is calculated as follows:
__
I
ß = C
IB
Figure 3-5 shows the test configuration for the search method of
DC current gain tests and AC gain tests. A dual-channel System
SourceMeter instrument is required for the test. SMUB is used
to supply IB1 and IB2. SMUA sources VCE, and it also measures the
collector currents IC1 and IC2.
where:ß = current gain
3.5.3 Measurement Considerations
IC = DC collector current
IB = DC base current
Often, the differential or AC current gain is used instead of the
DC value because it more closely approximates the performance
of the transistor under small-signal AC conditions. In order to
determine the differential current gain, two values of collector
current (IC1 and IC2) at two different base currents (IB1 and IB2) are
measured. The current gain is then calculated as follows:
When entering the test base currents, take care not to enter values
that will saturate the device. The approximate base current value
can be determined by dividing the desired collector current value
by the typical current gain for the transistor being tested.
3.5.4Example Program 6A: DC Current
Gain Using Search Method
Use Program 6A to perform DC current gain tests on bipolar transistors. Proceed as follows:
∆I
ß = ___C
ac ∆IB
1. With the power off, connect a dual-channel System SourceMeter instrument to the computer’s IEEE-488 interface.
where:ßa = AC current gain
2. Connect the test fixture to both units using appropriate
­cables.
∆IC = IC2 – IC1
∆IB = IB2 – IB1
3. Turn on the System SourceMeter instrument and allow the
unit to warm up for two hours for rated accuracy.
Transistor
Under Test
IB
Output HI
Series 2600
System
SourceMeter
Channel B
Set IB for
desired I C
V
IC
Output HI
VCE
Test
Fixture
I
Output LO
Figure 3-5. Test configuration for current gain tests using search method
3-6
I
V
Series 2600
System
SourceMeter
Channel A
Source VCE ,
Measure IC
Output LO
Section 3
Bipolar Transistor Tests
4. Turn on the computer and start Test Script Builder (TSB). Once
the program has started, open a session by connecting to the
instrument. For details on how to use TSB, see the ­Series 2600
Reference Manual.
5. You can simply copy and paste the code from Appendix A in
this guide into the TSB script editing window (Program 6A),
manually enter the code from the appendix, or import the TSP
file ‘DC_Gain_Search.tsp’ after downloading it to your PC.
If your computer is currently connected to the Internet, you
can click on this link to begin downloading: http://www.
keithley.com/data?asset=50925
6. Install an NPN transistor such as a 2N5089 in the appropriate
transistor socket of the test fixture.
7. Now, we must send the code to the instrument. The simplest
method is to right-click in the open script window of TSB,
and select ‘Run as TSP file’. This will compile the code and
place it in the volatile run-time memory of the instrument.
To store the program in non-volatile memory, see the “TSP
Programming Fundamentals” section of the Series 2600 Reference Manual.
8. Once the code has been placed in the instrument run-time
memory, we can run it at any time simply by calling the function ‘DC_Gain_Search()’. This can be done by typing the text
‘DC _ Gain _ Search()’ after the active prompt in the
Instrument Console line of TSB.
9. In the program ‘DC_Gain_Search.tsp’, the function DC _
Gain _ Search(vcesource,
lowib,
highib,
targetic) is created.
• vcesource represents the voltage value on the
collector-emitter of the transistor
• lowib represents the base current low limit for the
search algorithm
• highib represents the base current high limit for the
search algorithm
• targetic represents the target collector current for the
search algorithm
10.If these values are left blank, the function will use the default
values given to the variables, but you can specify each variable value by simply sending a number that is in-range in
the function call. As an example, if you wanted the collectoremitter voltage (VCE) to be 2.5V, the base current low value
at 10nA, the base current high value at 100nA, and the
target collector current to be 10µA, you would send DC _
Gain _ Search(2.5,10E-9, 100E-9, 10E–6) to the
instrument.
11.The sources will be enabled, and the collector current of
the device will be measured. The program will perform an
iterative search to determine the closest match to the target
IC (within ±5%). The DC current gain of the device at specific
IB and IC values will then be displayed on the computer CRT.
If the search is unsuccessful, the program will print “Iteration Level Reached”. This is an error indicating that the search
reached its limit. Recheck the connections, DUT, and variable
values to make sure they are appropriate for the device.
12.Once the sweep has been completed, the data (IB, IC, and ß)
will be presented in the Instrument Console window of TSB.
3.5.5 Typical Program 6A Results
A typical current gain for a 2N5089 would be about 500. Note,
however, that the current gain of the device could be as low as
300 or as high as 800.
3.5.6 Program 6A Description
Initially, the iteration variables are defined and the instrument is
returned to default conditions. SMUB, which sources IB, is set up
as follows:
• Source I
• IV compliance, 1.1V range
• Local sense
SMUA, which sources VCE and measures IC, is configured as
follows:
• Source V
• Local sense
• 100mA compliance, autorange measure
Once the SMU channels have been configured, the sources values
are programmed to 0 and the outputs are enabled. The base current (IB) is sourced and the program enters into the binary search
algorithm for the target IC by varying the VCE value, measuring the
IC, comparing it to the target IC, and adjusting the VCE value, if necessary. The iteration counter is incremented each cycle through
the algorithm. If the number of iterations has been exceeded, a
message to that effect is displayed, and the program halts.
Assuming that the number of iterations has not been exceeded,
the DC current gain is calculated and displayed in the Instrument
Console window of the TSB.
3.5.7 Modifying Program 6A
For demonstration purposes, the IC target match tolerance is set
to ±5%. You can, of course, change this tolerance as required.
Similarly, the iteration limit is set to 20. Again, this value can be
adjusted for greater or fewer iterations as necessary. Note that it
3-7
Section 3
Bipolar Transistor Tests
may be necessary to increase the number of iterations if the target
range is reduced.
3.5.9Example Program 6B: DC Current
Gain Using Fast Method
3.5.8 Configuration for Fast
Current Gain Tests
Use Program 6B in Appendix A to demonstrate the fast method of
measuring current gain of bipolar transistors. Proceed as follows:
1. With the power off, connect a dual-channel System SourceMeter instrument to the computer’s IEEE-488 interface.
Figure 3-6 shows the test configuration for an alternate method
of current gain tests—one that is much faster than the search
method discussed previously. SMUB is used to supply VCE, and
it also measures IB. SMUA sources the emitter current (IE) rather
than the collector current (IC). Because we are sourcing emitter
current instead of collector current, the current gain calculations
must be modified as follows:
2. Connect the test fixture to both units using appropriate cables.
Note that OUTPUT HI of SMUB is connected to the base of the
DUT, and SENSE HI of SMUB is connected to the emitter.
3. Turn on the System SourceMeter instrument and allow the
unit to warm up for two hours for rated accuracy.
4. Turn on the computer and start Test Script Builder (TSB). Once
the program has started, open a session by connecting to the
instrument. For details on how to use TSB, see the Series 2600
Reference Manual.
_____
I –I
ß = E B
IB
WARNING
When a System SourceMeter instrument is programmed for remote sensing, hazardous voltage
may be present on the SENSE and OUTPUT terminals when the unit is in operation regardless of the
programmed voltage or current. To avoid a possible
shock hazard, always turn off all power before
connecting or disconnecting cables to the SourceMeasure Unit or the associated test fixture.
5. You can simply copy and paste the code from Appendix A in
this guide into the TSB script editing window (Program 6B),
manually enter the code from the appendix, or import the TSP
file ‘DC_Gain_Fast.tsp’ after downloading it to your PC.
If your computer is currently connected to the Internet, you
can click on this link to begin downloading: http://www.
keithley.com/data?asset=50926
6. Install an NPN transistor such as a 2N5089 in the appropriate
transistor socket of the test fixture.
NOTE
Because of the connection convention used, IE and
VCE must be programmed for opposite polarity than
normal. With an NPN transistor, for example, both VCE
and IE must be negative.
Sense LO
Series 2600
System
SourceMeter
Channel B
Source VCE ,
Measure IB
Sense HI
7. Now, we must send the code to the instrument. The simplest
method is to right-click in the open script window of TSB,
and select ‘Run as TSP file’. This will compile the code and
place it in the volatile run-time memory of the instrument.
Output LO
Output LO
V
I
Output HI
IB
Output HI
VCE
IE
Figure 3-6. Test configuration for fast current gain tests
3-8
I
IC
Series 2600
System
SourceMeter
Channel A
Source IE
Test
Fixture
Section 3
Bipolar Transistor Tests
To store the program in non-volatile memory, see the “TSP
Programming Fundamentals” section of the Series 2600 Reference Manual.
8. Once the code has been placed in the instrument run-time
memory, we can run it at any time simply by calling the function ‘DC_Gain_Search_Fast()’. This can be done by typing
the text ‘DC _ Gain _ Search _ Fast()’ after the active
prompt in the Instrument Console line of TSB.
9. In the program ‘DC_Gain_Search_Fast.tsp’, the function
DC _ Gain _ Search _ Fast(vcesource, istart,
istop, isteps) is created.
• vcesource represents the voltage value on the
collector-emitter of the transistor
• istart represents the start value for the base current
sweep
• istop represents the stop value for the base current
sweep
• isteps represents the number of steps in the base
current sweep
If these values are left blank, the function will use the default
values given to the variables, but you can specify each variable value by simply sending a number that is in-range in
the function call. As an example, if you wanted to have the
collector-emitter voltage (VCE) be 2.5V, the base current sweep
start value at 10nA, the base current sweep stop value at
100nA, and the number of steps to be 10, you would send
DC _ Gain _ Search _ Fast(2.5,10E-9,
100E-9,
10) to the instrument.
• 11V compliance, autorange
• istart: –1mA
• istop: –10mA
• isteps: 10
• 10ms delay
• Staircase sweep mode
Both SMU outputs are then zeroed and enabled. Next, SMUB
sources VCE and SMUA begins the current sweep on the emitter
current (IE) from istart to istop in isteps. At each point in the
sweep, SMUB measures the base current (IB). Upon completion of
the sweep, the current gain (ß) is calculated and the data (IB, IC,
and ß ) is printed to the Instrument Console of the TSB.
3.5.11Example Program 7:
AC Current Gain
NOTE
For the sake of simplicity, this program does not include
the iterative search algorithm included in Program 6A.
To test at a specific IC value, first use Program 6A to
determine the base current at that target value, and
enter IB values slightly higher and lower when prompted
to do so in Program 7.
1. With the power off, connect a dual-channel System SourceMeter instrument to the computer’s IEEE-488 interface.
2. Connect the test fixture to both units using appropriate
­
cables.
10.The sources will be enabled, and the collector current of the
device will be measured.
3. Turn on the instrument and allow the unit to warm up for two
hours for rated accuracy.
11.Once the sweep has been completed, the data (IB, IC, and ß)
will be presented in the Instrument Console window of TSB.
Note that the program reverses the polarity of the emitter currents in order to display true polarity.
4. Turn on the computer and start Test Script Builder (TSB). Once
the program has started, open a session by connecting to the
instrument. For details on how to use TSB, see the Series 2600
Reference Manual.
3.5.10Program 6B Description
5. You can simply copy and paste the code from Appendix A in
this guide into the TSB script editing window (Program 7),
manually enter the code from the appendix, or import the TSP
file ‘AC_Gain_.tsp’ after downloading it to your PC.
Initially, both units are returned to default conditions. SMUB,
which sources VCE and measures IB, is set up as follows:
• Source V
• 1mA compliance, autorange measure
• Remote sense
• vcesource: –10V
SMUA, which sources IE, is configured as follows:
• Source I
• Local sense
If your computer is currently connected to the Internet, you
can click on this link to begin downloading: http://www.
keithley.com/data?asset=50931.
6. Install a small-signal NPN silicon transistor such as a 2N5089
in the appropriate transistor socket of the test fixture.
7. Now, we must send the code to the instrument. The simplest
method is to right-click in the open script window of TSB,
and select ‘Run as TSP file’. This will compile the code and
place it in the volatile run-time memory of the instrument.
3-9
Section 3
Bipolar Transistor Tests
To store the program in non-volatile memory, see the “TSP
Programming Fundamentals” section of the Series 2600 Reference Manual.
8. Once the code has been placed in the instrument run-time
memory, we can run it at any time simply by calling the function ‘AC _ Gain()’. This can be done by typing the text
‘AC _ Gain()’ after the active prompt in the Instrument
Console line of TSB.
9. In the program ‘AC_Gain.tsp’, the function AC _ Gain
(vcesource, ib1, ib2) is created.
• vcesource represents the voltage value on the
collector-emitter of the transistor
• ib1 represents the first value for the base current
• ib2 represents the second value for the base current
If these values are left blank, the function will use the default
values given to the variables, but you can specify each variable value by simply sending a number that is in-range in
the function call. As an example, if you wanted to have the
collector-emitter voltage (VCE) be 2.5V, the base current initial
value at 100nA, and the base current second value at 200nA
you would send AC _ Gain(2.5,100E-9, 200E-9) to the
instrument.
Keep the two values as close together as possible so that the
device remains in its linear operating region. A change in IB of
about 20% from one value to another would be a good starting
point.
10.The sources will be zeroed and then enabled. The program
will execute a two-point source and measure process.
11.Once the measurements have completed, the data (IB1, IC1,
IB2, IC2, and ß) will be presented in the Instrument Console
window of TSB.
3.5.13Typical Program 7 Results
The differential current gain obtained for a given sample of a
2N5089 NPN transistor would typically be about the same as the
DC current gain—about 500. Again, values could range from a low
of 300 to a high of 800 or so.
3.5.14Program 7 Description
After both units are returned to default conditions, SMUB is set
up as follows:
• Source V
• Local sense
• 100mA compliance
The collector-emitter voltage (VCE) will then be set. Then, the base
current will be set to the IB1 value and the collector current (IC1)
will be measured. Next, the base current will be set to the IB2
value and IC2 will be measured. The AC current gain of the device
will then be calculated and printed to the Instrument Console
window of TSB.
3.5.15Modifying Program 7
As with the DC current gain, AC current gain is often tested at
specific values of IC. Again, a search algorithm similar to the one
in Program 6A could be added to the program. Such an algorithm
would allow you to enter the desired collector current values, and
it would then perform an iterative search to determine automatically the two correct base current values that would result in the
desired collector currents.
3.6 Transistor Leakage Current
Leakage currents, such as ICEO (collector-base, emitter open) and
ICEO (collector-emitter, base open) can be tested using a singlechannel System SourceMeter instrument. The following paragraphs discuss ICEO tests and also include an example program for
making such tests.
3.6.1 Test Configuration
Figure 3-7 shows the basic test configuration for performing ICEO
tests. The SMU sources the collector-emitter voltage (VCEO) and
the instrument also measures ICEO. Often, VCEO is swept across
the desired range of values, and the resulting ICEO values can be
plotted against VCEO, as is the case with the example program
included in this section.
The base of the transistor should be left open. The same general
circuit configuration can be used to measure ICEO; connect the
SMU between the collector and base, and leave the emitter open
instead.
• Source I
• IV compliance, 1.1V range
• Local sense
SMUA is configured as follows:
3-10
Breakdown tests can also be performed using the same ICEO circuit
setup. In this case, the SMU is used to source I and measured
the breakdown voltage (V) in order to control device power at
breakdown better.
Section 3
Bipolar Transistor Tests
ICEO
Transistor
Under Test
Leave Base open
VCE
Test
Fixture
Series 2600
System
SourceMeter
Channel A
Source VCEO
Measure ICEO
I
V
Output LO
Figure 3-7. Configuration for ICEO tests
3.6.2Example Program 8: ICEO Test
Use Program 8 to run ICEO tests on bipolar transistors. Follow
these steps to run the program:
after the active prompt in the Instrument Console line
of TSB.
9. In the program ‘Iceo.tsp’, the function Iceo(vstart,
vstop, vsteps) is created.
1. With the power off, connect a dual-channel System SourceMeter instrument to the computer’s IEEE-488 interface.
• vstart represents the initial voltage value in the VCE sweep
2. Connect the test fixture to both units using appropriate
­cables.
• vsteps represents the number of steps in the sweep
3. Turn on the instrument and allow the unit to warm up for two
hours for rated accuracy.
4. Turn on the computer and start Test Script Builder (TSB). Once
the program has started, open a session by connecting to the
instrument. For details on how to use TSB, see the Series 2600
Reference Manual.
5. You can simply copy and paste the code from Appendix A in
this guide into the TSB script editing window (Program 8),
manually enter the code from the appendix, or import the TSP
file ‘Iceo.tsp’ after downloading it to your PC.
If your computer is currently connected to the Internet, you
can click on this link to begin downloading: http://www.
keithley.com/data?asset=50917.
6. Install a small-signal NPN silicon transistor such as a 2N3904
in the appropriate transistor socket of the test fixture.
7. Now, we must send the code to the instrument. The simplest
method is to right-click in the open script window of TSB,
and select ‘Run as TSP file’. This will compile the code and
place it in the volatile run-time memory of the instrument.
To store the program in non-volatile memory, see the “TSP
Programming Fundamentals” section of the Series 2600 Reference Manual.
8. Once the code has been placed in the instrument run-time
memory, we can run it at any time simply by calling the function ‘Iceo()’. This can be done by typing the text ‘Iceo()’
• vstop represents the final voltage value in the VCE sweep
If these values are left blank, the function will use the default
values given to the variables, but you can specify each variable
value by simply sending a number that is in-range in the function call. As an example, if you wanted to have the start voltage
be 1V, the stop value be 11V, and the number of steps be 20,
you would send Iceo(1, 11, 20) to the instrument.
10.The sources will be zeroed and then enabled. The program
will execute a voltage sweep on the collector-emitter and
measure the collector-emitter current (ICEO) at each point.
11.Once the measurements have completed, the data (VCE and ICE)
will be presented in the Instrument Console window of TSB.
3.6.3 Typical Program 8 Results
Figure 3-8 shows an example ICEO vs. VCEO plot generated by
Program 8. The device used for this example was a 2N3904 NPN
transistor.
3.6.4 Program 8 Description
The instrument is returned to default conditions. SMUA, which
sweeps VCEO and measures ICEO, is set up as follows:
• Source V
• Local sense
• 10mA compliance, autorange measure
• 1 NPLC Line cycle integration
3-11
Section 3
Bipolar Transistor Tests
ICEO vs. VCEO (2N3904)
3.50E–10
I CEO vs. VCEO
3.00E–10
I CEO (Amps)
2.50E–10
2.00E–10
1.50E–10
1.00E–10
5.00E–11
0.00E+00
0
2
4
6
8
10
VCEO (Volts)
Figure 3-8. Program 8 results: ICEO vs. VCEO
• vstart: 0V
3.6.5 Modifying Program 8
• vstop: 10V
• vsteps: 100
After setup, the output is zeroed and enabled. A linear voltage
sweep from the start to the stop value is performed. At each step,
the collector-emitter current (ICEO) is measured.
Upon sweep completion, the output is disabled and the data is
written to the Instrument Console window of TSB.
3-12
For different sweep values, simply modify the vstart, vstop,
and vstep values and source range parameter as appropriate.
In order to speed up the test procedure, you may wish to use
a faster integration period. Simply change the l _ nplc value.
Note, however, that changing this parameter may result in unacceptable reading noise.
Section 4
FET Tests
4.1 Introduction
FET tests discussed in this section include tests to generate
­common-source characteristic curves, and transconductance
tests. Example programs for each of these applications are also
included.
4.2 Instrument Connections
Two SMU channels are required for the tests and a dual-channel
instrument from the Series 2600 System SourceMeter line is recommended. A test fixture with safety interlock is recommended
for connections to the FET under test.
For general-purpose measurements with most of the Series 2600
instruments, Model 2600-BAN cables are recommended. For low
current tests (<1mA) or when using a low current instrument like
the Model 2636, Model 7078-TRX-3 triax cables are recommended
to make instrument-to-test fixture connections.
WARNING
Lethal voltages may be exposed when the test fixture lid is open. To avoid a possible shock hazard,
a safety interlock circuit must be connected before
use. Connect the fixture screw to safety earth
ground using #18 AWG minimum wire before use.
Turn off all power before connecting or disconnecting wires or cables
NOTES
Remote sensing connections are recommended for
optimum accuracy. See paragraph 1.2.2 for details.
If measurement noise is a problem, or for critical, low
level applications, use shielded cable for all signal
connections.
4.3 Common-Source
Characteristics
One of the more common FET tests involving family of curves
is common-source characteristics. Such tests are very similar to
the common-emitter characteristic tests outlined earlier except,
of course, for the fact that an FET rather than a bipolar transistor
is involved.
Test data for common-source characteristics are obtained by
sweeping the gate-source voltage (VGS) across the desired range of
values at specific increments. At each VGS value, the drain-source
voltage (V DS) is swept through the required range, once again at
the desired increments. At each V DS value, the drain current (ID)
is measured. Plots can then be made from this data to show ID vs.
V DS with one curve for each value of VGS.
4.3.1 Test Configuration
Figure 4-1 shows the test configuration for the common-source
tests. SMUB sweeps VGS, while SMUA sweeps V DS, and the instrument also measures ID. For this programming example, a smallsignal, N-channel FET such as a SD210 is recommended.
4.3.2Example Program 9:
Common-Source Characteristics
Program 9 outlines general programming techniques for measuring common-source characteristics. Follow these steps to use
this program:
1. With the power off, connect a dual-channel System SourceMeter instrument to the computer’s IEEE-488 interface.
2. Connect the test fixture to both units using appropriate
cables.
3. Turn on the instrument and allow the unit to warm up for two
hours for rated accuracy.
4. Turn on the computer and start Test Script Builder (TSB). Once
the program has started, open a session by connecting to the
instrument. For details on how to use TSB, see the Series 2600
Reference Manual.
5. You can simply copy and paste the code from Appendix A in
this guide into the TSB script editing window (Program 9),
manually enter the code from the appendix, or import the TSP
file ‘FET_Comm_Source.tsp’ after downloading it to your PC.
If your computer is currently connected to the Internet, you
can click on this link to begin downloading: http://www.
keithley.com/data?asset=50921.
4-1
Section 4
FET Tests
FET
Under Test
ID
Output HI
VDS
Output HI
Series 2600
System
SourceMeter
Channel B
Sweeps VGS
Test
Fixture
VGS
I
I
V
V
Series 2600
System
SourceMeter
Channel A
Sweeps VDS ,
Measures ID
Output LO
Output LO
Figure 4-1. Test configuration for common-source tests
6. Install an N-channel FET such as an SD210 in the appropriate
transistor socket of the test fixture.
7. Now, we must send the code to the instrument. The simplest
method is to right-click in the open script window of TSB,
and select ‘Run as TSP file’. This will compile the code and
place it in the volatile run-time memory of the instrument.
To store the program in non-volatile memory, see the “TSP
Programming Fundamentals” section of the Series 2600 Reference Manual.
8. Once the code has been placed in the instrument run-time
memory, we can run it at any time simply by calling the function ‘FET _ Comm _ Source()’. This can be done by typing
the text ‘FET _ Comm _ Source()’ after the active prompt
in the Instrument Console line of TSB.
9. In the program ‘FET_Comm_Source.tsp’, the function FET _
Comm _ Source(vgsstart, vgsstop, vgssteps,
vdsstart, vdsstop, vdssteps) is created.
the function call. As an example, if you wanted to have the
start voltages for VGS and V DS sweeps be 1V, the stop value
be 11V, and the number of steps be 20, you would send
FET _ Comm _ Source(1, 11, 20, 1, 11, 20) to
the instrument.
10.The sources will be zeroed and then enabled. The program
will execute a sweep of VGS values between 0V and 10V using
2V steps. At each VGS step, V DS will be stepped between 0V
and 10V at 0.1V increments. At each increment, ID will be
measured.
11.Once the measurements have been completed, the data (VGS,
V DS, and IDS) will be presented in the Instrument Console
window of TSB.
4.3.3 Typical Program 9 Results
Figure 4-2 shows a typical plot generated by example Program 9.
A 2N4392 N-channel JFET was used to generate these curves.
• vgsstart represents the initial voltage value in the
gate-source VGS sweep
4.3.4 Program 9 Description
• vgsstop represents the final voltage value in the gatesource VGS sweep
The unit is returned to default conditions. Next, SMUB, which
sweeps VGS, is programmed as follows:
• vgssteps represents the number of steps in the sweep
• Source V
• vdsstart represents the initial voltage value in the
drain-source V DS sweep
• 1mA compliance, 1mA range
• vdsstop represents the final voltage value in the drainsource V DS sweep
• vgsstart: 0V
• vdssteps represents the number of steps in the sweep
If these values are left blank, the function will use the default
values given to the variables, but you can specify each variable value by simply sending a number that is in-range in
4-2
• Local sense
• vgsstop: 10V
• vgssteps: 5
SMUA, which sweeps V DS and measures ID, is configured as
­follows:
Section 4
FET Tests
Common-Source Characteristics (SD210)
1.00E–01
8.00E–02
I DS (Amps)
VGS = 10V
6.00E–02
VGS = 7.5V
4.00E–02
VGS = 5V
2.00E–02
VGS = 2.5V
0.00E+00
0
1
2
3
4
5
6
7
8
9
10
VGS = 0V
VDS (Volts)
Figure 4-2. Program 9 results: Common-source characteristics
• Source V
4.4 Transconductance Tests
• Local sensing
• 100mA compliance, autorange measure
• vdsstart: 0V
• vdsstop: 10V
• vdssteps: 100
• 1 NPLC Line cycle integration
The forward transconductance (g fs) of an FET is usually measured at a specific frequency (for example, 1kHz). Such a test can
be simulated with DC values by using as small an incremental
change in DC parameters as possible. For example, assume that
we source two gate-source voltages, VGS1 and VGS2, and measure
two resulting drain currents, ID1 and ID2. The forward transconductance can then be approximated as follows:
Following setup of both units, the outputs are zeroed and
enabled. The first gate-source bias (VGS) source value is applied
and the drain-source voltage (V DS) sweep is started. At each point
in the V DS sweep, the drain current (ID) is measured. When the
final V DS value is reached, the drain-source voltage is returned
to 0V, the gate-source voltage (VGS) is incremented, and the V DS
sweep begins again.
∆ID
g = ____
fs ∆VGS
Upon reaching the final V DS value, the outputs are zeroed, disabled, and the data (VGS, V DS, and ID) is printed to the Instrument
Console Window of TSB, where it can be copied and pasted to a
spreadsheet for graphing.
Two common plots involving g fs include g fs vs. VGS and gfs vs. ID.
The programming examples included in this section demonstrate
how to generate g fs vs. VGS and g fs vs. ID plots.
4.3.5 Modifying Program 9
4.4.1 Test Configuration
For other VGS values, simply modify the vgsstart, vgsstop,
and vgssteps variables as required.
Figure 4-3 shows the general test configuration for transconductance tests. SMUB sweeps VGS, while SMUA sources V DS and also
measures ID. g fs values are computed from incremental changes in
ID and V DS. Note that an N-channel FET such as a SD210 is recommended for use with the example programs that follow.
Similarly, V DS can be swept over a different range by changing the
vdsstart, vdsstop, and vdsstep variables to the desired values.
where:gfs = forward transconductance (S)
∆ID = ID2 – ID1
∆VGS= VGS2 – VGS1
4-3
Section 4
FET Tests
FET
Under Test
ID
Output HI
VDS
Output HI
Series 2600
System
SourceMeter
Channel B
Sweeps VGS
VGS
I
V
Test
Fixture
I
V
Series 2600
System
SourceMeter
Channel A
Sources VDS ,
Measures ID
Output LO
Output LO
Figure 4-3. Configuration for transductance tests
4.4.2Example Program 10:
Transconductance vs.
Gate Voltage Test
Use Program 10 to generate a typical gfs vs. VGS plot as well as a
gfs vs. ID.
1. With the power off, connect a dual-channel System SourceMeter instrument to the computer’s IEEE-488 interface.
2. Connect the test fixture to both units using appropriate
­cables.
3. Turn on the instrument and allow the unit to warm up for two
hours for rated accuracy.
4. Turn on the computer and start Test Script Builder (TSB). Once
the program has started, open a session by connecting to the
instrument. For details on how to use TSB, see the Series 2600
Reference Manual.
5. You can simply copy and paste the code from Appendix A in
this guide into the TSB script editing window (Program 10),
manually enter the code from the appendix, or import the TSP
file ‘Transconductance.tsp’ after downloading it to your PC.
If your computer is currently connected to the Internet, you
can click on this link to begin downloading: http://www.
keithley.com/data?asset=50916.
6. Install an N-channel FET such as an SD210 in the appropriate
transistor socket of the test fixture.
7. Now, we must send the code to the instrument. The simplest
method is to right-click in the open script window of TSB, and
select ‘Run as TSP file’. This will compile the code and place
it in the volatile run-time memory of the instrument. To store
the program in non-volatile memory, see the “TSP Program-
4-4
ming Fundamentals” section of the Series 2600 Reference
Manual.
8. Once the code has been placed in the instrument run-time
memory, we can run it at any time simply by calling the function ‘Transconductance()’. This can be done by typing
the text ‘Transconductance()’ after the active prompt in
the Instrument Console line of TSB.
9. In the program ‘Transconductance.tsp’, the function
Transconductance(vgsstart, vgsstop,
vgssteps, vdsbias) is created.
• vgsstart represents the initial voltage value in the
gate-source VGS sweep
• vgsstop represents the final voltage value in the gatesource VGS sweep
• vgssteps represents the number of steps in the sweep
• vdsbias represents the voltage value applied to the
drain-source terminal of the FET
If these values are left blank, the function will use the default
values given to the variables, but you can specify each variable
value by simply sending a number that is in-range in the function call. As an example, if you wanted to have the start voltages for VGS sweeps be 1V, the stop value be 11V, the number
of steps be 20, and the V DS value as 5V, you would send
­Transconductance(1, 11, 20, 5) to the instrument.
10.The sources will be zeroed and then enabled. The instrument
will apply V DS and execute a sweep of VGS values between
0V and 5V using 100 steps. At each increment, ID will be
­measured.
Section 4
FET Tests
11.Once the measurements have completed, the data (VGS, V DS, ID,
and gfs) will be presented in the Instrument Console window
of TSB.
4.4.3 Typical Program 10 Results
Figure 4-4 shows a typical gfs vs. VGS plot as generated by the
example program. Again, an SD210 N-channel FET was used for
the example plot.
Figure 4-5 shows a typical gfs vs. ID plot generated by the example
program.
4.4.4 Program 10 Description
The instrument is returned to default conditions. SMUB, which
sweeps VGS, is programmed as follows:
•
•
•
•
•
•
Source V
1mA compliance, autorange
Local sense
vgsstart: 0V
vgsstop: 5V
vgssteps: 100
gfs vs. VGS (SD210)
1.00E–02
VDS = 10V
gfs (Siemens)
8.00E–03
6.00E–03
4.00E–03
2.00E–03
0.00E–00
0
1
2
3
4
5
VGS (Volts)
Figure 4-4. Program 10 results: Transconductance vs. VGS
gfs vs. ID (SD210)
1.00E–02
VDS = 10V
gfs (Siemens)
8.00E–03
6.00E–03
4.00E–03
2.00E–03
0.00E–00
0.000
0.005
0.010
0.015
0.020
0.025
0.030
I D (Amps)
Figure 4-5. Program 10 results: Transconductance vs. ID
4-5
Section 4
FET Tests
SMUA, which sources V DS and measures ID, is then configured in
the following manner:
• Source V
• Local sense
• 100mA compliance, autorange measure
4.5.1 Search Method Test Configuration
Figure 4-6 shows the general test configuration for the search
method threshold voltage tests. SMUB sources VGS, while SMUA
sources V DS and also measures ID. An iterative search process is
included in the program to allow you to enter a target ID value.
4.5.2Example Program 11A: Threshold
Voltage Tests Using Search Method
• 1 NPLC Line cycle integration
• vdsbias:10V
Following setup of both units, the outputs are zeroed and
enabled. SMUA applies the V DS bias, and SMUB begins the VGS
voltage sweep. At each step in the VGS sweep, SMUA measured
the drain current (ID). The process repeats until all points in the
sweep have been taken.
Next, we encounter the part of the program where the transconductance values are calculated. Each transconductance value is
computed from ∆ID and ∆VGS. Finally, the data (VGS, ID, and gfs) is
printed to the Instrument Console of TSB. You can then copy and
paste the data to a spreadsheet to graph gfs vs. VGS and gfs vs. ID.
4.5 Threshold Tests
The threshold voltage (V T ) is a critical parameter for FET characterization, as well as process control. Basically, there are a number
of methods for determining V T, including several transconductance methods, the two-point extrapolated V T method, as well as
the V T @ ID search method. In this paragraph, we will discuss the
ID search method for finding V T, along with a self-biasing method
that takes advantage of the special capabilities of the Series 2600
System SourceMeter instruments.
Use Program 11A to perform the V T test using the search for target
ID method.
1. With the power off, connect a dual-channel System SourceMeter instrument to the computer’s IEEE-488 interface.
2. Connect the test fixture to both units using appropriate
­cables.
3. Turn on the instrument and allow the unit to warm up for two
hours for rated accuracy.
4. Turn on the computer and start Test Script Builder (TSB). Once
the program has started, open a session by connecting to the
instrument. For details on how to use TSB, see the ­Series 2600
Reference Manual.
5. You can simply copy and paste the code from Appendix A in
this guide into the TSB script editing window (Program 11A),
manually enter the code from the appendix, or import the TSP
file ‘FET_Thres_Search.tsp’ after downloading it to your PC.
If your computer is currently connected to the Internet, you
can click on this link to begin downloading: http://www.
keithley.com/data?asset=50919.
6. Install an N-hannel FET such as an SD210 in the appropriate
transistor socket of the test fixture.
FET
Under Test
ID
Output HI
VDS
Output HI
Series 2600
System
SourceMeter
Channel B
Sets VGS for
Target ID
VGS
I
V
Output LO
Figure 4-6. Configuration for search method threshold tests
4-6
Test
Fixture
I
V
Series 2600
System
SourceMeter
Channel A
Sources VDS ,
Measures ID
Output LO
Section 4
FET Tests
7. Now, we must send the code to the instrument. The simplest
method is to right-click in the open script window of TSB,
and select ‘Run as TSP file’. This will compile the code and
place it in the volatile run-time memory of the instrument.
To store the program in non-volatile memory, see the “TSP
Programming Fundamentals” section of the Series 2600 Reference Manual.
• 1mA compliance, autorange
• Local sense
SMUA, which sources V DS and measures ID, is then configured in
the following manner:
• Source V
8. Once the code has been placed in the instrument run-time
memory, we can run it at any time simply by calling the function ‘FET _ Thres _ Search()’. This can be done by
typing the text ‘FET _ Thres _ Search()’ after the active
prompt in the Instrument Console line of TSB.
• Local sense
9. In the program ‘FET_Thres_Search.tsp’, the function FET _
Thres _ Search(vdssource, lowvgs, highvgs,
targetid) is created.
Once the SMU channels have been configured, the sources values
are programmed to 0 and the outputs are enabled. The drainsource voltage (V DS) is sourced, compliance is checked with the
function Check _ Comp(), and the program enters into the
binary search algorithm for the target drain current (ID) by varying
the gate-source voltage (VGS) value, measuring the ID, comparing it
to the target ID, and adjusting the VGS value, if necessary. The iteration counter is incremented each cycle through the algorithm. If
the number of iterations has been exceeded, a message to that
effect is displayed, and the program halts.
• vdssource represents the voltage value on the drainsource of the transistor
• lowvgs represents the gate-source voltage low limit for
the search algorithm
• highvgs represents the gate-source voltage high limit
for the search algorithm
• targetid represents the target drain current for the
search algorithm
If these values are left blank, the function will use the default
values given to the variables, but you can specify each variable value by simply sending a number that is in-range in the
function call. As an example, if you wanted to have the drainsource voltage (V DS) be 2.5V, the gate-source voltage low value
at 0.7V, the gate-source voltage high value at 1.5V, and the
target drain current at 2µA, you would send FET _ Thres _
Search(2.5, 0.7, 1.5, 2E-6) to the instrument.
10.The sources will be enabled, and the collector current of
the device will be measured. The program will perform an
iterative search to determine the closest match to the target
ID (within ±5%). If the search is unsuccessful, the program
will print “Iteration Level Reached”. This is an error indicating
that the search reached its limit. Recheck the connections,
DUT, and variable values to make sure they are appropriate
for the device.
11.Once the sweep has been completed, the data (ID, VGS, and
V DS) will be presented in the Instrument Console window
of TSB.
4.5.3 Program 11A Description
Initially, the instrument is returned to default conditions. SMUB,
which sources VGS, is programmed as follows:
• Source V
• 100mA compliance, autorange measure
• 1 NPLC Line cycle integration
Assuming that the number of iterations has not been exceeded, the
data is displayed in the Instrument Console window of the TSB.
4.5.4 Modifying Program 11A
As written, the program sets the number of iterations to search for
target ID to 20. You can change this by adjusting the l _ k _ max
variable to perform the iterative search as many times as is necessary. Similarly, the allowed range for the ID target search is ±5%.
Again, you can make this tolerance range as tight as necessary
by modifying the limits in line 155. Note that reducing the target
range will probably require an increase in the number of iterations as well.
4.5.5 Self-bias Threshold Test
Configuration
Figure 4-7 shows the general test configuration for the selfbias method of threshold voltage tests. SMUB sources the drain
current (assumed to be the same as the source current), and it
also measures the threshold voltage, V T. SMUA sources V DS. This
arrange­ment allows very rapid threshold voltage measurement
(milli­seconds per reading) at very low currents, and it can be used
with both enhancement-mode and depletion-mode FETs. Note
that the high impedance sensing circuits and the floating capabilities of the Series 2600 System SourceMeter instruments are key
characteristics that allow this special configuration to be used.
4-7
Section 4
FET Tests
2. Connect the test fixture to both units using appropriate cables.
Note that OUTPUT HI of SMUA is connected to the OUTPUT
LO of SMUB, while SENSE HI of SMUA is connected to the
OUTPUT HI of SMUB.
WARNING
When a System SourceMeter instrument is programmed for remote sensing, hazardous voltage
may be present on the SENSE and OUTPUT terminals when the unit is in operate regardless of the
programmed voltage or current. To avoid a possible shock hazard, always turn off power before
connecting or disconnecting cables to the Source­Measure Unit or the associated test fixture.
3. Turn on the instrument and allow the unit to warm up for two
hours for rated accuracy.
4. Turn on the computer and start Test Script Builder (TSB). Once
the program has started, open a session by connecting to the
instrument. For details on how to use TSB, see the ­Series 2600
Reference Manual.
NOTE
Entered values for both V DS and ID are adjusted to the
reverse polarity because of the connection configuration used. For example, for an N-channel FET, both V DS
and ID must be negative.
5. You can simply copy and paste the code from Appendix A in
this guide into the TSB script editing window (Program 11B),
manually enter the code from the appendix, or import the TSP
file ‘FET_Thres_Fast.tsp’ after downloading it to your PC.
As an example, entering a V DS of 5V will result in –5V
actually being applied at the output.
If your computer is currently connected to the Internet, you
can click on this link to begin downloading from http://www.
keithley.com/data?asset=50920.
These values will result in proper biasing of the
DUT. Also, the sign of the measured V T value will be
reversed.
6. Install an NPN FET such as a SD210 in the appropriate transistor socket of the test fixture.
4.5.6Example Program 11B: Self-bias
Threshold Voltage Tests
Use Program 11B to perform the self-bias threshold voltage test.
1. With the power off, connect a dual-channel System SourceMeter instrument to the computer’s IEEE-488 interface.
7. Now, we must send the code to the instrument. The simplest
method is to right-click in the open script window of TSB,
and select ‘Run as TSP file’. This will compile the code and
place it in the volatile run-time memory of the instrument.
To store the program in non-volatile memory, see the “TSP
Programming Fundamentals” section of the Series 2600 Reference Manual.
FET
Under Test
D
G
Sense LO
S
V
Output HI
Series 2600
System
SourceMeter
Channel B
Sources ID (= IS)
Measures VT
I
V
Output LO
Figure 4-7. Configuration for self-bias threshold tests
4-8
Output LO
Test
Fixture
Sense HI
Series 2600
System
SourceMeter
Channel A
Sources VDS
Output HI
Section 4
FET Tests
8. Once the code has been placed in the instrument run-time
memory, we can run it at any time simply by calling the function ‘FET_Thres_Fast()’. This can be done by typing the text
‘FET _ Thres _ Fast()’ after the active prompt in the
Instrument Console line of TSB.
9. In the program ‘FET_Thres_Fast().tsp’, the function FET _
Thres _ Fast(vdssource, istart, istop,
isteps) is created.
• Source I
• 11V compliance, autorange
• Local sense
• 1 NPLC integration rate
• istart: 0.5µA
• istop: 1µA
• vdssource represents the voltage value on the drainsource of the transistor
• isteps: 10
• istart represents the start value for the drain current
sweep
Next, SMUA, which sources V DS, is configured in the following
manner:
• istop represents the stop value for the drain current
sweep
• Source V
• isteps represents the number of steps in the current
sweep
• Remote sensing
If these values are left blank, the function will use the default
values given to the variables, but you can specify each variable
value by simply sending a number that is in-range in the function call. As an example, if you wanted to have the drain-source
voltage (V DS) be 0.25V, the drain current sweep start value at
0.20µA, the drain current sweep stop value at 2µA, and the
number of steps be 15, you would send FET _ Thres _
Fast(0.25, 200E-9, 2E-6, 15) to the instrument.
• vdssource: 0.5V
10.The sources will be enabled, and the collector current of the
device will be measured.
11.Once the sweep has been completed, the data (V DS, V T, and ID)
will be presented in the Instrument Console window of TSB.
Note that the program reverses the polarity of the emitter currents in order to display true polarity.
4.5.7 Program 11B Description
Initially, the instrument is returned to default conditions. Next,
SMUB, which sources ID and measures V T, is programmed as
­follows:
• 100mA compliance, autorange
Once the SMU channels have been configured, the sources values
are programmed to 0 and the outputs are enabled. The drainsource voltage (V DS) is sourced and the drain current (ID) is
swept. At each point in the sweep, the threshold voltage (V T) is
­measured.
The data is displayed in the Instrument Console window of the
TSB.
Note that both ID and V T values are corrected for proper polarity.
4.5.8 Modifying Program 11B
As written, the program tests for threshold voltages at 10 values
of ID between 0.5µA and 1µA in 10 increments. These values can
be changed to the required values simply by modifying the corresponding variables in the program.
4-9
Section 4
FET Tests
4-10
Section 5
Using Substrate Bias
5.1 Introduction
To this point in this guide, we have focused on performing tests on
devices that do not require substrate bias. Because many devices,
especially those in complex packages, do require some form of
substrate bias, our discussion would not be complete without discussing methods for applying and programming substrate bias.
In the following paragraphs, we will discuss applying substrate bias
by adding another Series 2600 System SourceMeter instrument.
5.2 Substrate Bias Instrument
Connections
WARNING
Interlock circuits must be connected before use.
Connect the fixture ground to safety earth ground
using #18 AWG minimum wire before use. Turn off
all power before connecting or disconnecting wires
or cables.
interface known as TSP-Link™ interface. TSP-Link allows expanding
test systems to include up to 16 TSP-Link enabled instruments.
In a TSP-Link-enabled system, one of the nodes (instruments) is
the master, which is generally denoted as Node 1, while the other
nodes in the system are slaves. One GPIB connection is required
to link the controlling PC and the master instrument. All other
master/slave connections require a simple TSP-Link connection
using a crossover Ethernet cable. Additional instruments can
be connected as slaves by simply connecting each slave to one
another serially using additional crossover Ethernet cables and
configuring each instrument for use as a TSP-Link node.
More information on TSP-Link features can be found in the Series
2600 System SourceMeter Reference Manual.
CPU with
GPIB
5.2.1 Source-Measure Unit Substrate
Bias Connections and Setup
Figure 5-1 shows test connections when using two Series 2600
System SourceMeter instruments because the tests outlined in the
following sections require three SMUs. Two SMUs supply the same
functions as outlined earlier in this guide, and a third SMU is used
to apply substrate bias. In the past, this would have required connecting and coordinating three separate instruments, each with
only one SMU.
To simplify hardware integration, the Keithley Series 2600 System
SourceMeter instruments are equipped with a few features that
make the task of multi-channel testing much easier. For example,
we can use a dual-channel instrument such as the Keithley Model
2602, 2612, or 2636 and a single-channel Instrument such as the
Model 2601, 2611, or 2635. Therefore, we need only two instruments to perform the test. All of the following programs will also
work using two dual-channel instruments with no modification.
For instrument-to-instrument communication, Keithley’s Series
2600 System SourceMeter instruments employ an expansion
GPIB Cable
Series 2600
System
SourceMeter
Node 1: Master
TSP-Link Cable
Series 2600
System
SourceMeter
Node 2: Slave
Figure 5-1. TSP-Link connections for two instruments
5-1
Section 5
Using Substrate Bias
A test fixture with appropriate shielding and safety interlock
mechanisms is recommended for test connections, along with
Model 7078-TRX-3 triax cables for low current measurements.
Note that the connecting cables to the second instrument, assume
that local sensing will be used even though that may not be the
situation in many cases.
5.2.2 Voltage Source Substrate Bias
Connections
Figure 5-2 shows bias connections using a single-channel Model
2635 Low Current System SourceMeter instrument for substrate
bias connections. Two additional SMU channels are added using
a dual-channel Model 2602 System SourceMeter instrument. Note
that remote sensing is not used in this application; remote sensing
could be added by connecting the sense terminals of the Model
2635 to the sense connections on the test fixture and adding additional remote sense commands to the program.
NOTES
If measurement noise is a problem or for critical, low
level applications, use shielded cable for all signal
connections.
5.3 Source-Measure Unit
Substrate Biasing
The following paragraphs discuss using three SMU channels to
provide substrate biasing: a dual-channel instrument, such as a
Model 2602 or 2636, and a single-channel instrument, such as
a 2601 or 2635. All of the example programs will work with two
dual-channel instruments with no modification.
In the first example, the substrate current (ISB) is measured as the
gate-source voltage (VGS) is swept across the desired range. The
program generates a plot of ISB vs. VGS. In the second example, the
third SMU channel provides substrate bias for common-source
characteristic tests.
5.3.1 Program 12 Test Configuration
Remote sensing connections are recommended for
optimum accuracy. See paragraph 1.2.2 for details.
CPU with
GPIB
Figure 5-3 shows the test configuration for Program 12. SMUB of
Node 1 is used to sweep VGS, while SMUA of Node 1 sources V DS.
SMUA of Node 2 applies a user-defined substrate bias (VSB) to the
device under test: it also measures the substrate current (ISB).
5.3.2Example Program 12: Substrate
Current vs. Gate-Source Voltage
Program 12 demonstrates methods to generate an ISB vs. VGS plot.
Follow these steps to use this program.
GPIB Cable
Model 2602
Dual-Channel
System
SourceMeter
Node 1: Master
2. Connect the test fixture to both units using appropriate
­cables.
3. Turn on the instruments and allow the units to warm up for
two hours for rated accuracy.
TSP-Link Cable
Model 2635
Low Current
System
SourceMeter
Node 2: Slave
Figure 5-2. TSP-Link instrument connections
5-2
1. With the power off, connect the dual-channel Instrument to
the computer’s IEEE-488 interface. Connect the single-channel
Instrument to the dual-channel master using a crossover Ethernet cable.
4. Configure the TSP-Link communications for each instrument.
Slave: A single-channel instrument such as the Model 2601,
2611, or 2635.
1. Press the MENU key to access MAIN MENU.
2. Select the COMMUNICATION menu. (Skip this step if the
Series 2600 instruments used have firmware Revision 1.4.0
or later installed.)
Section 5
Using Substrate Bias
FET
Under Test
ID
Test
Fixture
VGS
Output HI
Series 2600
System
SourceMeter
Channel B
Node 1
Sweeps VGS
VDS
Output HI
I
I
V
V
Output LO
Series 2600
System
SourceMeter
Channel A
Node 2
Sources VSB
Measures ISB
Output LO
Output HI
I
V
Series 2600
System
SourceMeter
Channel A
Node 1
Sources VDS
Measures ID
Output LO
Figure 5-3. Program 12 test configuration
3. Select the TSPLINK_CFG menu. (If the Series 2600 instruments used have firmware Revision 1.4.0 or later installed,
the menu name should be TSPLINK.)
4. Select the NODE menu.
5. Set the NODE number to 2 and press ENTER.
Master: A dual-channel instrument such as the Model 2602,
2612, or 2636.
1. Press the MENU key to access MAIN MENU.
2. Select the COMMUNICATION menu. (Skip this step if
the Series 2600 instruments used have firmware Revision
1.4.0 or later installed.)
3. Select the TSPLINK_CFG menu. (If the Series 2600
instruments used have firmware Revision 1.4.0 or later
installed, the menu name should be TSPLINK.)
4. Select the NODE menu.
5. Set the NODE number to 1 for the master and press
ENTER.
6. Select the TSPLINK_CFG menu. (If the Series 2600
instruments used have firmware Revision 1.4.0 or later
installed, the menu name should be TSPLINK.)
7. Select the RESET to initialize the TSP-Link.
5. Turn on the computer and start Test Script Builder (TSB).
Once the program has started, open a session by connecting
to the master instrument. For details on how to use TSB, see
the Series 2600 Reference Manual.
6. You can simply copy and paste the code from Appendix A in
this guide into the TSB script editing window (Program 12),
manually enter the code from the appendix, or import the TSP
file ‘FET_Isb_Vgs.tsp’ after downloading it to your PC.
If your computer is currently connected to the Internet, you
can click on the following link to begin downloading: http://
www.keithley.com/data?asset=50964.
7. Install an NPN FET such as a SD210 in the appropriate transistor socket of the test fixture.
8. Now, we must send the code to the instrument. The simplest
method is to right-click in the open script window of TSB and
select ‘Run as TSP file’. This will compile the code and place
it in the volatile run-time memory of the instrument. To store
the program in non-volatile memory, see the “TSP Programming Fundamentals” section of the Series 2600 Reference
Manual.
9. Once the code has been placed in the instrument run-time
memory, we can run it at any time simply by calling the function ‘FET_Isb_Vgs()’. This can be done by typing the text
‘FET _ Isb _ Vgs()’ after the active prompt in the Instrument Console line of TSB.
10.In the program ‘FET_Isb_Vgs().tsp’, the function FET _ Isb _
Vgs(vdssource, vsbsource,vgsstart,vgsstop,
vgssteps) is created.
• vdssource represents the voltage value on the drainsource of the transistor
• vsbsource represents the voltage value on the
substrate-source of the transistor
5-3
Section 5
Using Substrate Bias
• Local sense
• vgsstart represents the start value for the gate-source
voltage sweep
• vgsstart: 0V
• vgsstop represents the stop value for the gate-source
voltage sweep
• vgsstop: 10V
• vgssteps represents the number of steps in the sweep
• vgssteps: 10
If these values are left blank, the function will use the default
values given to the variables, but you can specify each variable value by simply sending a number that is in range in the
function call. As an example, if you wanted the drain-source
voltage (V DS) to be 2V, substrate-source (VSB) to be –2V, the
gate-source (VGS) voltage sweep start value at 1V, the gatesource sweep stop value at 12V, and the number of steps to
be 15, you would send FET _ Isb _ Vgs(2, -2, 1, 12,
15) to the instrument.
Next, Node 1 SMUA, which sources V DS, is set up to operate in the
following manner:
11.The sources will be enabled, and the gate-source voltage
sweep will be executed.
Finally, Node 2 SMUA, which sources VSB and measures ISB, is programmed as follows:
12.Once the sweep has been completed, the data (ID, VGS, and ISB)
will be presented in the Instrument Console window of TSB.
• Source V
5.3.3 Typical Program 12 Results
• Source V
• Local sensing
• 100mA compliance, autorange
• vdssource: 1V
• Local sensing
• 1 compliance, autorange measure
Figure 5-4 shows a typical plot generated by example Program 12
using an SD210 MOSFET.
5.3.4 Program 12 Description
After the SMUs are returned to default conditions, Node 1 SMUB,
which sweeps VGS, is configured as follows:
• Source V
• 1 NPLC Line cycle integration
After both instruments are set up, the outputs are zeroed and
enabled. The bias values VSB and V DS are applied, then the VGS
sweep begins. At each point in the sweep, the drain current (ID)
and substrate leakage (ISB) are measured.
After the sweep is complete, the data (ID, VGS, and ISB) is printed to
the Instrument Console of TSB.
• 1µA compliance, autorange
ISB vs. VGS
0.00E+00
–5.00E–13
I SB (Amps)
–1.00E–12
–1.50E–12
–2.00E–12
–2.50E–12
–3.00E–12
Series 1
–3.50E–12
0
2
4
6
VGS (Volts)
Figure 5-4. Program 12 typical results: ISB vs. VGS
5-4
8
10
12
Section 5
Using Substrate Bias
5.3.5 Modifying Program 12
3. Turn on the instruments and allow the units to warm up for
two hours for rated accuracy.
For different sweeps, the variables for VGS start, VGS stop, and
VGS step values can be changed as required. For different sweep
lengths, array size and loop counter values must be adjusted
accordingly. You can also change the V DS value, if desired, by
modifying that parameter accordingly.
4. Configure the TSP-Link communications for each instrument.
Slave: A single-channel instrument such as the Model 2601,
2611, or 2635.
1. Press the MENU key to access MAIN MENU.
2. Select the COMMUNICATION menu. (Skip this step if the
Series 2600 instruments used have firmware Revision 1.4.0
or later installed.)
5.3.6 Program 13 Test Configuration
Figure 5-5 shows the test configuration for Program 13. Unit #1
is used to sweep VGS; Unit #2 sweeps V DS and measures ID. Unit
#3 applies a user-defined substrate bias to the device under test.
Common source characteristics are generated by data taken when
the program is run.
3. Select the TSPLINK_CFG menu. (If the Series 2600 instruments used have firmware Revision 1.4.0 or later installed,
the menu name should be TSPLINK.)
4. Select the NODE menu.
5.3.7Example Program 13:
Common-Source Characteristics
with Source-Measure Unit
Substrate Bias
5. Set the NODE number to 2 and press ENTER.
Program 13 demonstrates common-source characteristic test
pro­gram­ming with substrate bias. Follow these steps to use this
­program.
2. Select the COMMUNICATION menu. (Skip this step if
the Series 2600 instruments used have firmware Revision
1.4.0 or later installed.)
1. With the power off, connect the dual-channel SourceMeter
instrument to the IEEE-488 interface of the computer. Connect the ­single-channel SourceMeter instrument to the dualchannel ­master using a crossover Ethernet cable.
3. Select the TSPLINK_CFG menu. (If the Series 2600
instruments used have firmware Revision 1.4.0 or later
installed, the menu name should be TSPLINK.)
4. Select the NODE menu.
2. Connect the test fixture to both units using appropriate
­cables.
5. Set the NODE number to 1 for the master and press
ENTER.
Master: A dual-channel instrument such as the Model 2602,
2612, or 2636.
1. Press the MENU key to access MAIN MENU.
FET
Under Test
ID
Test
Fixture
VGS
Output HI
Series 2600
System
SourceMeter
Channel B
Node 1
Sweeps VGS
VDS
Output HI
I
I
V
V
Series 2600
System
SourceMeter
Channel A
Node 2
Sources
Substrate Bias
Output LO
Output LO
Output HI
I
V
Series 2600
System
SourceMeter
Channel A
Node 1
Sweeps VDS
Measures ID
Output LO
Figure 5-5. Program 13 test configuration
5-5
Section 5
Using Substrate Bias
6. Select the TSPLINK_CFG menu. (If the Series 2600
instruments used have firmware Revision 1.4.0 or later
installed, the menu name should be TSPLINK.)
function ‘FET_Comm_Source_Vsb()’. This can be done by
typing the text ‘FET _ Comm _ Source _ Vsb()’ after the
active prompt in the Instrument Console line of TSB.
9. In the program ‘FET_Comm_Source_Vsb().tsp’, the function
FET _ Comm _ Source _ Vsb(vgsstart, vgsstop,
vgssteps, vdsstart, vdsstop, vdssteps,
vsbsource) is created.
­
7. Select the RESET to initialize the TSP-Link.
5. Turn on the computer and start Test Script Builder (TSB).
Once the program has started, open a session by connecting
to the master instrument. For details on how to use TSB, see
the Series 2600 Reference Manual.
• vgsstart represents the start value for the gate-source
voltage sweep
You can simply copy and paste the code from Appendix A in
this guide into the TSB script editing window (Program 13),
manually enter the code from the appendix, or import the
TSP file ‘FET_Comm_Source_Vsb.tsp’ after downloading it to
your PC.
• vgsstop represents the stop value for the gate-source
voltage sweep
• vgssteps represents the number of steps in the sweep
• vdsstart represents the start value for the drain-source
voltage sweep
If your computer is currently connected to the Internet, click
on the following link to begin downloading: http://www.
keithley.com/data?asset=50921.
• vdsstop represents the stop value for the drain-source
voltage sweep
6. Install an NPN FET such as an SD210 in the appropriate transistor socket of the test fixture.
• vdssteps represents the number of steps in the sweep
7. Now, we must send the code to the instrument. The simplest
method is to right-click in the open script window of TSB and
select ‘Run as TSP file’. This will compile the code and place
it in the volatile run-time memory of the instrument. To store
the program in non-volatile memory, see the “TSP Programming Fundamentals” section of the Series 2600 Reference
Manual.
If these values are left blank, the function will use the default
values given to the variables, but you can specify each variable value by simply sending a number that is in-range in the
function call. As an example, if you wanted to have the gatesource (VGS) voltage sweep start value at 1V, the gate-source
sweep stop value at 12V and the number of steps to be 10,
the drain-source (V DS) voltage sweep start value at 1V, the
drain-source sweep stop value at 12V and the number of steps
to be 80, and the substrate bias to be –2V, you would send
• vsbsource represents the substrate bias voltage
8. Once the code has been placed in the instrument run-time
memory, we can run it at any time simply by calling the
Common-Source Characteristics
with Substrate Bias (SD210)
1.00E–01
I DS (Amps)
8.00E–02
VGS = 10V
6.00E–02
VGS = 7.5V
4.00E–02
VGS = 5V
2.00E–02
0.00E+00
0
1
2
3
4
5
6
7
8
9
10
VGS = 2.5V
VGS = 0V
VDS (Volts)
Figure 5-6. Program 13 typical results: Common-source characteristics with substrate bias
5-6
Section 5
Using Substrate Bias
FET _ Comm _ Source _ Vsb(1, 12, 10, 1, 12,
80, –2) to the instrument.
10.The sources will be enabled, and the substrate bias is applied,
the gate-source voltage value is applied, and the drain-source
sweep is executed. The gate-source voltage value is then incremented and the drain-source sweep is re-run.
11.Once the gate-source sweep has been completed, the data
(VSB, VGS, V DS, and ID) will be presented in the Instrument
Console window of TSB.
5.3.8 Typical Program 13 Results
Figure 5-6 shows a typical plot generated by Example
Program 13.
5.3.9 Program 13 Description
Both instruments are returned to default conditions. Node 1
SMUB, which sweeps VGS, is configured as follows:
• Source V
• 1mA compliance, autorange
• Local sense
• vgsstart: 0V
• vgsstop: 10V
• vgssteps: 5
Next, Node 1 SMUA, which sweeps V DS and measures ID, is set up
to operate in the following manner:
• Source V
• Local sensing
• 100mA compliance, autorange measure
• 1 NPLC Line cycle integration
• vdsstart: 0V
• vdsstop: 10V
• vdssteps: 100
Finally, Node 2 SMUA, which provides substrate bias, is programmed as follows:
• Source V
• Local sensing
required values, and measuring ID at each step along the way. The
program then loops back for the next sweep until all five sweeps
have been performed.
Next, all three SMU outputs are zeroed and disabled. Finally, the
data is written to the Instrument Console of the TSB.
5.3.10Modifying Program 13
For different sweeps, the VGS start, VGS stop, VGS steps, V DS start,
V DS stop, and V DS steps values can be changed as required. For
different sweep lengths, array size and loop counter values must
be adjusted accordingly.
5.4 BJT Substrate Biasing
The following paragraphs discuss using one dual-channel and
one single-channel Series 2600 System SourceMeter instrument
to perform tests on a four-terminal device, such as a BJT, with
substrate bias. The example shown in this section is a modified
version of the common-emitter BJT test presented previously in
the guide.
5.4.1 Program 14 Test Configuration
Figure 5-7 shows the test configuration for Program 14. Node 1
SMUB is used to sweep IB, while Node 1 SMUA sweeps VCE and
measures IC. Node 2 SMUA applies the substrate bias (VSB) to the
device under test.
5.4.2Example Program 14: CommonEmitter Characteristics with a
Substrate Bias
Program 14 demonstrates common-emitter characteristic test programming with substrate bias. Proceed as follows:
1. With the power off, connect the dual-channel System SourceMeter instrument to the computer’s IEEE-488 interface. Connect the single-channel System SourceMeter instrument to the
dual-channel master using a crossover Ethernet cable.
2. Connect the test fixture to both units using appropriate
­cables.
• 10mA compliance, autorange measure
3. Turn on the instruments and allow the units to warm up for
two hours for rated accuracy.
Both instruments are returned to default conditions; the sources
are zeroed and enabled. The substrate bias (VSB) and gate-source
(VGS) are applied and the program enters the main program loop
to perform five ID vs. V DS sweeps, one for each of five VGS values.
Node 1 SMUA then cycles through its sweep list, setting V DS to the
4. Configure the TSP-Link communications for each instrument.
Slave: A single-channel instrument such as the Model 2601,
2611, or 2635.
1. Press the MENU key to access MAIN MENU.
5-7
Section 5
Using Substrate Bias
Transistor
Under Test
IC
Test
Fixture
VCE
Output HI
Series 2600
System
SourceMeter
Channel B
Node 2
Sweeps IB
I
V
Output LO
Output HI
V
Series 2600
System
SourceMeter
Channel A
Node 1
Sources
Substrate Bias
Output LO
Output HI
I
V
Series 2600
System
SourceMeter
Channel A
Node 1
Sweeps VCE
Measures IC
Output LO
Figure 5-7. Program 14 test configuration
2. Select the COMMUNICATION menu. (Skip this step if the
Series 2600 instruments used have firmware Revision 1.4.0
or later installed.)
3. Select the TSPLINK_CFG menu. (If the Series 2600 instruments used have firmware Revision 1.4.0 or later installed,
the menu name should be TSPLINK.)
4. Select the NODE menu.
5. Set the NODE number to 2 and press ENTER.
Master: A dual-channel instrument such as the Model 2602,
2612, or 2636.
1. Press the MENU key to access MAIN MENU.
2. Select the COMMUNICATION menu. (Skip this step if
the Series 2600 instruments used have firmware Revision
1.4.0 or later installed.)
3. Select the TSPLINK_CFG menu. (If the Series 2600
instruments used have firmware Revision 1.4.0 or later
installed, the menu name should be TSPLINK.)
4. Select the NODE menu.
5. Set the NODE number to 1 for the master and press
ENTER.
6. Select the TSPLINK_CFG menu. (If the Series 2600 instruments used have firmware Revision 1.4.0 or later installed,
the menu name should be TSPLINK.)
7. Select the RESET to initialize the TSP-Link.
5. Turn on the computer and start Test Script Builder (TSB).
Once the program has started, open a session by connecting
5-8
to the master instrument. For details on how to use TSB, see
the Series 2600 Reference Manual.
You can simply copy and paste the code from Appendix A in
this guide into the TSB script editing window (Program 14),
manually enter the code from the appendix, or import the
TSP file ‘BJT_Comm_Emit_Vsb.tsp’ after downloading it to
your PC.
If your computer is currently connected to the Internet, you
can click on this link to begin downloading: http://www.
keithley.com/data?asset=50928.
6. Install a BJT with substrate connections in appropriate transistor socket of the test fixture. The test is optimized for BJTs
with source requirements similar to a 2N3904.
7. Now, we must send the code to the instrument. The simplest
method is to right-click in the open script window of TSB,
and select ‘Run as TSP file’. This will compile the code and
place it in the volatile run-time memory of the instrument.
To store the program in non-volatile memory, see the “TSP
Programming Fundamentals” section of the Series 2600 Reference Manual.
8. Once the code has been placed in the instrument run-time
memory, we can run it at any time simply by calling the function ‘BJT_Comm_Emit_Vsb()’. This can be done by typing
the text ‘FET _ Comm _ Source _ Vsb()’ after the active
prompt in the Instrument Console line of TSB.
9. In the program ‘BJT_Comm_Emit_Vsb().tsp’, the
function BJT _ Comm _ Emit _ Vsb(istart,
Section 5
Using Substrate Bias
voltage sweep is executed. The base current value is then
incremented and the collector-emitter sweep is re-run.
istop, isteps, vstart, vstop, vsteps,
vsbsource) is created.
11.Once the gate-source sweep has been completed, the data (IB,
VSB, VCE, and IC) will be presented in the Instrument Console
window of TSB.
• istart represents the start value for the base current
sweep
• istop represents the stop value for the base current
sweep
5.4.3 Typical Program 14 Results
• isteps represents the number of steps in the sweep
Figure 5-8 shows a typical plot generated by example Program 14.
• vstart represents the start value for the collectoremitter voltage sweep
5.4.4 Program 14 Description
• vstop represents the stop value for the collector-emitter
voltage sweep
After both instruments are returned to default conditions, Node 1
SMUB, which sweeps IB, is configured as follows:
• vsteps represents the number of steps in the sweep
• Source I
• vsbsource represents the substrate bias voltage
• IV compliance, 1.1V range
If these values are left blank, the function will use the default
values given to the variables, but you can specify each variable value by simply sending a number that is in-range in the
function call. As an example, if you wanted to have the base
current (IB) current sweep start value at 20µA, the base current sweep stop value at 200µA and the number of steps to
be 10, the collector-emitter (VCE) voltage sweep start value
at 1V, the collector-emitter sweep stop value at 12V and the
number of steps to be 80, and the substrate bias to be –2V, you
would send BJT _ Comm _ Em
t _ Vsb(20E-6,
200E-6, 10, 1, 12, 80, -2) to the instrument.
• Local sense
• istart: 10µA
• istop: 50µA
• isteps: 5
Next, Node 1 SMUA, which sweeps VCE and measures IC, is set up
to operate in the following manner:
• Source V
• Local sensing
• 100mA compliance, autorange measure
10.The sources will be enabled, and the substrate bias is applied,
the base current value is applied, and the collector-emitter
• 1 NPLC Line cycle integration
Common-Emitter Characteristics
with Substrate Bias
5.00E–02
I C (Amps)
4.00E–02
3.00E–02
I B = 50µA
I B = 40µA
2.00E–02
I B = 30µA
I B = 20µA
1.00E–02
I B = 10µA
0.00E+00
0
1
2
3
4
5
6
7
8
9
10
VBE (Volts)
Figure 5-8. Program 14 typical results: Common-emitter characteristics with substrate bias
5-9
Section 5
Using Substrate Bias
• vstart: 0V
• vstop: 10V
• vsteps: 100
Finally, Node 2 SMUA, which provides substrate bias, is
programmed:
•
•
•
•
Source V
Local sensing
100mA compliance, autorange measure
vsbsource: 1V
After the instruments have been set up, the outputs are zeroed and
enabled. The substrate bias (VSB) and first base current (IB) values
5-10
are applied. Then, the collector-emitter voltage sweep begins. At
each point in the sweep, the collector current is measured. The
program enters the main program loop to perform five IC vs. VCE
sweeps, one for each of five IB values.
Upon completion of the base current sweep, all outputs are
­zeroed and disabled. The data is written to the Instrument Console of TSB.
5.4.5 Modifying Program 14
For different sweeps, the base current start, stop, step, and
the collector-emitter voltage start, stop, and step values can be
changed as required. For different sweep lengths, loop counter
values must be adjusted accordingly.
Section 6
High Power Tests
6.1 Introduction
accuracy voltage measurements are required. See paragraph 1.2.2
for more information on remote sensing.
Many devices, such as LED arrays and power FETs, require large
current or voltage values for operation or characterization, which
can create issues when testing. While System SourceMeter instruments are extremely flexible, they do have power limitations. For
example, a single SMU channel of a Model 2602 can deliver up to
40W of power. That translates to sourcing 1A at 40V or 40V at 1A.
What do we do if our device requires 2A at 40V?
Luckily, the answer is straightforward if we take certain
precau­tions.
The following examples illustrate how to configure a dual-channel
instrument, such as a Model 2602, 2612, or 2636, to deliver higher
current or voltage values.
6.1.2Example Program 15: High Current
Source and Voltage Measure
Program 15 demonstrates how to deliver higher current sourcing
values using a dual-channel System SourceMeter instrument.
Follow these steps to use this program.
1. With the power off, connect the dual-channel Instrument to
the computer’s IEEE-488 interface.
2. Connect the test fixture to both units using appropriate ­cables.
3. Turn on the instrument and allow the unit to warm up for two
hours for rated accuracy.
6.1.1 Program 15 Test Configuration
4. Turn on the computer and start Test Script Builder (TSB).
Once the program has started, open a session by connecting
to the instrument. For details on how to use TSB, see the
­Series 2600 Reference Manual.
Figure 6-1 shows the test configuration for Program 15. SMUA
and SMUB outputs are wired in parallel: SMUA Output HI to
SMUB Output HI and SMUA Output LO to SMUB output LO. This
effectively doubles the maximum current output and can deliver
a total of 2A at 40V.
5. You can simply copy and paste the code from Appendix A in
this guide into the TSB script editing window (Program 15),
manually enter the code from the appendix, or import the TSP
file ‘KI2602Example_High_Current.tsp’ after downloading it
to your PC.
In this example, local sense is being used to measure voltage, but
you can use remote sensing from one of the SMU channels if high
If your computer is currently connected to the Internet, you
can click on this link to begin downloading: http://www.
keithley.com/data?asset=50965.
IT = I1 + I2 + I3 + I4
I1
2602A
+
2612A
or
2636A
Ch. A –
#1
I2
+
– Ch. B
I3
2602A
+
2612A
or
2636A
Ch. A –
#2
I4
+
DUT
– Ch. B
Figure 6-1. High current (SMUs in parallel)
6-1
Section 6
High Power Tests
6. Install a device (Power FET, LED array, etc.) in the appropriate
transistor socket of the test fixture.
7. Now, we must send the code to the instrument. The simplest
method is to right-click in the open script window of TSB,
and select ‘Run as TSP file’. This will compile the code and
place it in the volatile run-time memory of the instrument.
To store the program in non-volatile memory, see the “TSP
Programming Fundamentals” section of the Series 2600 Reference Manual.
8. Once the code has been placed in the instrument run-time
memory, we can run it at any time simply by calling the function ‘RunHighCurrent(sourcei,points)’, where
sourcei is the desired current value and points is the
number of voltage measurements.
9. In the program ‘KI2602Example_High_Current.tsp’, the function RunHighCurrent(sourcei,points) is created.
• sourcei represents the current value delivered to the
DUT. Note that the programmed current value for each
SMU is half the isource value.
After the instrument is set up, the outputs are zeroed and enabled.
Each SMU performs a DC current source and SMUA begins to
measure the voltage. When the data collection has reached the
desired number of points, the outputs are disabled and the voltage
data is printed to the Instrument Console of TSB.
6.2 Instrument Connections
Warning
If either SMU reaches a compliance state, the instrument, device, or both could be damaged. To avoid
this, set the compliance value to the maximum
for your instrument and avoid open or other high
resistance states for the SMUs when in Current
Source mode.
6.2.1 Program 16 Test Configuration
• points represents the number of voltage measurements
acquired
Figure 6-2 shows the test configuration for Program 16: SMUA
and SMUB outputs are wired in series, SMUA Lo to SMUB Hi,
SMUA Hi to DUT, SMUB Lo to DUT. This effectively doubles the
maximum voltage output and can deliver a total of 80V at 1A using
a Model 2602 System SourceMeter instrument.
If you wanted to source 2A total to the DUT and collect 100
voltage measurements, you would send
­­
RunHighCurrent(2,
100) to the instrument.
6.2.2Example Program 16: High Voltage
Source and Current Measure
10.The sources will be enabled, and the current source and
voltage measurements will be executed.
11.Once the measurements have been completed, the data will
be presented in the Instrument Console window of TSB.
6.1.3 Program 15 Description
Program 16 demonstrates how to deliver higher voltage sourcing
values using a dual-channel System SourceMeter instrument.
Follow these steps to use this program.
1. With the power off, connect the dual-channel Instrument to
the computer’s IEEE-488 interface.
After the SMUs are returned to default conditions, SMUA is configured as follows:
• Source I
• 40V compliance, autorange
Output
LO
Output
HI
Output
HI
Output
LO
• Local sense
• 1 NPLC integration rate
• sourcei: Desired DUT current
• points: Number of points to measure
SMUB
SMUA
Series 2600
System SourceMeter
Next, SMUB is set up to operate in the following manner:
• Source I
• Local sensing
• 40V, autorange
• sourcei: Desired DUT current
6-2
DUT
Figure 6-2. High voltage (SMUs in series)
Section 6
High Power Tests
2. Connect the test fixture to both units using appropriate
­cables.
• points represents the number of voltage measurements
acquired
3. Turn on the Instrument and allow the unit to warm up for two
hours for rated accuracy.
If you wanted to source 80V total to the DUT and collect 100
voltage measurements, you would send
­ unHighVoltage(80, 100) to the instrument.
R
4. Turn on the computer and start Test Script Builder (TSB). Once
the program has started, open a session by connecting to the
instrument. For details on how to use TSB, see the ­Series 2600
Reference Manual.
5. You can simply copy and paste the code from Appendix A in
this guide into the TSB script editing window (Program 16),
manually enter the code from the appendix, or import the TSP
file ‘KI2602Example_High_Voltage.tsp’ after downloading it
to your PC.
If your computer is currently connected to the Internet, you
can click on this link to begin downloading: http://www.
keithley.com/data?asset=50966.
6. Install a device (Power FET, LED array, etc.) in the appropriate
transistor socket of the test fixture.
7. Now, we must send the code to the instrument. The simplest
method is to right-click in the open script window of TSB,
and select ‘Run as TSP file’. This will compile the code and
place it in the volatile run-time memory of the instrument.
To store the program in non-volatile memory, see the “TSP
Programming Fundamentals” section of the Series 2600 Reference Manual.
8. Once the code has been placed in the instrument run-time
memory, we can run it at any time simply by calling the function ‘RunHighVoltage(sourcev, points)’, where
sourcei is the desired voltage value and points is the
number of voltage measurements.
9. In the program ‘KI2602Example_High_Voltage.tsp’, the function RunHighVoltage(sourcev,points) is created.
• sourcev represents the voltage value delivered to the
DUT Note that the actual voltage value programmed for
each SMU is half the sourcev value.
10.The sources will be enabled, and the voltage source and current measurements will be executed.
11.Once the measurements have been completed, the data will
be presented in the Instrument Console window of TSB.
6.2.3 Program 16 Description
After the SMUs are returned to default conditions, SMUA is configured as follows:
• Source V
• 1A compliance, autorange
• 1 NPLC integration rate
• sourcev: DUT voltage
• points: Number of points to measure
Next, SMUB is set up to operate in the following manner:
• Source I
• 1A, autorange
• sourcev: DUT voltage
After the instrument is set up, the outputs are zeroed and enabled.
Each SMU performs a DC voltage source and SMUA begins to
measure the current. When the data collection has reached the
desired number of points, the outputs are disabled and the current data is printed to the Instrument Console of TSB.
Warning:
If either SMU reaches a compliance state, the instrument, device, or both could be damaged. To avoid
this, set the compliance value to the maximum for
your instrument and avoid shorting the SMUs when
in Voltage Source mode.
6-3
Section 6
High Power Tests
6-4
Appendix A
Scripts
Section 2. Two-Terminal Devices
Program 1. Voltage Coefficient of Resistors
--[[
Volt_Co():
This program performs a voltage coefficient measurement on a 10GΩ part.
Required equipment:
(1) Single-channel Keithley Series 2600 System SourceMeter® instrument
(1) 10GΩ resistor
Running this script creates functions that can be used to measure the voltage coefficient
of resistances.
The functions created are:
1. Volt_Co(v1src, v2src) --Default values v1src = 100V, v2src = 200V
2. Check_Comp()
3. Calc_Val(v1src, v2src, i1meas, i2meas)
4. Print_Data(voltco,res1,res2)
See detailed information listed in individual functions.
To run:
1) From Test Script Builder
- Right-click in the program window, select “Run as TSP”
- At the TSP> prompt in the Instrument Control Panel, type Volt_Co()
3) From an external program
- Send the entire program text as a string using standard GPIB Write calls.
Rev1: JAC 5.9.2007
]]--
function Volt_Co(v1src, v2src) --Configure instrument to supply two user-defined
--voltages and measure current.
--Instrument variables.
A-1
Appendix A
Scripts
local l_srcdelay = 0 --Source delay before measurement
local l_icmpl = 1E-3 --Source compliance
local l_nplc = 1 --Measurement Integration Rate
--Define measured and calculated variables
local l_i1meas = 0 --Initialize first current measurement
local l_res1 = 0 --Initialize first resistance measurement
local l_comp_val = false --Initialize compliance variable
local l_v1src = v1src --First voltage source value
local l_v2src = v2src --Second voltage source value
local l_i2meas = 0 --Initialize second current measurement
local l_res2 = 0 --Initialize second resistance measurement
local l_voltco = 0 --Initialize voltage coefficient calculation
--Default values and level check
if (l_v1src == nil) then --Use default value
l_v1src = 100
end --if
if (l_v1src > 100) then --Coerce source value within range
l_v1src = 100
print(“Maximum voltage value is 202V!!”)
end --if
if (l_v2src == nil) then --Use default value
l_v2src = 200
end --if
if (l_v2src > 200) then --Coerce source value within range
l_v2src = 200
print(“Maximum voltage value is 202V!!”)
end --if
--Configure source and measure settings
smua.reset() --Reset SMU
errorqueue.clear() --Clear the error queue
smua.source.func = smua.OUTPUT_DCVOLTS --Output Voltage
smua.source.levelv = 0 --Source 0 before enabling output
smua.measure.nplc = l_nplc --Set integration rate
smua.source.autorangev = smua.AUTORANGE_ON --Enable source autorange
smua.source.limiti = l_icmpl
smua.measure.autorangei = smua.AUTORANGE_ON --Enable measurement autorange
A-2
Appendix A
Scripts
smua.source.output = smua.OUTPUT_ON --Enable output
smua.source.levelv = l_v1src --Source programmed value
l_comp_val = Check_Comp() --check compliance
if l_comp_val == true then
smua.source.output = smua.OUTPUT_OFF --Disable output
smua.source.levelv = 0 --Return source to 0
else
delay(l_srcdelay) --wait before making measurement
l_i1meas = smua.measure.i() --measure current
smua.source.levelv = l_v2src --Source programmed value
delay(l_srcdelay) --wait before making measurement
l_i2meas = smua.measure.i() --Measure current
smua.source.output = smua.OUTPUT_OFF --Disable output
l_voltco, l_res1, l_res2 = Calc_Val(l_v1src, l_v2src, l_i1meas,l_i2meas)
--calculate
Print_Data(l_voltco, l_res1, l_res2) --print
end --if
end --function Volt_Co()
function Check_Comp() --Function checks state of compliance, if true, prints warning and
returns
--to run_test()
local l_comp_val = false --Initialize local variable
l_comp_val = smua.source.compliance --Check compliance
if l_comp_val == true then
print(“”)
print(“SMU Source in Compliance!”)
print(“Ensure proper connections, stable device, and settings are correct”)
print(“Rerun Test”)
print(“”)
end --if
return l_comp_val
end --function Check_Comp()
A-3
Appendix A
Scripts
function Calc_Val(v1src, v2src, i1meas, i2meas)
--function calculates resistance and
voltage coefficient
local l_res1 = v1src/i1meas --Return quotient = resistance calculation
local l_res2 = v2src/i2meas --Return quotient = resistance calculation
local l_voltco = 100*(l_res2-l_res1)/(l_res1*(v2src-v1src)) --Return quotient =
voltage coefficient
return l_voltco, l_res1, l_res2 --Return values
end --function Calc_Val()
function Print_Data(voltco,res1,res2)
local l_voltco = voltco
local l_res1 = res1
local l_res2 = res2
print(“”)
print(“**** Data ****”)
print(“”)
print(“Voltage Coefficient: “, voltco, “%/V”) --Print Voltage Coefficient
print(“”)
print(“Resistance R1: “, res1, “Ohms”) --Print resistance value
print(“Resistance R2: “, res2, “Ohms”) --Print resistance value
end --function Print_Data()
--Volt_Co() --Call Volt_Co()
A-4
Appendix A
Scripts
Program 2. Capacitor Leakage Test
--[[
Cap_Leak():
This program performs capacitor leakage measurement.
Required equipment:
(1) Single-channel Keithley Series 2600 System SourceMeter instrument
(1) 1µF aluminum electrolytic capacitor
Running this script creates functions that can be used to test capacitors.
The functions created are:
1. Cap_Leak(vsrc,soak) --Default value vsrc = 40V
2. Check_Comp()
3. Calc_Val(vsrc, leaki)
4. Print_Data(leaki, leakres)
See detailed information listed in individual functions.
To run:
1) From Test Script Builder
- At the TSP> prompt in the Instrument Control Panel, type Cap_Leak()
2) From an external program
- Send the entire program text as a string using standard GPIB Write calls.
Rev1: JAC 5.22.2007
]]--
function Cap_Leak(vsrc, soak) --Configure instrument to source user-defined voltage
--and measure current.
--Instrument variables.
local l_soak = soak --Source delay before measurement (Recommended 7RC)
local l_icmpl = 1E-2 --Source compliance
local l_nplc = 1 --Measurement Integration Rate
local l_vsrc = vsrc--Voltage source value
--Define measured and calculated variables
local l_leaki = 0 --Initialize leakage current measurement
local l_leakres = 0 --Initialize leakage resistance measurement
local l_comp_val = false --Initialize compliance variable
--Default setting and level check
A-5
Appendix A
Scripts
if (l_vsrc == nil) then --Use default value
l_vsrc = 40
end --if
if (l_vsrc > 100) then --Coerce source value within range
l_vsrc = 100
print(“Maximum voltage value is 100V!!”)
end --if
if (l_soak == nil) then --Use default value
l_soak = 10
end --if
--Configure source and measure settings
smua.reset() --Reset SMU
errorqueue.clear() --Clear the error queue
smua.source.func = smua.OUTPUT_DCVOLTS --Output Voltage
smua.source.levelv = 0 --Source 0 before enabling output
smua.measure.nplc = l_nplc --Set integration rate
smua.source.autorangev = smua.AUTORANGE_ON --Enable source autorange
smua.source.limiti = l_icmpl
smua.measure.autorangei = smua.AUTORANGE_ON --Enable measurement autorange
--Begin test
smua.source.output = smua.OUTPUT_ON --Enable output
smua.source.levelv = l_vsrc --Source programmed value
delay(soak) --wait before making measurement
l_comp_val = Check_Comp() --check compliance
if l_comp_val == true then
smua.source.output = smua.OUTPUT_OFF --Disable output
else
l_leaki = smua.measure.i() --measure current
smua.source.output = smua.OUTPUT_OFF --Disable output
l_leakres = Calc_Val(l_vsrc, l_leaki) --calculate
Print_Data(l_leaki, l_leakres) --print
end --if
end --function Cap_Leak()
A-6
Appendix A
Scripts
function Check_Comp() --Function checks state of compliance, if true, prints warning and
returns
--to run_test()
local l_comp_val = false --Initialize local variable
l_comp_val = smua.source.compliance --Check compliance
if l_comp_val == true then
print(“”)
print(“SMU Source in Compliance!”)
print(“Ensure proper connections, stable device, and settings are correct”)
print(“Rerun Test”)
print(“”)
end --if
return l_comp_val
end --function Check_Comp()
function Calc_Val(vsrc, leaki) --function calculates resistance and voltage coefficient
local l_vsrc = vsrc --Pass global source variable to local
local l_leaki = leaki --Pass global current variable to local
local l_leakres = 0 --Initialize leakage resistance local
l_leakres = vsrc/leaki --Return quotient = resistance calculation
return l_leakres
end --function Calc_Val()
function Print_Data(leaki, leakres)
local l_leaki = leaki
local l_leakres = leakres
print(“”)
print(“**** Data ****”)
print(“”)
print(“Leakage Current: “, l_leaki, “A”) --Print Leakage Current
print(“”)
print(“Leakage Resistance: “, l_leakres, “Ohms”) --Print resistance value
end --function Print_Data()
--Cap_Leak() --Call Cap_Leak() function
A-7
Appendix A
Scripts
Program 3. Diode Characterization
Program 3A. Diode Characterization Linear Sweep
--[[
Diode_Fwd_Char(): USES TABLES
This program performs a forward characterization test on a diode and prints data.
Required equipment:
(1) Single-channel Keithley Series 2600 System SourceMeter instrument
(1) Silicon diode or equivalent
Running this script creates functions that can be used to measure the IV characteristics
of diodes.
The functions created are:
1. Diode_Fwd_Char(ilevel, start, stop, steps) --Default values ilevel = 0s,
start = 1ma, stop = 10ma
--steps = 10
2. Print_Data(steps,volt,curr)
See detailed information listed in individual functions.
To run:
1) From Test Script Builder
- Right-click in the program window, select “Run as TSP”
- At the TSP> prompt in the Instrument Control Panel, type Diode_Fwd_Char()
2) From an external program
- Send the entire program text as a string using standard GPIB Write calls.
Rev1: JAC 5.22.2007
]]--
------------------ Keithley TSP Function -----------------function Diode_Fwd_Char(ilevel, start, stop, steps) --Configure instrument to source a bias
current
--and perform a current sweep from start to stop in a user-defined number of steps. Returns
measured
--voltage and current values.
A-8
--Global variables
Appendix A
Scripts
local l_irange = 100E-2 --Current source range
local l_ilevel = ilevel --Initial source value
local l_vcmpl = 6 --Source compliance
--Shared local variables
local l_nplc = 1 --Integration rate of measurement
--Local sweep variables
local l_start = start --Sweep start current
local l_stop = stop --Sweep stop current
local l_steps = steps --Number of steps in sweep
local l_delay = 0.001 --Source delay
--Default values and level check
if (l_ilevel == nil) then --Use default value
l_ilevel = 0
end --if
if (l_ilevel > 0.1) then --Coerce value
l_ilevel = 0.1
end --if
if (l_start == nil) then --Use default value
l_start = 1E-4
end --if
if (l_start > 1) then --Coerce value
l_start = 1
end --if
if (l_stop == nil) then --Use default value
l_stop = 1E-2
end --if
if (l_stop > 1) then --Coerce value
l_stop = 1
end --if
if (l_steps == nil) then --Use default value
l_steps = 100
end --if
if (l_steps > 1E3) then --Coerce value
l_steps = 1E3
end --if
local l_step = (l_stop - l_start)/ (l_steps - 1) --Current step size
local l_source_val = l_start --Source value during sweep
local l_i = 1 --Iteration variable
A-9
Appendix A
Scripts
--Data tables
local l_curr = {} --Create data table for sourced current
local l_volt = {} --Create data table for measured voltage
smua.reset() --Reset SMU
errorqueue.clear() --Clear the error queue
--Configure SMUA source and measure settings
smua.source.func = smua.OUTPUT_DCAMPS
smua.source.autorangei = smua.AUTORANGE_ON --Enable source autorange
smua.source.leveli = l_ilevel --Source
smua.source.limitv = l_vcmpl
smua.measure.autorangev = smua.AUTORANGE_ON --Enable measure autorange
smua.measure.nplc = l_nplc --Measurement integration rate
smua.source.output = smua.OUTPUT_ON --Enable Output
--Execute sweep
for l_i = 1, l_steps do
--smua.source.leveli = l_source_val
delay(l_delay) --Wait before measurement
l_volt[l_i] = smua.measure.v() --Measure voltage
l_curr[l_i] = smua.measure.i() --Measure current
l_source_val = l_source_val + l_step --Calculate new source value
smua.source.leveli = l_source_val --Increment source
end--for
smua.source.output = smua.OUTPUT_OFF --Disable output
smua.source.leveli = l_ilevel --Return source to bias level
Print_Data(l_steps, l_volt, l_curr)
end--function Diode_Fwd_Chr()
function Print_Data(steps,volt,curr)
--Print Data to output queue
--Local Variables
local l_steps = steps
local l_volt = volt
local l_curr = curr
print(“Voltage Data (V):”)
for l_i = 1, l_steps do
print(l_volt[l_i])
end
print(“”)
A-10
Appendix A
Scripts
print(“Source Current Data (A):”)
for l_i = 1, l_steps do
print(l_curr[l_i])
end
end --function Print_Data()
--Diode_Fwd_Chr()
Program 3B. Diode Characterization Log Sweep
--[[
Diode_Fwd_Char_Log(): USES TABLES
This program performs a log sweep forward characterization test on a diode and prints
data.
Required equipment:
(1) Single-channel Keithley Series 2600 System SourceMeter instrument
(1) Silicon diode or equivalent
Running this script creates functions that can be used to measure the IV characteristics
of diodes.
The functions created are:
1. Diode_Fwd_Char_Log(ilevel, start, stop, points) --Default values ilevel =
0s,
--start = 1ua, stop = 10ma
--points = 10
2. Print_Data(steps,volt,curr)
See detailed information listed in individual functions
To run:
1) From Test Script Builder
- Right-click in the program window, select “Run as TSP”
- At the TSP> prompt in the Instrument Control Panel, type Diode_Fwd_Char_Log()
2) From an external program
- Send the entire program text as a string using standard GPIB Write calls.
Rev1: JAC 10.12.2007
]]--
A-11
Appendix A
Scripts
------------------ Keithley TSP Function -----------------function Diode_Fwd_Char_Log(ilevel, start, stop, points) --CConfigure instrument to source
a bias
--current, and perform a logarithmic current sweep from start to stop in a user-defined
number of points per decade.
--Returns measured voltage and current values.
--Global variables
local l_irange = 100E-2 --Current source range
local l_ilevel = ilevel --Initial source value
local l_vcmpl = 6 --Source compliance
--Shared local variables
local l_nplc = 1 --Integration rate of measurement
--Local sweep variables
local l_start = start --Sweep start current
local l_stop = stop --Sweep stop current
local l_points = points --Number of steps in sweep
local l_delay = 0.01 --Source delay
--Default values and level check
if (l_ilevel == nil) then --Use default value
l_ilevel = 0
end --if
if (l_ilevel > 0.1) then --Coerce value
l_ilevel = 0.1
end --if
if (l_start == nil) then --Use default value
l_start = 1E-6
end --if
if (l_start > 1) then --Coerce value
l_start = 1
end --if
if (l_stop == nil) then --Use default value
l_stop = 1E-2
end --if
if (l_stop > 1) then --Coerce value
l_stop = 1
end --if
if (l_points == nil) then --Use default value
l_points = 10
A-12
Appendix A
Scripts
end --if
if (l_points > 1E3) then --Coerce value
l_points = 1E3
end --if
local l_step = (math.log10(l_stop) - math.log10(l_start))/(l_points - 1)
--Current step size
local l_source_val = math.log10(l_start) --Source value during sweep
local l_i = 1 --Iteration variable
--Data tables
local l_curr = {} --Create data table for sourced current
local l_volt = {} --Create data table for measured voltage
smua.reset() --Reset SMU
errorqueue.clear() --Clear the error queue
--Configure SMUA source and measure settings
smua.source.func = smua.OUTPUT_DCAMPS
smua.source.autorangei = smua.AUTORANGE_ON --Enable source autorange
smua.source.leveli = l_ilevel --Source bias
smua.source.limitv = l_vcmpl
smua.measure.autorangev = smua.AUTORANGE_ON --Enable measure autorange
smua.measure.nplc = l_nplc --Measurement integration rate
smua.source.output = smua.OUTPUT_ON --Enable Output
--Execute sweep
for l_i = 1, l_points do
smua.source.leveli = math.pow(10, l_source_val) -- Program source to sweep
level.
delay(l_delay) --Wait before measurement
l_volt[l_i] = smua.measure.v() --Measure voltage
l_curr[l_i] = smua.measure.i() --Measure current
l_source_val = l_source_val + l_step --Increment source value
end--for
smua.source.output = smua.OUTPUT_OFF --Disable output
smua.source.leveli = l_ilevel --Return source to bias level
Print_Data(l_points, l_volt, l_curr)
end--function Diode_Fwd_Chr()
function Print_Data(points,volt,curr)
A-13
Appendix A
Scripts
--Print Data to output queue
--Local Variables
local l_points = points
local l_volt = volt
local l_curr = curr
print(“Voltage Data (V):”)
for l_i = 1, l_points do
print(l_volt[l_i])
end
print(“”)
print(“Source Current Data (A):”)
for l_i = 1, l_points do
print(l_curr[l_i])
end
end --function Print_Data()
--Diode_Fwd_Chr_Log()
Program 3C. Diode Characterization Pulsed Sweep
--[[
Diode_Fwd_Char_Pulse(): USES TABLES
This program performs a forward characterization test on a diode using a pulsed source and
prints data. The default is a 50% duty cycle (i.e., ton = toff)
Required equipment:
(1) Single-channel Keithley Series 2600 System SourceMeter instrument
(1) Silicon diode or equivalent
Running this script creates functions that can be used to measure the IV characteristics
of diodes.
The functions created are:
1. Diode_Fwd_Char_Pulse(ilevel, start, stop, ton, toff, steps) --Default values ilevel =
0s, start =
--1ma, stop = 10ma, ton =
10ms,
--toff = 10ms, steps = 10
2. Print_Data(steps,volt,curr)
See detailed information listed in individual functions
A-14
Appendix A
Scripts
To run:
1) From Test Script Builder
- Right-click in the program window, select “Run as TSP”
- At the TSP> prompt in the Instrument Control Panel, type Diode_Fwd_Char()
2) From an external program
- Send the entire program text as a string using standard GPIB Write calls.
Rev1: JAC 5.22.2007
]]--
------------------ Keithley TSP Function -----------------function Diode_Fwd_Char_Pulse(ilevel, start, stop, ton, toff, steps) --Configure instrument
to source a
--bias current,and perform a pulsed current sweep from start to stop in a user-defined
number of steps.
--Each pulse is on ton (s) and off toff (s) and returns to the bias level during the toff
time.
--Returns measured voltage and current values.
--Global variables
local l_irange = 100E-2 --Current source range
local l_ilevel = ilevel --Initial source value
local l_vcmpl = 6 --Source compliance
--Shared local variables
local l_nplc = 0.1 --Integration rate of measurement
--Local sweep variables
local l_start = start --Sweep start current
local l_stop = stop --Sweep stop current
local l_steps = steps --Number of steps in sweep
local l_delay = 0.001 --Source delay
local l_ton = ton --Pulse on duration
local l_toff = toff --Pulse off duration
local l_tonwm --Adjusted Pulse on duration to accomodate Measurement Duration
--Default values and level check
if (l_ilevel == nil) then --Use default value
l_ilevel = 0
end --if
if (l_ilevel > 1E-1) then --Coerce value
l_ilevel = 1E-1
end --if
A-15
Appendix A
Scripts
if (l_start == nil) then --Use default value
l_start = 1E-3
end --if
if (l_start > 0.1) then --Coerce value
l_start = 0.1
end --if
if (l_stop == nil) then --Use default value
l_stop = 1E-2
end --if
if (l_stop > 0.1) then --Coerce value
l_stop = 0.1
end --if
if (l_ton == nil) then --Use default value
l_ton = 10E-3
end --if
if (l_ton > 1E-1) then --Coerce value
l_ton = 1E-1
end --if
if (l_toff == nil) then --Use default value
l_toff = 10E-3
end --if
if (l_toff > 1E-1) then --Coerce value
l_toff = 1E-1
end --if
if (l_steps == nil) then --Use default value
l_steps = 100
end --if
if (l_steps > 1E3) then --Coerce value
l_steps = 1E3
end --if
local l_step = (l_stop - l_start)/ (l_steps - 1) --Current step size
local l_source_val = l_start --Source value during sweep
local l_i = 1 --Iteration variable
--Data tables
local l_curr = {} --Create data table for sourced current
local l_volt = {} --Create data table for measured voltage
A-16
Appendix A
Scripts
l_tonwm = l_ton - (2*smua.measure.nplc/localnode.linefreq) - 250E-6 --Adjust pulse
duration by
--accounting for measurement time
smua.reset() --Reset SMU
errorqueue.clear() --Clear the error queue
--Configure SMUA source and measure settings
smua.source.func = smua.OUTPUT_DCAMPS
smua.source.autorangei = smua.AUTORANGE_ON --Enable source autorange
smua.source.leveli = l_ilevel --Source
smua.source.limitv = l_vcmpl
smua.measure.autorangev = smua.AUTORANGE_ON --Enable measure autorange
smua.measure.nplc = l_nplc --Measurement integration rate
smua.source.output = smua.OUTPUT_ON --Enable Output
--Execute sweep
for l_i = 1, l_steps do
smua.source.leveli = l_source_val
delay(l_tonwm)
-- Wait pulse time - measurement & overhead time.
l_volt[l_i] = smua.measure.v() --Measure voltage
l_curr[l_i] = smua.measure.i() --Measure current
smua.source.leveli = l_ilevel -- Return source to bias level.
delay(l_toff)
-- Wait pulse off time.
l_source_val = l_source_val + l_step --Calculate new source value
smua.source.leveli = l_source_val --Increment source --]]
end--for
smua.source.output = smua.OUTPUT_OFF --Disable output
smua.source.leveli = l_ilevel --Return source to bias level
Print_Data(l_steps, l_volt, l_curr)
end--function Diode_Fwd_Chr()
function Print_Data(steps,volt,curr)
--Print Data to output queue
--Local Variables
local l_steps = steps
local l_volt = volt
local l_curr = curr
print(“Voltage Data (V):”)
for l_i = 1, l_steps do
print(l_volt[l_i])
end
A-17
Appendix A
Scripts
print(“”)
print(“Source Current Data (A):”)
for l_i = 1, l_steps do
print(l_curr[l_i])
end
end --function Print_Data()
--Diode_Fwd_Chr_Pulse()
A-18
Appendix A
Scripts
Section 3. Bipolar Transistor Tests
Program 4. Common-Emitter Characteristics
--[[
BJT_Comm_Emit(): USES TABLES
This program applies a bias to the base of a BJT (Ib) and sweeps voltage on the collector/
emitter (VCE). The VCE, IB, and IC are then printed.
Required equipment:
(1) Dual-channel Series 2600 System SourceMeter instrument
(1) 2N5089 NPN Transistor
Running this script creates functions that can be used to measure the common emitter
characteristics of transistors. The default values are for an NPN transistor type 2N5089.
The functions created are:
1. BJT_Comm_Emit(istart, istop, isteps, vstart, vstop, vsteps)
--Default values istart = 10uA, istop = 50uA, isteps = 5, vstart = 0V,
vstop = 10V, vsteps = 100
2. Print_Data(isteps,vsteps, ce_volt,ce_curr, base_curr)
See detailed information listed in individual functions.
1) From Test Script Builder
- At the TSP> prompt in the Instrument Control Panel, type BJT_Comm_Emit()
2) From an external program
- Send the entire program text as a string using standard GPIB Write calls.
Rev1: JAC 5.22.2007
]]--
------------------ Keithley TSP Function -----------------function BJT_Comm_Emit(istart,
source a bias
--current on the base and SMUA
start to stop in a
--user-defined number of steps.
--SMUB then increments to next
--Returns measured voltage and
istop, isteps, vstart, vstop, vsteps) --Configure SMUB to
performs a voltage sweep on the Collector-Emitter from
bias value and continues to stop value.
current values.
--Global variables
local l_irange = 100E-6 --Base current source range
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local l_vcmpl = 1 --Base source compliance
local l_vrange = 40 --Collector-emitter voltage source range
local l_icmpl = 100E-3 --Collector-emitter source compliance
--Shared local variables
local l_nplc = 1 --Integration rate of measurement
--Local sweep variables
local l_istart = istart --Base sweep start current
local l_istop = istop --Base sweep stop current
local l_isteps = isteps --Number of steps in sweep
local l_vstart = vstart --Collector-emitter sweep start voltage
local l_vstop = vstop --Collector-emitter sweep stop voltage
local l_vsteps = vsteps --Number of steps in sweep
--Default values and level check
if (l_istart == nil) then --Use default value
l_istart = 10E-6
end --if
if (l_istart > 100E-6) then --Coerce value
l_istart = 100E-6
end --if
if (l_istop == nil) then --Use default value
l_istop = 50E-6
end --if
if (l_istop > 500E-6) then --Coerce value
l_istop = 500E-6
end --if
if (l_isteps == nil) then --Use default value
l_isteps = 5
end --if
if (l_isteps > 100) then --Coerce value
l_isteps = 100
end --if
local l_istep = (l_istop - l_istart)/ (l_isteps - 1) --Current step size
local l_isource_val = l_istart --Source value during sweep
local l_i = 1 --Iteration variable
if (l_vstart == nil) then --Use default value
l_vstart = 0
end --if
A-20
Appendix A
Scripts
if (l_vstart > 100E-3) then --Coerce value
l_vstart = 100E-3
end --if
if (l_vstop == nil) then --Use default value
l_vstop = 10
end --if
if (l_vstop > 40) then --Coerce value
l_vstop = 40
end --if
if (l_vsteps == nil) then --Use default value
l_vsteps = 100
end --if
if (l_vsteps > 2E+2) then --Coerce value
l_vsteps = 2E+2
end --if
local l_vstep = (l_vstop - l_vstart)/ (l_vsteps - 1) --Voltage step size
local l_vsource_val = l_vstart --Source value during sweep
local l_v = 1 --Iteration variable
--Data tables
local l_base_curr = {} --Create data table for sourced current
local l_ce_volt = {} --Create data table for collector-emitter measured voltage
local l_ce_curr = {} --Create data table for collector-emitter measured current
smua.reset() --Reset SMU
smub.reset() --Reset SMU
errorqueue.clear() --Clear the error queue
--Configure Collector/Emitter (SMUA) source and measure settings
smua.source.func = smua.OUTPUT_DCVOLTS
smua.source.autorangev = smua.AUTORANGE_ON --Enable source autorange
smua.source.levelv = 0
smua.source.limiti = l_icmpl
smua.measure.autorangei = smua.AUTORANGE_ON --Enable measure autorange
smua.measure.autozero = smua.AUTOZERO_AUTO
smua.measure.nplc = l_nplc --Measurement integration rate
smua.source.output = smua.OUTPUT_ON --Enable Output
--Configure Base (SMUB) source and measure settings
smub.source.func = smub.OUTPUT_DCAMPS
smub.source.autorangei = smub.AUTORANGE_ON --Enable source autorange
smub.source.leveli = 0
A-21
Appendix A
Scripts
smub.source.limitv = l_vcmpl
smub.measure.autorangev = smub.AUTORANGE_ON --Enable measure autorange
smub.measure.autozero = smub.AUTOZERO_AUTO
smub.measure.nplc = l_nplc --Measurement integration rate
smub.source.output = smub.OUTPUT_ON --Enable Output
--Execute sweep
for l_i = 1, l_isteps do
smub.source.leveli = l_isource_val
l_ce_volt[l_i] = {} --Create new row in table
l_ce_curr[l_i] = {} --Create new row in table
l_base_curr[l_i] = smub.measure.i() --Measure base current
for l_v = 1,l_vsteps do
if (l_v == 1) then --Intialize start source value
l_vsource_val = l_vstart
end --if
delay(0.001) --Delay
l_ce_volt[l_i][l_v] = smua.measure.v() --Measure voltage
l_ce_curr[l_i][l_v] = smua.measure.i() --Measure current
l_vsource_val = l_vsource_val + l_vstep --Calculate new source value
if (l_v == l_vsteps) then --Reinitialize voltage value after last
iteration
l_vsource_val = l_vstart
end --if
smua.source.levelv = l_vsource_val --Increment source
end --for
l_isource_val = l_isource_val + l_istep --Calculate new source value
end--for
A-22
smua.source.output = smua.OUTPUT_OFF --Disable output
smub.source.output = smub.OUTPUT_OFF --Disable output
smua.source.levelv = 0 --Return source to bias level
smub.source.leveli = 0 --Return source to bias level
Appendix A
Scripts
Print_Data(l_isteps,l_vsteps, l_ce_volt, l_ce_curr, l_base_curr)
end--function BJT_Comm_Emit()
function Print_Data(isteps,vsteps, ce_volt,ce_curr, base_curr)
--Print Data to output queue
--Local Variables
local l_isteps = isteps
local l_vsteps = vsteps
local l_i = 1 --Iteration variable
local l_v = 1 --Iteration variable
local l_ce_volt = ce_volt
local l_ce_curr = ce_curr
local l_base_curr = base_curr
for l_i = 1, l_isteps do
print(“”)
print(“Base Current Bias”, l_base_curr[l_i])
print(“Emitter Voltage (V)”,”Emitter Current (A)”)
for l_v = 1, l_vsteps do
print(l_ce_volt[l_i][l_v], l_ce_curr[l_i][l_v])
end --for
end --for
end --function Print_Data()
--BJT_Comm_Emit()
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Appendix A
Scripts
Program 5. Gummel Plot
--[[
Gummel(): USES TABLES
This program performs a series of voltage sweeps on the base-emitter (VBE) of a BJT at a
fixed collector-emitter voltage (VCE). The base-emitter (IB) and collector-emitter (IC)
currents are measured and printed.
Required equipment:
(1) Dual-channel Keithley Series 2600 System SourceMeter instrument
(1) 2N5089 NPN Transistor
Running this script creates functions that can be used to create a Gummel plot of
transistors. The default values are for an NPN transistor type 2N5089.
The functions created are:
1. Gummel(vbestart, vbestop, vbesteps, vcebias)
--Default values vbestart = 0V, vbestop = 0.7V, vbesteps = 70, vcebias =
10V
2. Print_Data(vbesteps,vbe, vcebias, ic, ib)
See detailed information listed in individual functions.
To run:
1) From Test Script Builder
- Right-click in the program window, select “Run as TSP”
- At the TSP> prompt in the Instrument Control Panel, type Gummel()
2) From an external program
- Send the entire program text as a string using standard GPIB Write calls.
Rev1: JAC 5.30.2007
]]--
------------------ Keithley TSP Function -----------------function Gummel(vbestart, vbestop, vbesteps, vcebias) --Configure SMUB to perform a voltage
sweep on the
--base (Vbe) from start to stop in a user-defined number of steps while SMUA performs a
fixed voltage bias on the
--collector-emitter. SMUA then increments to next bias value and continues to stop value.
--Returns measured Ib, Ic, and Vbe.
A-24
--Global variables
local l_icmpl = 100E-3 --Source compliance
Appendix A
Scripts
--Shared local variables
local l_nplc = 1 --Integration rate of measurement
--Local sweep variables
local l_vbestart = vbestart --Base sweep start voltage
local l_vbestop = vbestop --Base sweep stop voltage
local l_vbesteps = vbesteps --Number of steps in sweep
local l_vcebias = vcebias --Collector-emitter voltage
--Default values and level check
if (l_vbestart == nil) then --Use default value
l_vbestart = 0
end --if
if (l_vbestart > 100E-6) then --Coerce value
l_vbestart = 100E-6
end --if
if (l_vbestop == nil) then --Use default value
l_vbestop = 700E-3
end --if
if (l_vbestop > 1) then --Coerce value
l_vbestop = 1
end --if
if (l_vbesteps == nil) then --Use default value
l_vbesteps = 70
end --if
if (l_vbesteps > 100) then --Coerce value
l_vbesteps = 100
end --if
local l_vbestep = (l_vbestop - l_vbestart)/ (l_vbesteps - 1) --Vbe step size
local l_vbesource_val = l_vbestart --Source value during sweep
local l_vbe_i = 1 --Iteration variable
if (l_vce_bias == nil) then --Use default value
l_vce_bias = 10
end --if
if (l_vce_bias > 40) then --Coerce value
l_vce_bias = 40
end --if
--Data tables
local l_vbe = {} --Create data table for sourced voltage
A-25
Appendix A
Scripts
local l_ic = {} --Create data table for Ic
local l_ib = {} --Create data table for Ib
smua.reset() --Reset SMU
smub.reset() --Reset SMU
errorqueue.clear() --Clear the error queue
--Configure Collector/Emitter (SMUA) source and measure settings
smua.source.func = smua.OUTPUT_DCVOLTS
smua.source.autorangev = smua.AUTORANGE_ON --Enable source autorange
smua.source.levelv = 0
smua.source.limiti = l_icmpl
smua.measure.autorangei = smua.AUTORANGE_ON --Enable measure autorange
smua.measure.autozero = smua.AUTOZERO_AUTO
smua.measure.nplc = l_nplc --Measurement integration rate
smua.source.output = smua.OUTPUT_ON --Enable Output
--Configure Base (SMUB) source and measure settings
smub.source.func = smub.OUTPUT_DCVOLTS
smub.source.autorangev = smub.AUTORANGE_ON --Enable source autorange
smub.source.levelv = 0
smub.source.limiti = l_icmpl
smub.measure.autorangev = smub.AUTORANGE_ON --Enable measure autorange
smub.measure.autozero = smub.AUTOZERO_AUTO
smub.measure.nplc = l_nplc --Measurement integration rate
smub.source.output = smub.OUTPUT_ON --Enable Output
smua.source.levelv = l_vce_bias
--Execute sweep
for l_vbe_i = 1,l_vbesteps do
if (l_vbe_i == 1) then --Intialize start source value
l_vbesource_val = l_vbestart
end --if
delay(0.01) --Delay
l_vbe[l_vbe_i] = smub.measure.v() --Measure Vbe
l_ib[l_vbe_i] = smub.measure.i() --Measure Ib
l_ic[l_vbe_i] = smua.measure.i() --Measure Ic
l_vbesource_val = l_vbesource_val + l_vbestep --Calculate new source value
A-26
Appendix A
Scripts
if (l_vbe_i == l_vbesteps) then --Reinitialize voltage value after last
iteration
l_vbesource_val = l_vbestart
end --if
smub.source.levelv = l_vbesource_val --Increment source
end --for
smua.source.output = smua.OUTPUT_OFF --Disable output
smub.source.output = smub.OUTPUT_OFF --Disable output
smua.source.levelv = 0 --Return source to bias level
smub.source.levelv = 0 --Return source to bias level
Print_Data(l_vbesteps, l_vbe,l_vce_bias, l_ic, l_ib)
end--function Gummel()
function Print_Data(vbesteps,vbe, vcebias, ic, ib)
--Print Data to output queue
--Local Variables
local l_vbesteps = vbesteps
local l_vbe_i = 1 --Iteration variable
local l_vbe = vbe
local l_vce_bias = vcebias
local l_ic = ic
local l_ib = ib
print(“”)
print(“Vce”, l_vce_bias)
print(“Vbe (V)”,”Ib (A)”,”Ic (A)”)
for l_vbe_i = 1, l_vbesteps do
print(l_vbe[l_vbe_i],l_ic[l_vbe_i], l_ib[l_vbe_i])
end --for
end --function Print_Data()
--Gummel()
A-27
Appendix A
Scripts
Section 6. High Power Tests
Program 6. Current Gain
Program 6A. Current Gain (Search Method)
--[[
DC_Gain_Search():
This program performs a binary search on the base current (IB) of a BJT at a fixed
collector-emitter voltage (VCE). The base-emitter (IB) and collector-emitter (IC) currents
are measured and the IB, IC, and DC gain values are printed.
Required equipment:
(1) Dual-channel Keithley Series 2600 System SourceMeter instrument
(1) 2N5089 NPN transistor
Running this script creates functions that can be used to create a DC gain search of
transistors. The default values are for an NPN transistor type 2N5089.
The functions created are:
1. DC_Gain_Search(vcesource, lowib, highib, targetic)
--Default values vcesource = 5V, lowib = 1e-9A, highib = 100e-7A,
targetic = 100e-6A
2. Check_Comp()
See detailed information listed in individual functions.
To run:
1) From Test Script Builder
- Right-click in the program window, select “Run as TSP”
- At the TSP> prompt in the Instrument Control Panel, type DC_Gain_Search()
2) From an external program
- Send the entire program text as a string using standard GPIB Write calls.
Rev1: JAC 6.11.2007
]]--
------------------ Keithley TSP Function -----------------function DC_Gain_Search(vcesource, lowib, highib, targetic) --Configure SMUB to source a
user-defined
--current on the base (Ib) while SMUA performs a fixed voltage bias on the collectoremitter. SMUB then performs a
A-28
Appendix A
Scripts
--binary search between a Maximum and Minimum Ib value, and the collector current is
measured. If measured value is
--outside the tolerance, search is performed again until the value falls within the
specified range or the iteration
--limit is reached.
--Returns measured Ib, Ic, and the DC Gain/Beta.
local l_k --binary search iteration variable
local l_k_max = 20 --Maximum loop iteration
local l_vce_source = vcesource --VCEsource value
local l_high_ib = highib --Start Ib high limit
local l_low_ib = lowib --Start Ib lo limit
local l_target_ic = targetic --Target Ic for binary search
local l_nplc = 1
local l_ic_meas
local l_ib_source --Base current
local l_beta_meas
--Default values and level check
if (l_vce_source == nil) then --Use default value
l_vce_source = 5
end --if
if (l_low_ib == nil) then --Use default value
l_low_ib = 1e-9
end --if
if (l_high_ib == nil) then --Use default value
l_high_ib = 100E-7
end --if
if (l_target_ic == nil) then --Use default value
l_target_ic = 100e-6
end --if
smua.reset() --Reset SMU
smub.reset() --Reset SMU
errorqueue.clear() --Clear the error queue
smua.measure.nplc = l_nplc --Measurement integration rate
smub.measure.nplc = l_nplc --Measurement integration rate
smua.source.func = smua.OUTPUT_DCVOLTS
smua.source.autorangev = smua.AUTORANGE_ON --Enable source autorange
smua.source.limiti = (100 * l_target_ic) --Set compliance value
smua.measure.autorangev = smua.AUTORANGE_ON --Enable measure autorange
smub.source.func = smub.OUTPUT_DCAMPS
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Appendix A
Scripts
smub.source.autorangei = smub.AUTORANGE_ON --Enable source autorange
smub.source.limiti = l_high_ib
smub.source.limitv = 6
smub.measure.autorangev = smub.AUTORANGE_ON --Enable measure autorange
--Start test
smua.source.levelv = l_vce_source --Set source level
smub.source.leveli = 0 --Set source level
smua.source.output = smua.OUTPUT_ON --Enable output
smub.source.output = smub.OUTPUT_ON --Enable output
delay(0.001) --Delay
l_comp_val = Check_Comp() --check compliance
if l_comp_val == true then --If unit is in compliance, end
smua.source.output
smub.source.output
smua.source.levelv
smub.source.leveli
else
= smua.OUTPUT_OFF --Disable output
= smub.OUTPUT_OFF --Disable output
= 0 --Return source to 0
= 0 --Return source to 0
--Search for the right base current
l_k = 0
repeat --Repeat search until measured Ic is within 5% of target, iteration maximum
reached, or
--compliance.
l_k = l_k + 1 --Increment
l_ib_source = ((l_high_ib-l_low_ib)/2) + l_low_ib --Determine source value
(Binary Search)
smub.source.leveli = l_ib_source --Program new source value
delay(0.0001) --Source delay
l_comp_val = Check_Comp() --check compliance
if l_comp_val == true then --If unit is in compliance, end
smua.source.output = smua.OUTPUT_OFF --Disable output
smub.source.output = smub.OUTPUT_OFF --Disable output
smua.source.levelv = 0 --Return source to 0
smub.source.leveli = 0 --Return source to 0
else
A-30
Appendix A
Scripts
l_ic_meas = smua.measure.i() --Measure Ic
if (l_target_ic < l_ic_meas) then --Compare measurement with
target value
l_high_ib = l_ib_source
else
l_low_ib = l_ib_source
end --end if
end --ifelse
if l_ic_meas == nil then --If no measurement taken, initialize to 0 to avoid arithmetic
--error in until statement below
l_ic_meas = 0
end --if
until ((math.abs(l_ic_meas - l_target_ic) < (0.05*l_target_ic))or(l_k>l_k_max))
or(l_comp_val == true) -
--iteration limit reached
if (l_k > l_k_max) then
print(“Iteration Limit Reached!!”)
end --end if
smua.source.output = smua.OUTPUT_OFF --Disable output
smub.source.output = smub.OUTPUT_OFF --Disable output
l_beta_data = l_ic_meas/l_ib_source --Calculate gain
print(“Ic Data:”, l_ic_meas) --Print Ic data
print(“Ib Data:”, l_ib_source) --Print Ib
print(“Beta Data:”,l_beta_data) --Print gain
end --ifelse
end--function DC_Gain_Search()
function Check_Comp() --Function checks state of compliance, if true, prints warning and
returns
--to run_test()
local l_comp_val = false --Initialize local variable
l_comp_val = smua.source.compliance --Check compliance
if l_comp_val == true then
print(“”)
print(“SMU Source in Compliance!”)
print(“Ensure proper connections, stable device, and settings are correct”)
print(“Rerun Test”)
print(“”)
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Appendix A
Scripts
end --if
return l_comp_val
end --function Check_Comp()
--DC_Gain_Search()
Program 6B. Current Gain (Fast Method)
--[[
DC_Gain_Fast()
This program applies a bias to the collector/emitter of a BJT (Vce) and sweeps current on
the emitter (IE). The gain for each emitter value is then printed.
Required equipment:
(1) Dual-channel Keithley Series 2600 System SourceMeter instrument
(1) 2N5089 NPN Transistor
Running this script creates functions that can be used to measure the gain characteristics
of transistors. The default values are for an NPN transistor type 2N5089.
The functions created are:
1. DC_Gain_Fast(vcesource, istart, istop, isteps)
--Default values vcesource = 10V, istart = 1mA, istop = 10mA, isteps = 10
2. Print_Data(isteps, emitter_curr, base_curr)
See detailed information listed in individual functions.
1) From Test Script Builder
- At the TSP> prompt in the Instrument Control Panel, type DC_Gain_Fast()
2) From an external program
- Send the entire program text as a string using standard GPIB Write calls.
Rev1: JAC 6.11.2007
]]--
------------------ Keithley TSP Function -----------------function DC_Gain_Fast(vcesource, istart, istop, isteps) --Configure SMUB to source a bias
voltage
--on the base and SMUA performs a current sweep on the emitter from start to stop in a
user-defined number of steps.
A-32
Appendix A
Scripts
--Returns gain values.
--Global variables
local l_irange = 100e-6 --Base current source range
local l_vcmpl = 11 --Base source compliance
local l_vrange = 40 --Collector-emitter voltage source range
local l_icmpl = 100e-3 --Collector-emitter source compliance
--Shared local variables
local l_nplc = 1 --Integration rate of measurement
--Local sweep variables
local l_istart = istart --Base sweep start current
local l_istop = istop --Base sweep stop current
local l_isteps = isteps --Number of steps in sweep
local l_vce_source = vcesource --Vce source value
--Default values and level check
if (l_vce_source == nil) then --Use default value
l_vce_source = -10
end --if
if (l_vce_source > 0) then --Coerce value
l_vce_source = -l_vce_source
end --if
if (l_istart == nil) then --Use default value
l_istart = -1e-3
end --if
if (l_istart > 0) then --Coerce value
l_istart = -l_istart
end --if
if (l_istop == nil) then --Use default value
l_istop = -10e-3
end --if
if (l_istop > 0) then --Coerce value
l_istop = -i_stop
end --if
if (l_isteps == nil) then --Use default value
l_isteps = 10
end --if
if (l_isteps > 100) then --Coerce value
l_isteps = 100
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Appendix A
Scripts
end --if
local l_istep = (l_istop - l_istart)/ (l_isteps - 1) --Current step size
local l_isource_val = l_istart --Source value during sweep
local l_i = 1 --Iteration variable
--Data tables
local l_base_curr = {} --Create data table for sourced current
local l_emitter_curr = {} --Create data table for emitter current
smua.reset() --Reset SMU
smub.reset() --Reset SMU
errorqueue.clear() --Clear the error queue
--Configure emitter current (SMUA) source and measure settings
smua.source.func = smua.OUTPUT_DCAMPS
smua.source.autorangei = smua.AUTORANGE_ON --Enable source autorange
smua.source.leveli = 0
smua.source.limitv = l_vcmpl
smua.source.output = smua.OUTPUT_ON --Enable Output
--Configure collector/emitter (SMUB) source and measure settings
smub.source.func = smub.OUTPUT_DCVOLTS
smub.source.autorangei = smub.AUTORANGE_ON --Enable source autorang
smub.source.levelv = 0
smub.source.limiti = l_icmpl
smub.measure.autorangei = smub.AUTORANGE_ON --Enable measure autorange
smub.measure.autozero = smub.AUTOZERO_AUTO
smub.measure.nplc = l_nplc --Measurement integration rate
smub.source.output = smub.OUTPUT_ON --Enable Output
smub.source.levelv = l_vce_source --Program source
--Execute sweep
for l_i = 1, l_isteps do
smua.source.leveli = l_isource_val
delay(0.01)
l_base_curr[l_i] = smub.measure.i() --Measure base current
l_emitter_curr[l_i] = smua.measure.i() --Measure emitter current
l_isource_val = l_isource_val + l_istep --Calculate new source value
end--for
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Appendix A
Scripts
smua.source.output = smua.OUTPUT_OFF --Disable output
smub.source.output = smub.OUTPUT_OFF --Disable output
smua.source.levelv = 0 --Return source to bias level
smub.source.leveli = 0 --Return source to bias level
Print_Data(l_isteps, l_emitter_curr, l_base_curr)
end--function DC_Gain_Fast()
function Print_Data(isteps, emitter_curr, base_curr)
--Print Data to output queue
--Local Variables
local l_isteps = isteps
local l_i = 1 --Iteration variable
local l_emitter_curr = emitter_curr
local l_base_curr = base_curr
local l_gain = {} --Gain variable
print(“”)
print(“Base Current (A)”, “Emitter Current (A)”, “Gain”)
for l_i = 1, l_isteps do
l_gain[l_i] = (math.abs(l_emitter_curr[l_i]) - math.abs(l_base_curr[l_i]))/math.
abs(l_base_curr[l_i]) ----Calculate gain
print(math.abs(l_base_curr[l_i]), math.abs(l_emitter_curr[l_i]), l_
gain[l_i])
end --for
end --function Print_Data()
--DC_Gain_Fast()
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Program 7. AC Current Gain
--[[
AC_Gain():
This program sources two base currents (IB) on a BJT at a fixed collector-emitter voltage
(VCE). The base-emitter (IB) and collector-emitter (IC) currents are measured and the IB,
IC, and AC gain values are printed.
Required equipment:
(1) Dual-channel Keithley Series 2600 System SourceMeter instrument
(1) 2N5089 NPN transistor
Running this script creates functions that can be used to perform a differential gain
measurement on transistors. The default values are for an NPN transistor type 2N5089.
The functions created are:
1. AC_Gain(vcesource, ib1, ib2)
--Default values vcesource = 5V, ib1 = 1e-7A, ib2= 2e-7A
2. Check_Comp()
See detailed information listed in individual functions.
To run:
1) From Test Script Builder
- Right-click in the program window, select “Run as TSP”
- At the TSP> prompt in the Instrument Control Panel, type AC_Gain()
2) From an external program
- Send the entire program text as a string using standard GPIB Write calls.
Rev1: JAC 6.12.2007
]]--
------------------ Keithley TSP Function -----------------function AC_Gain(vcesource, ib1, ib2) --Configure SMUB to source a user-defined current on
the base (Ib)
--while SMUA performs a fixed voltage bias on the collector-emitter and the Ic is measured.
--SMUB then steps to the next base current and the Ic is measured.
--The AC Gain is then calculated.
--Returns measured Ib1, Ib2, Ic1, Ic2 and the AC Gain/Beta.
local l_vce_source = vcesource --VCEsource value
local l_ib1 = ib1 --Ib 1 source value
A-36
Appendix A
Scripts
local l_ib2 = ib2 --Ib 2 source value
local l_nplc = 1
local l_ic_meas1 = 0 --Ic measurement
local l_ic_meas2 = 0 --Ic measurement
local l_beta_meas --Gain calculation variable
--Default values and level check
if (l_vce_source == nil) then --Use default value
l_vce_source = 5
end --if
if (l_ib1 == nil) then --Use default value
l_ib1 = 1.45e-7
end --if
if (l_ib2 == nil) then --Use default value
l_ib2 = 1.6e-7
end --if
smua.reset() --Reset SMU
smub.reset() --Reset SMU
errorqueue.clear() --Clear the error queue
smua.measure.nplc = l_nplc --Measurement integration rate
smub.measure.nplc = l_nplc --Measurement integration rate
smua.source.func = smua.OUTPUT_DCVOLTS
smua.source.autorangev = smua.AUTORANGE_ON --Enable source autorange
smua.measure.autorangev = smua.AUTORANGE_ON --Enable measure autorange
smub.source.func = smub.OUTPUT_DCAMPS
smub.source.autorangei = smub.AUTORANGE_ON --Enable source autorange
smub.source.limitv = 6
smub.measure.autorangev = smub.AUTORANGE_ON --Enable measure autorange
--Start test
smua.source.levelv = l_vce_source --Set source level
smub.source.leveli = 0 --Set source level
smua.source.output = smua.OUTPUT_ON --Enable output
smub.source.output = smub.OUTPUT_ON --Enable output
delay(0.001) --Delay
smub.source.leveli = l_ib1 --Program new source value
delay(0.001) --Source delay
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Appendix A
Scripts
--l_comp_val = Check_Comp() --check compliance
if l_comp_val == true then --If unit is in compliance, end
smua.source.output = smua.OUTPUT_OFF --Disable output
smub.source.output = smub.OUTPUT_OFF --Disable output
smua.source.levelv = 0 --Return source to 0
smub.source.leveli = 0 --Return source to 0
else
l_ic_meas1 = smua.measure.i() --Measure Ic 1
smub.source.leveli = l_ib2 --Program new source value
l_ic_meas2 = smua.measure.i() --Measure Ic 2
l_beta_data = (l_ic_meas2 - l_ic_meas1)/(l_ib2 - l_ib1) --Calculate gain
print(“”) –
print(“Ib 1(A) “, “Ic 1(A) “, “Ib 2(A) “, “Ic 2(A) “)
print(l_ib1, l_ic_meas1, l_ib2, l_ic_meas2) --Print Ib and Ic data
print(“”) -
print(“Differential Gain”)
print(l_beta_data) --Print gain
end --ifelse
smua.source.output = smua.OUTPUT_OFF --Disable output
smub.source.output = smub.OUTPUT_OFF --Disable output
end --function AC_Gain()
function Check_Comp() --Function checks state of compliance, if true, prints warning and
returns
--to run_test()
local l_comp_val = false --Initialize local variable
l_comp_val = smua.source.compliance --Check compliance
if l_comp_val == true then
print(“”)
print(“SMU Source in Compliance!”)
print(“Ensure proper connections, stable device, and settings are correct”)
print(“Rerun Test”)
print(“”)
end --if
A-38
return l_comp_val
Appendix A
Scripts
end --function Check_Comp()
--AC_Gain()
Program 8. Transistor Leakage (ICEO)
--[[
Iceo(): USES TABLES
This program sweeps the voltage on the collector/emitter (VCE) of a BJT with an open base.
The VCEO and ICEO values are then printed.
Required equipment:
(1) Single-channel Keithley Series 2600 System SourceMeter instrument
(1) 2N3904NPN transistor
Running this script creates functions that can be used to measure open base voltage and
current characteristics of transistors. The default values are for an NPN transistor type
2N3904.
The functions created are:
1. Iceo(vstart, vstop, vsteps)
--Default values vstart = 0V, vstop = 10V, vsteps = 100
2. Print_Data(vsteps, ce_volt,ce_curr)
See detailed information listed in individual functions.
1) From Test Script Builder
- At the TSP> prompt in the Instrument Control Panel, type Vceo()
2) From an external program
- Send the entire program text as a string using standard GPIB Write calls.
Rev1: JAC 6.12.2007
]]--
------------------ Keithley TSP Function -----------------function Iceo(vstart, vstop, vsteps) --Configure SMUA to perform a voltage
--sweep from start to stop in a user-defined number on the collector/emitter of a BJT with
an open base. The collector --current (Iceo) is measured at each voltage value.
--Returns programmed voltage and measured current values.
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Appendix A
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--Global variables
local l_irange = 100E-6 --Base current source range
local l_vcmpl = 1 --Base source compliance
local l_vrange = 40 --Collector-emitter voltage source range
local l_icmpl = 100E-3 --Collector-emitter source compliance
--Shared local variables
local l_nplc = 1 --Integration rate of measurement
--Local sweep variables
local l_vstart = vstart --Collector-emitter sweep start voltage
local l_vstop = vstop --Collector-emitter sweep stop voltage
local l_vsteps = vsteps --Number of steps in sweep
--Default values and level check
local l_i = 1 --Iteration variable
if (l_vstart == nil) then --Use default value
l_vstart = 0
end --if
if (l_vstart > 100E-3) then --Coerce value
l_vstart = 100E-3
end --if
if (l_vstop == nil) then --Use default value
l_vstop = 10
end --if
if (l_vstop > 40) then --Coerce value
l_vstop = 40
end --if
if (l_vsteps == nil) then --Use default value
l_vsteps = 100
end --if
if (l_vsteps > 2E+2) then --Coerce value
l_vsteps = 2E+2
end --if
local l_vstep = (l_vstop - l_vstart)/ (l_vsteps - 1) --Voltage step size
local l_vsource_val = l_vstart --Source value during sweep
--Data tables
local l_ce_volt = {} --Create data table for collector-emitter measured voltage
local l_ce_curr = {} --Create data table for collector-emitter measured current
A-40
smua.reset() --Reset SMU
Appendix A
Scripts
errorqueue.clear() --Clear the error queue
--Configure Collector/Emitter (SMUA) source and measure settings
smua.source.func = smua.OUTPUT_DCVOLTS
smua.source.autorangev = smua.AUTORANGE_ON --Enable source autorange
smua.source.levelv = 0
--Source 0V
smua.source.limiti = l_icmpl --Set compliance level
smua.measure.autorangei = smua.AUTORANGE_ON --Enable measure autorange
smua.measure.autozero = smua.AUTOZERO_AUTO
smua.measure.nplc = l_nplc --Measurement integration rate
smua.source.output = smua.OUTPUT_ON --Enable Output
smua.source.levelv = l_vsource_val --Program source value
--Execute sweep
for l_i = 1, l_vsteps do
delay(0.01)
l_ce_volt[l_i] = l_vsource_val --Save programmed voltage
l_ce_curr[l_i] = smua.measure.i() --Measure current
l_vsource_val = l_vsource_val + l_vstep --Calculate new source value
smua.source.levelv = l_vsource_val --Increment source
end--for
smua.source.output = smua.OUTPUT_OFF --Disable output
smua.source.levelv = 0 --Return source to bias level
Print_Data(l_vsteps,l_ce_volt, l_ce_curr)
end--function Vceo()
function Print_Data(vsteps, ce_volt,ce_curr)
--Print Data to output queue
--Local Variables
local l_vsteps = vsteps
local l_i = 1 --Iteration variable
local l_ce_volt = ce_volt
local l_ce_curr = ce_curr
print(“”)
print(“Vceo (V)”,”Iceo (A)”)
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Scripts
for l_i = 1, l_vsteps do
print(l_ce_volt[l_i], l_ce_curr[l_i])
end --for
end --function Print_Data()
--Iceo()
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Section 4. FET Tests
Program 9. Common-Source Characteristics
--[[
FET_Comm_Source(): USES TABLES
This program applies a bias to the gate-source of an FET (VGS) and sweeps voltage on the
drain-source (VDS). The VDS and ID values at each VGS bias are then printed.
Required equipment:
(1) Dual-channel Keithley Series 2600 System SourceMeter instrument
(1) SD210 N-Channel MOSFET
Running this script creates functions that can be used to measure the common source
characteristics of
FETs. The default values are for an N-channel MOSFET type SD210.
The functions created are:
1. FET_Comm_Source(vgsstart, vgsstop, vgssteps, vdsstart, vdsstop, vdssteps)
--Default values vgsstart = 0, vgsstop = 10V, vgssteps = 5, vdstart = 0V,
vdstop = 10V, vdsteps = 100
2. Print_Data(vgssteps,vdssteps, vds_data,Id_data, vgs_data)
See detailed information listed in individual functions.
1) From Test Script Builder
- At the TSP> prompt in the Instrument Control Panel, type FET_Comm_Source()
2) From an external program
- Send the entire program text as a string using standard GPIB Write calls.
Rev1: JAC 6.18.2007
]]--
------------------ Keithley TSP Function -----------------function FET_Comm_Source(vgsstart, vgsstop, vgssteps, vdsstart, vdsstop, vdssteps)
--Configure SMUB to source a bias
--voltage on the gate-source (Vgs) and SMUA performs a voltage sweep on the drain-source
(Vds) from start to stop in a --user-defined number of steps. SMUB then increments to next
bias value and continues to the stop value.
--Returns measured Vgs, Vds, and Id values.
--Global variables
local l_vrange = 40 --
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Appendix A
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local l_icmpl = 100E-3 -
--Shared local variables
local l_nplc = 1 --Integration rate of measurement
--Local sweep variables
local l_vgsstart = vgsstart --Gate-source sweep start voltage
local l_vgsstop = vgsstop --Gate-source sweep stop voltage
local l_vgssteps = vgssteps --Number of steps in sweep
local l_vdsstart = vdsstart --Drain-source sweep start voltage
local l_vdsstop = vdsstop --Drain-source sweep stop voltage
local l_vdssteps = vdssteps --Number of steps in sweep
--Default values and level check
if (l_vgsstart == nil) then --Use default value
l_vgsstart = 0
end --if
if (l_vgsstart > 10) then --Coerce value
l_vgsstart = 10
end --if
if (l_vgsstop == nil) then --Use default value
l_vgsstop = 10
end --if
if (l_vgsstop > 10) then --Coerce value
l_vgsstop = 10
end --if
if (l_vgssteps == nil) then --Use default value
l_vgssteps = 5
end --if
if (l_vgssteps > 100) then --Coerce value
l_vgssteps = 100
end --if
local l_vgsstep = (l_vgsstop - l_vgsstart)/ (l_vgssteps - 1) --Vgs step size
local l_vgssource_val = l_vgsstart --Source value during sweep
local l_vgs_iteration = 1 --Iteration variable
if (l_vdsstart == nil) then --Use default value
l_vdsstart = 0
end --if
if (l_vdsstart > 10) then --Coerce value
l_vdsstart = 10
end --if
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if (l_vdsstop == nil) then --Use default value
l_vdsstop = 10
end --if
if (l_vdsstop > 40) then --Coerce value
l_vdsstop = 40
end --if
if (l_vdssteps == nil) then --Use default value
l_vdssteps = 100
end --if
if (l_vdssteps > 2E+2) then --Coerce value
l_vdssteps = 2E+2
end --if
local l_vdsstep = (l_vdsstop - l_vdsstart)/ (l_vdssteps - 1) --Voltage step size
local l_vdssource_val = l_vdsstart --Source value during sweep
local l_vds_iteration = 1 --Iteration variable
--Data tables
local l_vgs_data = {} --Create data table for sourced gate-source voltage
local l_vds_data = {} --Create data table for drain-source voltage
local l_id_data = {} --Create data table for drain-source measured current
smua.reset() --Reset SMU
smub.reset() --Reset SMU
errorqueue.clear() --Clear the error queue
--Configure Drain-Source (SMUA) source and measure settings
smua.source.func = smua.OUTPUT_DCVOLTS
smua.source.autorangev = smua.AUTORANGE_ON --Enable source autorange
smua.source.levelv = 0
smua.source.limiti = l_icmpl
smua.measure.autorangei = smua.AUTORANGE_ON --Enable measure autorange
smua.measure.autozero = smua.AUTOZERO_AUTO
smua.measure.nplc = l_nplc --Measurement integration rate
smua.source.output = smua.OUTPUT_ON --Enable Output
--Configure Gate-Source (SMUB) source and measure settings
smub.source.func = smub.OUTPUT_DCVOLTS
smub.source.autorangev = smub.AUTORANGE_ON --Enable source autorange
smub.source.levelv = 0
smub.source.limiti = l_icmpl
smub.measure.autorangei = smub.AUTORANGE_ON --Enable measure autorange
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Appendix A
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smub.measure.autozero = smub.AUTOZERO_AUTO
smub.measure.nplc = l_nplc --Measurement integration rate
smub.source.output = smub.OUTPUT_ON --Enable Output
--Execute sweep
for l_vgs_iteration = 1, l_vgssteps do
smub.source.levelv = l_vgssource_val
l_vds_data[l_vgs_iteration] = {} --Create new row in table
l_id_data[l_vgs_iteration] = {} --Create new row in table
l_vgs_data[l_vgs_iteration] = smub.measure.v() --Measure gate-source voltage
for l_vds_iteration = 1,l_vdssteps do
if (l_vds_iteration == 1) then --Intialize start source value
l_vdssource_val = l_vdsstart
end --if
--delay(1)
l_vds_data[l_vgs_iteration][l_vds_iteration] = smua.measure.v()
--Measure sourced voltage
l_id_data[l_vgs_iteration][l_vds_iteration] = smua.measure.i()
--Measure current
l_vdssource_val = l_vdssource_val + l_vdsstep --Calculate new source
value
if (l_vds_iteration == l_vdssteps) then --Reinitialize voltage value
after last iteration
l_vdssource_val = l_vdsstart
end --if
smua.source.levelv = l_vdssource_val --Increment source
end --for
l_vgssource_val = l_vgssource_val + l_vgsstep --Calculate new source value
end--for
A-46
smua.source.output = smua.OUTPUT_OFF --Disable output
smub.source.output = smub.OUTPUT_OFF --Disable output
smua.source.levelv = 0 --Return source to bias level
smub.source.leveli = 0 --Return source to bias level
Appendix A
Scripts
Print_Data(l_vgssteps,l_vdssteps, l_vds_data, l_id_data, l_vgs_data)
end--function FET_Comm_Source()
function Print_Data(vgssteps,vdssteps, vds_data,id_data, vgs_data)
--Print Data to output queue
--Local Variables
local l_vgssteps = vgssteps
local l_vdssteps = vdssteps
local l_vgs_iteration = 1 --Iteration variable
local l_vds_iteration = 1 --Iteration variable
local l_vds_data = vds_data
local l_id_data = id_data
local l_vgs_data = vgs_data
for l_vgs_iteration = 1, l_vgssteps do
print(“”)
print(“Gate-source Bias (V)”, l_vgs_data[l_vgs_iteration])
print(“Drain-source Voltage (V)”,”Drain-source Current (A)”)
for l_vds_iteration = 1, l_vdssteps do
print(l_vds_data[l_vgs_iteration][l_vds_iteration], l_id_data[l_vgs_
iteration][l_vds_iteration])
end --for
end --for
end --function Print_Data()
--FET_Comm_Source()
A-47
Appendix A
Scripts
Program 10. Transconductance
--[[
Transconductance():
This program sources a voltage bias on a drain-source of a FET (VDS), sources a voltage on
the gate (VGS1), and measures the drain-source current (ID1). Then, another source value
(VGS2) is sourced and the IDS2 is measured.
The transconductance (gfs) is then calculated by taking the change in Ids divided by the
change in VGS.
The drain-source voltage (VDS), Transconductance (gfs), gate-source voltage (VGS), and
drain-source current (ID) are returned.
Required equipment:
(1) Dual-channel Keithley Series 2600 System SourceMeter instrument
(1) SD210 N-channel FET
Running this script creates functions that can be used to create a transconductance test
of FETs. The default values are for an N-channel SD210 FET.
The functions created are:
1. Transconductance(vgsstart, vgsstop, vgssteps, vdsbias)
--Default values vgsstart = 0V, vgsstop = 5V, vgssteps = 100, vdsbias =
10V
2. Check_Comp()
See detailed information listed in individual functions.
To run:
1) From Test Script Builder
- Right-click in the program window, select “Run as TSP”
- At the TSP> prompt in the Instrument Control Panel, type Transconductance()
2) From an external program
- Send the entire program text as a string using standard GPIB Write calls.
Rev1: JAC 6.18.2007
]]------------------- Keithley TSP Function -----------------function Transconductance(vgsstart, vgsstop, vgssteps, vdsbias)--Configure SMUA to source a
user-defined voltage on the
A-48
Appendix A
Scripts
--drain-source (Vds) while SMUB performs a fixed voltage bias (Vgs)on the gate-source and
the Ids is measured.
--SMUB then steps to the next base current and the Ic is measured. --Returns measured Vds, Vgs, Id, gfs values are returned.
--Global variables
local l_icmpl = 100E-3 --Source compliance
--Shared local variables
local l_nplc = 1 --Integration rate of measurement
--Local sweep variables
local l_vgsstart = vgsstart --Vgs start voltage
local l_vgsstop = vgsstop --Vgs sweep stop voltage
local l_vgssteps = vgssteps --Number of steps in sweep
local l_vdsbias = vdsbias --Drain-source voltage
--Default values and level check
if (l_vgsstart == nil) then --Use default value
l_vgsstart = 0
end --if
if (l_vgsstart > 10) then --Coerce value
l_vgsstart = 10
end --if
if (l_vgsstop == nil) then --Use default value
l_vgsstop = 5
end --if
if (l_vgsstop > 10) then --Coerce value
l_vgsstop = 10
end --if
if (l_vgssteps == nil) then --Use default value
l_vgssteps = 20
end --if
if (l_vgssteps > 100) then --Coerce value
l_vgssteps = 100
end --if
local l_vgsstep = (l_vgsstop - l_vgsstart)/ (l_vgssteps - 1) --Vbe step size
local l_vgssource_val = l_vgsstart --Source value during sweep
local l_i = 1 --Iteration variable
if (l_vds_bias == nil) then --Use default value
l_vds_bias = 10
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Appendix A
Scripts
end --if
if (l_vds_bias > 10) then --Coerce value
l_vds_bias = 10
end --if
--Data tables
local l_vgs = {} --Create data table for gate-source voltage
local l_id = {} --Create data table for drain-source current
local l_gfs = {} --Create data table for transconductance (gfs)
smua.reset() --Reset SMU
smub.reset() --Reset SMU
errorqueue.clear() --Clear the error queue
--Configure Collector/Emitter (SMUA) source and measure settings
smua.source.func = smua.OUTPUT_DCVOLTS
smua.source.autorangev = smua.AUTORANGE_ON --Enable source autorange
smua.source.levelv = 0
smua.source.limiti = l_icmpl
smua.measure.autorangei = smua.AUTORANGE_ON --Enable measure autorange
smua.measure.autozero = smua.AUTOZERO_AUTO
smua.measure.nplc = l_nplc --Measurement integration rate
smua.source.output = smua.OUTPUT_ON --Enable Output
--Configure Base (SMUB) source and measure settings
smub.source.func = smub.OUTPUT_DCVOLTS
smub.source.autorangev = smub.AUTORANGE_ON --Enable source autorange
smub.source.levelv = 0
smub.source.limiti = l_icmpl
smub.measure.autorangev = smub.AUTORANGE_ON --Enable measure autorange
smub.measure.autozero = smub.AUTOZERO_AUTO
smub.measure.nplc = l_nplc --Measurement integration rate
smub.source.output = smub.OUTPUT_ON --Enable Output
smua.source.levelv = l_vds_bias
--Execute sweep
for l_i = 1,l_vgssteps do
if (l_i == 1) then --Intialize start source value
l_vgssource_val = l_vgsstart
end --if
--delay(1)
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Appendix A
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l_vgs[l_i] = smub.measure.v() --Measure Vgs
l_id[l_i] = smua.measure.i() --Measure Id
l_vgssource_val = l_vgssource_val + l_vgsstep --Calculate new source value
if (l_i == l_vgssteps) then --Reinitialize voltage value after last
iteration
l_vgssource_val = l_vgsstart
end --if
smub.source.levelv = l_vgssource_val --Increment source
end --for
smua.source.output = smua.OUTPUT_OFF --Disable output
smub.source.output = smub.OUTPUT_OFF --Disable output
smua.source.levelv = 0 --Return source to bias level
smub.source.levelv = 0 --Return source to bias level
Print_Data(l_vds_bias, l_vgssteps, l_vgs, l_id)
end--function Transconductance()
function Print_Data(vdsbias, vgssteps,vgs, id)
--Calculate Gfs value and print data to output queue
--Local Variables
local l_vds_bias = vdsbias --Vds bias value
local l_vgs_steps = vgssteps --Number of steps in Vgs sweep
local l_vgs = vgs --Gate-source Voltage data
local l_id = id --Drain-source current data
local l_gfs = {} --Table for Transconductance calculations
local l_i = 1 --Iteration variable
--Calculate gfs values and populate table
for l_i = 1,l_vgs_steps do
if (l_i ~= 1) then --If not the first iteration, calculate gfs
l_gfs[l_i] = (l_id[l_i] - l_id[l_i - 1])/(l_vgs[l_i] - l_vgs[l_i - 1])
--gfs = dId/dVgs
end--if
end --for
l_i = 1 --Reinitialize Vgs iteration variable
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print(“”)
print(“Vds”, l_vds_bias)
print(“Vgs (V)”,”Id (A)”,”gfs (s)”)
for l_i = 2, l_vgs_steps do
print(l_vgs[l_i],l_id[l_i], l_gfs[l_i])
end --for
end --function Print_Data()
--Transconductance()
Program 11. Threshold
Program 11A. Threshold (Search)
--[[
FET_Thres_Search():
This program performs a binary search on the gate-source voltage (VGS) of an FET at a fixed
drain-source voltage (VDS) and searches for a target drain-source current (ID). If the
specified Id is found within the maximum number of iterations, the threshold voltage (VTH)
and drain-source (ID) currents are measured and printed.
If the maximum number of iterations are reached, the program is aborted.
Required equipment:
(1) Dual-channel Keithley Series 2600 System SourceMeter instrument
(1) SD210 N-Channel FET
Running this script creates functions that can be used to create a threshold search of
FETs. The default values are for an NPN transistor type 2N5089.
The functions created are:
1. FET_Thres_Search(vdssource, lowvgs, highvgs, targetid)
--Default values vdssource = 1V, lowvgs = 0.5, highvgs = 2, targetid =
1e-6A
2. Check_Comp()
See detailed information listed in individual functions.
To run:
1) From Test Script Builder
- Right-click in the program window, select “Run as TSP”
- At the TSP> prompt in the Instrument Control Panel, type FET_Thres_Search()
2) From an external program
- Send the entire program text as a string using standard GPIB Write calls.
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Rev1: JAC 6.26.2007
]]--
------------------ Keithley TSP Function -----------------function FET_Thres_Search(vdssource, lowvgs, highvgs, targetid) --Configure SMUA to source
a user-defined voltage on
--the drain-source (Vds) while SMUB sources a voltage on --the gate-source (Vgs). VGS is
varied using a binary
--search algorithm between a maximum and minimum Vgs value, and the drain-source current
(Id) is measured.
--If measured value is outside the tolerance, search is performed again until the value
falls within the
--specified range or the iteration limit is reached.
--Returns measured Vds, Vth, and Id.
local l_k --binary search loop count variable
local l_k_max = 20 --Maximum loop counts
local l_vds_source = vdssource --vdssource value
local l_high_vgs = highvgs --Start Ib high limit
local l_low_vgs = lowvgs --Start Ib lo limit
local l_target_id = targetid --Target Ic for binary search
local l_nplc = 1
local l_vgs_source = 0--Gate-sourced voltage
local l_id_meas --Drain-source measured voltage
--Default values and level check
if (l_vds_source == nil) then --Use default value
l_vds_source = 0.5
end --if
if (l_low_vgs == nil) then --Use default value
l_low_vgs = 0.5
end --if
if (l_high_vgs == nil) then --Use default value
l_high_vgs = 1.1
end --if
if (l_target_id == nil) then --Use default value
l_target_id = 1e-6
end --if
smua.reset() --Reset SMU
smub.reset() --Reset SMU
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errorqueue.clear() --Clear the error queue
smua.measure.nplc = l_nplc --Measurement integration rate
smub.measure.nplc = l_nplc --Measurement integration rate
smua.source.func = smua.OUTPUT_DCVOLTS
smua.source.autorangev = smua.AUTORANGE_ON --Enable source autorange
smua.source.limiti = (100 * l_target_id) --Set compliance value
smua.measure.autorangev = smua.AUTORANGE_ON --Enable measure autorange
smub.source.func = smub.OUTPUT_DCVOLTS
smub.source.autorangev = smub.AUTORANGE_ON --Enable source autorange
smub.source.limiti = l_high_vgs
smub.source.limitv = 6
smub.measure.autorangev = smub.AUTORANGE_ON --Enable measure autorange
--Start test
smua.source.levelv = l_vds_source --Set source level
smub.source.levelv = 0 --Set source level
smua.source.output = smua.OUTPUT_ON --Enable output
smub.source.output = smub.OUTPUT_ON --Enable output
delay(0.001) --Delay
l_comp_val = Check_Comp() --check compliance
if l_comp_val == true then --If unit is in compliance, end
smua.source.output
smub.source.output
smua.source.levelv
smub.source.levelv
else
= smua.OUTPUT_OFF --Disable output
= smub.OUTPUT_OFF --Disable output
= 0 --Return source to 0
= 0 --Return source to 0
--Search for the right base current
l_k = 0
repeat --Repeat search until measured Ic is within 5% of target, or iteration
maximum reached, or compliance.
l_k = l_k + 1 --Increment
l_vgs_source = ((l_high_vgs-l_low_vgs)/2) + l_low_vgs --Determine source
value (Binary Search)
smub.source.levelv = l_vgs_source --Program new source value
delay(0.01) --Source delay
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l_comp_val = Check_Comp() --check compliance
if l_comp_val == true then --If unit is in compliance, end
smua.source.output = smua.OUTPUT_OFF --Disable output
smub.source.output = smub.OUTPUT_OFF --Disable output
smua.source.levelv = 0 --Return source to 0
smub.source.levelv = 0 --Return source to 0
else
l_id_meas = smua.measure.i() --Measure Id
if (l_target_id < l_id_meas) then --Compare measurement with
target value
l_high_vgs = l_vgs_source
else
l_low_vgs = l_vgs_source
end --end if
end --ifelse
if l_id_meas == nil then --If no measurement taken, initialize to 0 to avoid
arithmatic error
--in until statement below
l_id_meas = 0
end --if
until ((math.abs(l_id_meas - l_target_id) < (0.05*l_target_id))or(l_k>l_k_max))
or(l_comp_val == true) -
--iteration limit reached
if (l_k > l_k_max) then
print(“Iteration Limit Reached!!”)
end --end if
smua.source.output = smua.OUTPUT_OFF --Disable output
smub.source.output = smub.OUTPUT_OFF --Disable output
print(“Id Data:”, l_id_meas) --Print Id data
print(“Vgs Data:”, l_vgs_source) --Print Vgs
print(“Vds Data:”,l_vds_source) --Print Vds
end --ifelse
end--function FET_Thres_Search()
function Check_Comp() --Function checks state of compliance, if true, prints warning and
returns
--to run_test()
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local l_comp_val = false --Initialize local variable
l_comp_val = smua.source.compliance --Check compliance
if l_comp_val == true then
print(“”)
print(“SMU Source in Compliance!”)
print(“Ensure proper connections, stable device, and settings are correct”)
print(“Rerun Test”)
print(“”)
end --if
return l_comp_val
end --function Check_Comp()
--FET_Thres_Search()
Program 11B. Threshold (Fast)
--[[
FET_Thres_Fast()
This program applies a bias to the drain-source of an FET (VDS) and sweeps current on the
drain-source (ID) and the threshold voltage (VTH) at each ID value is measured.
*NOTE: Due to connection scheme, negative values are to be programmed for the sourced
values. The absolute value of the measurements and sourced values are printed.
Required equipment:
(1) Dual-channel Keithley Series 2600 System SourceMeter instrument
(1) SD210 N-channel FET
Running this script creates functions that can be used to measure the threshold of FETs.
The default values are for an N-channel FET type SD210.
The functions created are:
1. FET_Thres_Fast(vdssource, istart, istop, isteps)
--Default values vdssource = 0.5V, istart = 0.5uA, istop = 1uA, isteps =
10
2. Print_Data(isteps, drain_curr, thres_volt)
See detailed information listed in individual functions.
1) From Test Script Builder
- At the TSP> prompt in the Instrument Control Panel, type FET_Thres_Fast()
2) From an external program
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- Send the entire program text as a string using standard GPIB Write calls.
Rev1: JAC 6.26.2007
]]------------------- Keithley TSP Function -----------------function FET_Thres_Fast(vdssource, istart, istop, isteps) --Configure SMUB to source a bias
current
--on the drain-source (Id) and SMUA performs a voltage sweep on the drain-source (Vds)
from start to
--stop in a user-defined number of steps.
--Returns Vth, Vds, and Id values.
--Global variables
local l_irange = 100e-6 --Drain current source range
local l_vcmpl = 11 --Drain source compliance
local l_vrange = 40 --Drain-source voltage source range
local l_icmpl = 100e-3 --Drain source compliance
--Shared local variables
local l_nplc = 1 --Integration rate of measurement
--Local sweep variables
local l_istart = istart --Drain sweep start current
local l_istop = istop --Drain sweep stop current
local l_isteps = isteps --Number of steps in sweep
local l_vds_source = vdssource --Vds source value
--Default values and level check
if (l_vds_source == nil) then --Use default value
l_vds_source = -0.5
end --if
if (l_vds_source > 0) then --Coerce value
l_vds_source = -l_vds_source
end --if
if (l_istart == nil) then --Use default value
l_istart = -500e-9
end --if
if (l_istart > 0) then --Coerce value
l_istart = -l_istart
end --if
if (l_istop == nil) then --Use default value
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l_istop = -1e-6
end --if
if (l_istop > 0) then --Coerce value
l_istop = -i_stop
end --if
if (l_isteps == nil) then --Use default value
l_isteps = 10
end --if
if (l_isteps > 100) then --Coerce value
l_isteps = 100
end --if
local l_istep = (l_istop - l_istart)/ (l_isteps - 1) --Current step size
local l_isource_val = l_istart --Source value during sweep
local l_i = 1 --Iteration variable
--Data tables
local l_thres_volt = {} --Create data table for threshold voltage
local l_drain_curr = {} --Create data table for emitter current
smua.reset() --Reset SMU
smub.reset() --Reset SMU
errorqueue.clear() --Clear the error queue
--Configure emitter current (SMUA) source and measure settings
smua.source.func = smua.OUTPUT_DCVOLTS
smua.source.autorangev = smua.AUTORANGE_ON --Enable source autorange
smua.source.levelv = 0
smua.source.limiti = l_icmpl
smua.sense = smua.SENSE_REMOTE --Enable Remote (4-wire) sensing
smua.source.output = smua.OUTPUT_ON --Enable Output
--Configure collector/emitter (SMUB) source and measure settings
smub.source.func = smub.OUTPUT_DCAMPS
smub.source.autorangev = smub.AUTORANGE_ON --Enable source autorang
smub.source.levelv = 0
smub.source.limitv = l_vcmpl
smub.measure.autorangev = smub.AUTORANGE_ON --Enable measure autorange
smub.measure.autozero = smub.AUTOZERO_AUTO
smub.measure.nplc = l_nplc --Measurement integration rate
smub.source.output = smub.OUTPUT_ON --Enable Output
smua.source.levelv = l_vds_source --Program source
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--Execute sweep
for l_i = 1, l_isteps do
smub.source.leveli = l_isource_val
delay(0.01)
l_thres_volt[l_i] = smub.measure.v() --Measure threshold voltage (Vt)
l_drain_curr[l_i] = smua.measure.i() --Measure drain current
l_isource_val = l_isource_val + l_istep --Calculate new source value
end--for
smua.source.output = smua.OUTPUT_OFF --Disable output
smub.source.output = smub.OUTPUT_OFF --Disable output
smua.source.levelv = 0 --Return source to bias level
smub.source.leveli = 0 --Return source to bias level
Print_Data(l_isteps, l_drain_curr, l_thres_volt, l_vds_source)
end--function DC_Gain_Fast()
function Print_Data(isteps, drain_curr, thres_volt, vdssource)
--Print Data to output queue
--Local Variables
local l_isteps = isteps
local l_i = 1 --Iteration variable
local l_drain_curr = drain_curr --Drain current table
local l_thres_volt = thres_volt --Threshold voltage table
local l_vds_source = vdssource --Drain-source voltage value
print(“”)
print(“Drain-source Voltage (V)”)
print(math.abs(l_vds_source))
print(“”)
print(“Threshold Voltage (V)”, “Drain Current (A)”)
for l_i = 1, l_isteps do
print(math.abs(l_thres_volt[l_i]), math.abs(l_drain_curr[l_i]))
end --for
end --function Print_Data()
--FET_Thres_Fast()
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Section 5. Using Substrate Bias
Program 12. Substrate Current vs. Gate-Source Voltage (FET ISB vs. VGS)
--[[
FET_Isb_Vgs():
This program applies a voltage bias on the drain-source (VDS), a voltage bias on the
substrate-source (VSB) of an FET, then sweeps the gate-source voltage (VGS) from a userdefined stop, through a defined number of steps.
At each point, the VGS, ID, and ISB are measured and the data is printed.
Required equipment:
(1) Dual-channel Keithley Series 2600 System SourceMeter instrument
(1) Keithley Model 2636 System Sourcemeter instrument (Required for low current
measurement)
(1) Crossover Ethernet Cable
(1) SD210 N-channel FET
- Connect the single-channel SourceMeter instrument to the dual-channel master using a
crossover Ethernet cable.
- Connect the test fixture to both units using appropriate cables.
- Turn on the SourceMeter instruments and allow the units to warm up for two hours for
rated accuracy.
Configure the TSP-Link communications for each instrument:
Slave: A single-channel instrument such as the Model 2601, 2611, or 2635.
1. Press the MENU key to access MAIN MENU.
2. Select the COMMUNICATION menu. (Skip this step if the Series 2600 instruments
used have firmware Revision 1.4.0 or later installed.)
3. Select the TSPLINK_CFG menu. (If the Series 2600 instruments used have firmware
Revision 1.4.0 or later installed, the menu name should be TSPLINK.)
4. Select the NODE menu.
5. Set the NODE number to 2 and press ENTER.
Master: A dual-channel instrument such as the Model 2602, 2612, or 2636.
1. Press the MENU key to access MAIN MENU.
2. Select the COMMUNICATION menu. (Skip this step if the Series 2600 instruments
used have firmware Revision 1.4.0 or later installed.)
3. Select the TSPLINK_CFG menu. (If the Series 2600 instruments used have firmware
Revision 1.4.0 or later installed, the menu name should be TSPLINK.)
4. Select the NODE menu.
5. Set the NODE number to 1 for the Master and press ENTER.
6. Select the TSPLINK_CFG menu. (If the Series 2600 instruments used have firmware
Revision 1.4.0 or later installed, the menu name should be TSPLINK.)
7. Select the RESET to initialize the TSP-Link.
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Running this script creates functions that can be used to measure the Isb v. Vgs
characteristics of FETs.
The functions created are:
1. FET_Isb_Vgs(vdssource, vsbsource,vgsstart,vgsstop, vgssteps) --Default values vdssource
= 1V,
--vgsstart = 0V,vgsstop = 10V, vgssteps = 10
2. Print_Data(l_vgs_steps, l_id_curr, l_vgs_volt,l_isb_curr)
See detailed information listed in individual functions.
To run:
1) From Test Script Builder
- Right-click in the program window, select “Run as TSP”
- At the TSP> prompt in the Instrument Control Panel, type FET_Isb_Vgs()
2) From an external program
- Send the entire program text as a string using standard GPIB Write calls.
Rev1: JAC 5.22.2007
]]--
------------------ Keithley TSP Function -----------------function FET_Isb_Vgs(vdssource, vsbsource,vgsstart,vgsstop, vgssteps) --Configure node 1
SMUA to source drain-source
--voltage (Vds), node 2 SMUA to apply a voltage bias on the substrate-source (Vsb)and
perform a voltage sweep from
--start to stop in user-defined steps using node 1 SMUB on the gate-source (Vgs). At each
point, Vgs and Isb are
--measured and printed.
--Global variables
local l_vds_source = vdssource --Drain-source source voltage
local l_vsb_source = vsbsource --Substrate-source bias voltage
local l_icmpl = 100E-3 --Source compliance
--Local sweep variables
local l_vgs_start = vgsstart --Gate-source sweep start voltage
local l_vgs_stop = vgsstop --Gate-source sweep stop voltage
local l_vgs_steps = vgssteps --Number of steps in sweep
--Shared local variables
local l_nplc = 1 --Integration rate of measurement
--Default values and level check
if (l_vds_source == nil) then --Use default value
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l_vds_source = 1
end --if
if (l_vds_source > 1) then --Coerce value
l_vds_source = 1
end --if
if (l_vsb_source == nil) then --Use default value
l_vsb_source = -1
end --if
if (l_vsb_source > 0 ) then --Coerce value
l_vsb_source = -1
end --if
if (l_vgs_start == nil) then --Use default value
l_vgs_start = 0
end --if
if (l_vgs_start > 10) then --Coerce value
l_vgs_start = 10
end --if
if (l_vgs_stop == nil) then --Use default value
l_vgs_stop = 10
end --if
if (l_vgs_stop > 10) then --Coerce value
l_vgs_stop = 10
end --if
if (l_vgs_steps == nil) then --Use default value
l_vgs_steps = 10
end --if
if (l_vgs_steps > 1E3) then --Coerce value
l_vgs_steps = 1E3
end --if
local l_step = (l_vgs_stop - l_vgs_start)/ (l_vgs_steps - 1) --Current step size
local l_source_val = l_vgs_start --Source value during sweep
local l_i = 1 --Iteration variable
--Data tables
local l_isb_curr = {} --Create data table for substrate-source current
local l_id_curr = {} --Create data table for drain-source current
local l_vgs_volt = {} --Create data table for gate-substrate voltage
local l_vds_volt = {} --Create data table for drain-substrate voltage
node[1].smua.reset() --Reset SMU
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node[1].smub.reset() --Reset SMU
node[2].smua.reset() --Reset SMU
errorqueue.clear() --Clear the error queue
--Configure drain-source SMU (TSP-Link Node[1] SMUA) source and measure settings
node[1].smua.source.func = node[1].smua.OUTPUT_DCVOLTS
node[1].smua.source.autorangev = node[1].smua.AUTORANGE_ON --Enable source
autorange
node[1].smua.source.levelv = l_vds_source
node[1].smua.source.limiti = l_icmpl
node[1].smua.measure.autorangev = node[1].smua.AUTORANGE_ON --Enable measure
autorange
node[1].smua.measure.nplc = l_nplc --Measurement integration rate
--Configure gate-source SMU (TSP-Link Node[1] SMUB) source and measure settings
node[1].smub.source.func = node[1].smub.OUTPUT_DCVOLTS
node[1].smub.source.autorangev = node[1].smub.AUTORANGE_ON --Enable source
autorange
node[1].smub.source.levelv = l_vds_source
node[1].smub.source.limiti = l_icmpl
node[1].smub.measure.autorangev = smub.AUTORANGE_ON --Enable measure autorange
node[1].smub.measure.nplc = l_nplc --Measurement integration rate
--Configure substrate-source SMU (TSP-Link Node[2] SMUA) source and measure settings
node[2].smua.source.func = node[2].smua.OUTPUT_DCVOLTS
node[2].smua.source.autorangev = node[2].smua.AUTORANGE_ON --Enable source
autorange
node[2].smua.source.levelv = l_vsb_source
node[2].smua.source.limiti = l_icmpl
node[2].smua.measure.autorangev = node[2].smua.AUTORANGE_ON --Enable measure
autorange
node[2].smua.measure.nplc = l_nplc --Measurement integration rate
node[1].smua.source.output = smua.OUTPUT_ON --Enable Output
node[1].smub.source.output = smub.OUTPUT_ON --Enable Output
node[2].smua.source.output = smua.OUTPUT_ON --Enable Output
--Execute sweep
for l_i = 1, l_vgs_steps do
--smua.source.leveli = l_source_val
delay(0.010) --Delay
l_id_curr[l_i] = node[1].smua.measure.i() --Measure drain-source current
l_vgs_volt[l_i] = node[1].smub.measure.v() --Measure gate-source voltage
l_isb_curr[l_i] = node[2].smua.measure.i() --Measure substrate-source
current
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l_source_val = l_source_val + l_step --Calculate new source value
node[1].smub.source.levelv = l_source_val --Increment source
end--for
node[1].smua.source.output = node[1].smua.OUTPUT_OFF --Disable output
node[1].smub.source.output = node[1].smub.OUTPUT_OFF --Disable output
node[2].smua.source.output = node[2].smua.OUTPUT_OFF --Disable output
Print_Data(l_vgs_steps, l_id_curr, l_vgs_volt,l_isb_curr)
end--function Diode_Fwd_Chr()
function Print_Data(vgssteps,idcurr,vgsvolt,isbcurr)
--Print Data to output queue
--Local Variables
local l_vgs_steps = vgssteps
local l_id_curr = idcurr
local l_vgs_volt = vgsvolt
local l_isb_curr = isbcurr
print(“Drain-source current(A):”, “Gate-source voltage(V):”, “Substrate-source
current(A):” )
for l_i = 1, l_vgs_steps do
print(l_id_curr[l_i], l_vgs_volt[l_i], l_isb_curr[l_i])
end
end --function Print_Data()
--FET_Isb_Vgs()
Program 13. Common-Source Characteristics with Substrate Bias
--[[
FET_Comm_Source_Vsb():
This program applies a bias to the substrate-source of an FET (VSB) and a staircase sweep
on the gate-source voltage (VGS). At each VGS value, the drain-source voltage (VDS) is
also swept linearly.
At each point, the VDS and IDS are measured and printed.
Required equipment:
(1) Dual-channel Keithley Series 2600 System SourceMeter instrument
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(1) Keithley Model 2636 System Sourcemeter instrument (Required for low current
measurement)
(1) Crossover Ethernet Cable
(1) SD210 N-Channel MOSFET
- Connect
crossover
- Connect
- Turn on
accuracy.
the single-channel SourceMeter instrument to the dual-channel master using a
Ethernet cable.
the test fixture to both units using appropriate cables.
the SourceMeter instrument and allow the unit to warm up for two hours for rated
Configure the TSP-Link communications for each instrument:
Slave: A single-channel instrument such as the Model 2601, 2611, or 2635.
1. Press the MENU key to access MAIN MENU.
2. Select the COMMUNICATION menu. (Skip this step if the Series 2600 instruments
used have firmware Revision 1.4.0 or later installed.)
3. Select the TSPLINK_CFG menu. (If the Series 2600 instruments used have firmware
Revision 1.4.0 or later installed, the menu name should be TSPLINK.)
4. Select the NODE menu.
5. Set the NODE number to 2 and press ENTER.
Master: A dual-channel instrument such as the Model 2602, 2612, or 2636.
1. Press the MENU key to access MAIN MENU.
2. Select the COMMUNICATION menu. (Skip this step if the Series 2600 instruments
used have firmware Revision 1.4.0 or later installed.)
3. Select the TSPLINK_CFG menu. (If the Series 2600 instruments used have firmware
Revision 1.4.0 or later installed, the menu name should be TSPLINK.)
4. Select the NODE menu.
5. Set the NODE number to 1 for the Master and press ENTER.
6. Select the TSPLINK_CFG menu. (If the Series 2600 instruments used have firmware
Revision 1.4.0 or later installed, the menu name should be TSPLINK.)
7. Select the RESET to initialize the TSP-Link.
Running this script creates functions that can be used to measure the common source
characteristics of an N-channel MOSFET with substrate bias. The default values are for an
N-channel MOSFET type SD210.
The functions created are:
1. FET_Comm_Source_Vsb(vgsstart, vgsstop, vgssteps, vdsstart, vdsstop,
vdssteps, vsbsource)
--Default values vgsstart = 0, vgsstop = 10V, vgssteps = 5, vdstart = 0V,
vdstop = 10V,
--vdsteps = 100, vsbsource = -1V
2. Print_Data(vgssteps,vdssteps, vds_data,Id_data, vgs_data, vsbsource)
See detailed information listed in individual functions.
1) From Test Script Builder
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- At the TSP> p rompt in the Instrument Control Panel, type FET_Comm_Source_Vsb()
2) From an external program
- Send the entire program text as a string using standard GPIB Write calls.
Rev1: JAC 6.18.2007
]]---TODO: Update Node info
------------------ Keithley TSP Function -----------------function FET_Comm_Source_Vsb(vgsstart, vgsstop, vgssteps, vdsstart, vdsstop, vdssteps,
vsbsource)
--Configure node 1 SMUB to source a bias voltage on the gate-source (Vgs), node 1 SMUA
performs a voltage
--sweep on the drain-source Vds) from start to stop in a user-defined number of steps, and
node 2 SMUA is
--used to bias the substrate (Vsb). Node 1 SMUB then increments to next bias value and
continues to stop
--value.
--Returns measured Vgs, Vds, Vsb, and Id values.
--Global variables
local l_vrange = 40 -
local l_icmpl = 100E-3 -
--Shared local variables
local l_nplc = 1 --Integration rate of measurement
--Local sweep variables
local l_vgsstart = vgsstart --Gate-source sweep start voltage
local l_vgsstop = vgsstop --Gate-source sweep stop voltage
local l_vgssteps = vgssteps --Number of steps in sweep
local l_vdsstart = vdsstart --Drain-source sweep start voltage
local l_vdsstop = vdsstop --Drain-source sweep stop voltage
local l_vdssteps = vdssteps --Number of steps in sweep
local l_vsbsource = vsbsource --Substrate bias value
--Default values and level check
if (l_vgsstart == nil) then --Use default value
l_vgsstart = 0
end --if
if (l_vgsstart > 10) then --Coerce value
l_vgsstart = 10
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end --if
if (l_vgsstop == nil) then --Use default value
l_vgsstop = 10
end --if
if (l_vgsstop > 10) then --Coerce value
l_vgsstop = 10
end --if
if (l_vgssteps == nil) then --Use default value
l_vgssteps = 5
end --if
if (l_vgssteps > 100) then --Coerce value
l_vgssteps = 100
end --if
local l_vgsstep = (l_vgsstop - l_vgsstart)/ (l_vgssteps - 1) --Vgs step size
local l_vgssource_val = l_vgsstart --Source value during sweep
local l_vgs_iteration = 1 --Iteration variable
if (l_vdsstart == nil) then --Use default value
l_vdsstart = 0
end --if
if (l_vdsstart > 10) then --Coerce value
l_vdsstart = 10
end --if
if (l_vdsstop == nil) then --Use default value
l_vdsstop = 10
end --if
if (l_vdsstop > 40) then --Coerce value
l_vdsstop = 40
end --if
if (l_vdssteps == nil) then --Use default value
l_vdssteps = 100
end --if
if (l_vdssteps > 2E+2) then --Coerce value
l_vdssteps = 2E+2
end --if
local l_vdsstep = (l_vdsstop - l_vdsstart)/ (l_vdssteps - 1) --Voltage step size
local l_vdssource_val = l_vdsstart --Source value during sweep
local l_vds_iteration = 1 --Iteration variable
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if (l_vsbsource == nil) then --Use default value
l_vsbsource = -1
end --if
if (l_vsbsource > 0) then --Coerce value
l_vsbsource = -l_vsbsource
end --if
if (l_vsbsource < -40) then --Coerce value
l_vsbsource = -40
end --if
--Data tables
local l_vgs_data = {} --Create data table for sourced gate-source voltage
local l_vds_data = {} --Create data table for drain-source voltage
local l_id_data = {} --Create data table for drain-source measured current
node[1].smua.reset() --Reset SMU
node[1].smub.reset() --Reset SMU
node[2].smua.reset() --Reset SMU
errorqueue.clear() --Clear the error queue
--Configure Drain-Source (node [1] SMUA) source and measure settings
node[1].smua.source.func = node[1].smua.OUTPUT_DCVOLTS
node[1].smua.source.autorangev = node[1].smua.AUTORANGE_ON --Enable source
autorange
node[1].smua.source.levelv = 0
node[1].smua.source.limiti = l_icmpl
node[1].smua.measure.autorangei = node[1].smua.AUTORANGE_ON --Enable measure
autorange
node[1].smua.measure.autozero = node[1].smua.AUTOZERO_AUTO
node[1].smua.measure.nplc = l_nplc --Measurement integration rate
node[1].smua.source.output = node[1].smua.OUTPUT_ON --Enable Output
--Configure Gate-Source (node [1] SMUB) source and measure settings
node[1].smub.source.func = node[1].smub.OUTPUT_DCVOLTS
node[1].smub.source.autorangev = node[1].smub.AUTORANGE_ON --Enable source
autorange
node[1].smub.source.levelv = 0
node[1].smub.source.limiti = l_icmpl
node[1].smub.measure.autorangei = node[1].smub.AUTORANGE_ON --Enable measure
autorange
node[1].smub.measure.autozero = node[1].smub.AUTOZERO_AUTO
node[1].smub.measure.nplc = l_nplc --Measurement integration rate
node[1].smub.source.output = node[1].smub.OUTPUT_ON --Enable Output
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--Configure Substrate (node [2] SMUA) source and measure settings
node[2].smua.source.func = node[2].smua.OUTPUT_DCVOLTS
node[2].smua.source.autorangev = node[2].smua.AUTORANGE_ON --Enable source
autorange
node[2].smua.source.levelv = 0
node[2].smua.source.limiti = l_icmpl
node[2].smua.measure.autorangei = node[2].smua.AUTORANGE_ON --Enable measure
autorange
node[2].smua.measure.autozero = node[2].smua.AUTOZERO_AUTO
node[2].smua.measure.nplc = l_nplc --Measurement integration rate
node[2].smua.source.output = node[2].smua.OUTPUT_ON --Enable Output
--Enable Substrate Bias (node [2] SMUA)
node[2].smua.source.levelv = l_vsbsource
--Execute sweep
for l_vgs_iteration = 1, l_vgssteps do
node[1].smub.source.levelv = l_vgssource_val
l_vds_data[l_vgs_iteration] = {} --Create new row in table
l_id_data[l_vgs_iteration] = {} --Create new row in table
l_vgs_data[l_vgs_iteration] = node[1].smub.measure.v() --Measure gate-source
voltage
for l_vds_iteration = 1,l_vdssteps do
if (l_vds_iteration == 1) then --Intialize start source value
l_vdssource_val = l_vdsstart
end --if
--delay(1)
l_vds_data[l_vgs_iteration][l_vds_iteration] = node[1].smua.
measure.v()
--Measure sourced voltage
l_id_data[l_vgs_iteration][l_vds_iteration] = node[1].smua.measure.i()
--Measure current
l_vdssource_val = l_vdssource_val + l_vdsstep --Calculate new source
value
if (l_vds_iteration == l_vdssteps) then --Reinitialize voltage value
after last
--iteration
l_vdssource_val = l_vdsstart
end --if
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node[1].smua.source.levelv = l_vdssource_val --Increment source
end --for
l_vgssource_val = l_vgssource_val + l_vgsstep --Calculate new source value
end--for
node[1].smua.source.output = node[1].smua.OUTPUT_OFF --Disable output
node[1].smub.source.output = node[1].smub.OUTPUT_OFF --Disable output
node[2].smua.source.output = node[2].smua.OUTPUT_OFF --Disable output
node[1].smua.source.levelv = 0 --Return source to bias level
node[1].smub.source.leveli = 0 --Return source to bias level
node[2].smua.source.levelv = 0 --Return source to bias level
Print_Data(l_vgssteps,l_vdssteps, l_vds_data, l_id_data, l_vgs_data, l_vsbsource)
end--function FET_Comm_Source_Vsb()
function Print_Data(vgssteps,vdssteps, vds_data,id_data, vgs_data, vsbsource)
--Print Data to output queue
--Local Variables
local l_vgssteps = vgssteps
local l_vdssteps = vdssteps
local l_vgs_iteration = 1 --Iteration variable
local l_vds_iteration = 1 --Iteration variable
local l_vds_data = vds_data
local l_id_data = id_data
local l_vgs_data = vgs_data
local l_vsbsource = vsbsource
for l_vgs_iteration = 1, l_vgssteps do
print(“”)
print(“Substrate Bias (V)”, l_vsbsource)
print(“Gate-source Bias (V)”, l_vgs_data[l_vgs_iteration])
print(“Drain-source Voltage (V)”,”Drain-source Current (A)”)
for l_vds_iteration = 1, l_vdssteps do
print(l_vds_data[l_vgs_iteration][l_vds_iteration], l_id_data[l_vgs_
iteration][l_vds_iteration])
end --for
end --for
end --function Print_Data()
--FET_Comm_Source_Vsb()
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Program 14. Common-Emitter Characteristics with Substrate Bias
--[[
BJT_Comm_Emit_Vsb(): USES TABLES
This program applies a bias to the base of a BJT (IB), a bias to the substrate (VSB), and
sweeps voltage on the collector/emitter (VCE).
The VCE, IB, and IC are then printed.
Required equipment:
(1) Dual-channel Keithley Series 2600 System SourceMeter instrument
(1) Keithley Model 2636 System Sourcemeter instrument (Required for low current
measurement)
(1) Crossover Ethernet Cable
(1) 2N5089 NPN Transistor or equivalent with substrate bias
- Connect the single-channel SourceMeter instrument to the dual-channel master using a
crossover Ethernet cable.
- Connect the test fixture to both units using appropriate cables.
- Turn on the SourceMeter instruments and allow the unit to warm up for two hours for
rated accuracy.
Configure the TSP-Link communications for each instrument:
Slave: A single-channel instrument such as the Model 2601, 2611, or 2635.
1. Press the MENU key to access MAIN MENU.
2. Select the COMMUNICATION menu. (Skip this step if the Series 2600 instruments
used have firmware Revision 1.4.0 or later installed.)
3. Select the TSPLINK_CFG menu. (If the Series 2600 instruments used have firmware
Revision 1.4.0 or later installed, the menu name should be TSPLINK.)
4. Select the NODE menu.
5. Set the NODE number to 2 and press ENTER.
Master: A dual-channel instrument such as the Model 2602, 2612, or 2636.
1. Press the MENU key to access MAIN MENU.
2. Select the COMMUNICATION menu. (Skip this step if the Series 2600 instruments
used have firmware Revision 1.4.0 or later installed.)
3. Select the TSPLINK_CFG menu. (If the Series 2600 instruments used have firmware
Revision 1.4.0 or later installed, the menu name should be TSPLINK.)
4. Select the NODE menu.
5. Set the NODE number to 1 for the Master and press ENTER.
6. Select the TSPLINK_CFG menu. (If the Series 2600 instruments used have firmware
Revision 1.4.0 or later installed, the menu name should be TSPLINK.)
7. Select the RESET to initialize the TSP-Link.
Running this script creates functions that can be used to measure the common emitter
characteristics of transistors. The default values are for an NPN transistor type 2N5089.
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The functions created are:
1. BJT_Comm_Emit_Vsb(istart, istop, isteps, vstart, vstop, vsteps,vsbsource)
--Default values istart = 10uA, istop = 50uA, isteps = 5, vstart = 0V, vstop = 10V,
--vsteps =100,vsbsource = 1V
2. Print_Data(isteps,vsteps, ce_volt,ce_curr, base_curr)
See detailed information listed in individual functions.
1) From Test Script Builder
- At the TSP> prompt in the Instrument Control Panel, type BJT_Comm_Emit_Vsb()
2) From an external program
- Send the entire program text as a string using standard GPIB Write calls.
Rev1: JAC 7.23.2007
]]--
------------------ Keithley TSP Function -----------------function BJT_Comm_Emit_Vsb(istart, istop, isteps, vstart, vstop, vsteps, vsbsource)
--Configure node 1 SMUB to source a --bias current on the base and node 1 SMUA performs a
voltage sweep on the Collector//Emitter from start to stop in a --user-defined number of
steps. --Node 2 SMUA delivers a user-defined voltage bias to the substrate. Node 1 SMUB then
increments to next bias value
--and continues to stop value. --Returns measured voltage and current
values.
--Global variables
local l_irange = 100E-6 --Base current source range
local l_vcmpl = 1 --Base source compliance
local l_vrange = 40 --Collector-emitter voltage source range
local l_icmpl = 100E-3 --Collector-emitter source compliance
local l_vsbsource = vsbsource --Substrate bias value
--Shared local variables
local l_nplc = 1 --Integration rate of measurement
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--Local sweep variables
local l_istart = istart --Base sweep start current
local l_istop = istop --Base sweep stop current
local l_isteps = isteps --Number of steps in sweep
local l_vstart = vstart --Collector-emitter sweep start voltage
Appendix A
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local l_vstop = vstop --Collector-emitter sweep stop voltage
local l_vsteps = vsteps --Number of steps in sweep
--Default values and level check
if (l_istart == nil) then --Use default value
l_istart = 10E-6
end --if
if (l_istart > 100E-6) then --Coerce value
l_istart = 100E-6
end --if
if (l_istop == nil) then --Use default value
l_istop = 50E-6
end --if
if (l_istop > 500E-6) then --Coerce value
l_istop = 500E-6
end --if
if (l_isteps == nil) then --Use default value
l_isteps = 5
end --if
if (l_isteps > 100) then --Coerce value
l_isteps = 100
end --if
local l_istep = (l_istop - l_istart)/ (l_isteps - 1) --Current step size
local l_isource_val = l_istart --Source value during sweep
local l_i = 1 --Iteration variable
if (l_vstart == nil) then --Use default value
l_vstart = 0
end --if
if (l_vstart > 100E-3) then --Coerce value
l_vstart = 100E-3
end --if
if (l_vstop == nil) then --Use default value
l_vstop = 10
end --if
if (l_vstop > 40) then --Coerce value
l_vstop = 40
end --if
if (l_vsteps == nil) then --Use default value
l_vsteps = 100
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end --if
if (l_vsteps > 2E+2) then --Coerce value
l_vsteps = 2E+2
end --if
local l_vstep = (l_vstop - l_vstart)/ (l_vsteps - 1) --Voltage step size
local l_vsource_val = l_vstart --Source value during sweep
local l_v = 1 --Iteration variable
if (l_vsbsource == nil) then --Use default value
l_vsbsource = 1
end --if
if (l_vsbsource > 40) then --Coerce value
l_vsbsource = 40
end --if
--Data tables
local l_base_curr = {} --Create data table for sourced current
local l_ce_volt = {} --Create data table for collector-emitter measured voltage
local l_ce_curr = {} --Create data table for collector-emitter measured current
node[1].smua.reset() --Reset SMU
node[1].smub.reset() --Reset SMU
node[2].smua.reset() --Reset SMU
errorqueue.clear() --Clear the error queue
--Configure Collector/Emitter (Node 1 SMUA) source and measure settings
node[1].smua.source.func = node[1].smua.OUTPUT_DCVOLTS
node[1].smua.source.autorangev = node[1].smua.AUTORANGE_ON --Enable source
autorange
node[1].smua.source.levelv = 0
node[1].smua.source.limiti = l_icmpl
node[1].smua.measure.autorangei = node[1].smua.AUTORANGE_ON --Enable measure
autorange
node[1].smua.measure.autozero = node[1].smua.AUTOZERO_AUTO
node[1].smua.measure.nplc = l_nplc --Measurement integration rate
node[1].smua.source.output = node[1].smua.OUTPUT_ON --Enable Output
--Configure Base (Node 1 SMUB) source and measure settings
node[1].smub.source.func = node[1].smub.OUTPUT_DCAMPS
node[1].smub.source.autorangei = node[1].smub.AUTORANGE_ON --Enable source
autorange
node[1].smub.source.leveli = 0
node[1].smub.source.limitv = l_vcmpl
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node[1].smub.measure.autorangev = node[1].smub.AUTORANGE_ON --Enable measure
autorange
node[1].smub.measure.autozero = node[1].smub.AUTOZERO_AUTO
node[1].smub.measure.nplc = l_nplc --Measurement integration rate
node[1].smub.source.output = node[1].smub.OUTPUT_ON --Enable Output
--Configure Substrate Bias (Node 2 SMUA) source settings
node[2].smua.source.func = node[2].smua.OUTPUT_DCVOLTS
node[2].smua.source.autorangev = node[2].smua.AUTORANGE_ON --Enable source
autorange
node[2].smua.source.levelv = 0
node[2].smua.source.limiti = l_icmpl
node[2].smua.measure.autorangei = node[2].smua.AUTORANGE_ON --Enable measure
autorange
node[2].smua.measure.autozero = node[2].smua.AUTOZERO_AUTO
node[2].smua.measure.nplc = l_nplc --Measurement integration rate
node[2].smua.source.output = node[2].smua.OUTPUT_ON --Enable Output
--Execute sweep
for l_i = 1, l_isteps do
node[2].smua.source.levelv = l_vsbsource
node[1].smub.source.leveli = l_isource_val
l_ce_volt[l_i] = {} --Create new row in table
l_ce_curr[l_i] = {} --Create new row in table
l_base_curr[l_i] = node[1].smub.measure.i() --Measure base current
for l_v = 1,l_vsteps do
if (l_v == 1) then --Intialize start source value
l_vsource_val = l_vstart
end --if
--delay(1)
l_ce_volt[l_i][l_v] = node[1].smua.measure.v() --Measure sourced
voltage
l_ce_curr[l_i][l_v] = node[1].smua.measure.i() --Measure current
l_vsource_val = l_vsource_val + l_vstep --Calculate new source value
if (l_v == l_vsteps) then --Reinitialize voltage value after last
iteration
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l_vsource_val = l_vstart
end --if
node[1].smua.source.levelv = l_vsource_val --Increment source
end --for
l_isource_val = l_isource_val + l_istep --Calculate new source value
end--for
node[1].smua.source.output = node[1].smua.OUTPUT_OFF --Disable output
node[1].smub.source.output = node[1].smub.OUTPUT_OFF --Disable output
node[2].smua.source.output = node[2].smua.OUTPUT_OFF --Disable output
node[1].smua.source.levelv = 0 --Return source to bias level
node[1].smub.source.leveli = 0 --Return source to bias level
node[2].smua.source.levelv = 0 --Return source to bias level
Print_Data(l_isteps,l_vsteps, l_ce_volt, l_ce_curr, l_base_curr,l_vsbsource)
end--function BJT_Comm_Emit()
function Print_Data(isteps,vsteps, ce_volt,ce_curr, base_curr, vsbsource)
--Print Data to output queue
--Local Variables
local l_isteps = isteps
local l_vsteps = vsteps
local l_i = 1 --Iteration variable
local l_v = 1 --Iteration variable
local l_ce_volt = ce_volt
local l_ce_curr = ce_curr
local l_base_curr = base_curr
local l_vsbsource = vsbsource
for l_i = 1, l_isteps do
print(“”)
print(“Base Current Bias (A)”, l_base_curr[l_i])
print(“Substrate Bias (V)”, l_vsbsource)
print(“Emitter Voltage (V)”,”Emitter Current (A)”)
for l_v = 1, l_vsteps do
print(l_ce_volt[l_i][l_v], l_ce_curr[l_i][l_v])
end --for
end --for
end --function Print_Data()
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--BJT_Comm_Emit_Vsb()
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Section 6. High Power Tests
Program 15. High Current with Voltage Measurement
--[[
KI2602Example_High_Current.tsp
This program is intended to perform the following:
1. Set up both SMUs of a Model 2602 for current bias and measure voltage on specific
intervals.
2. Deliver up to 2A @ 40V (1A @ 40V per SMU) by wiring each SMU in parallel
Wiring: SMUA Hi to SMUB Hi, SMUA Lo to SMUB Lo
WARNING: If either SMU reaches a compliance state, the instrument, device, or both
could be damaged.
System Requirements: 260x Firmware version: 1.0.2 or newer
Rev1: JAC 3.21.2006
Rev2: JAC 10.15.2007
-Change l_sourcei value to sourcei/2. Desired current value at DUT is now
programmed.
--]]
function RunHighCurrent(sourcei, points)
local l_sourcei = sourcei/2 --Local variable for Source Current Value
local l_points = points --Local variable for number of points to sample
local l_cmpl = 40 --compliance must not be reached!
--Configure display
display.clear()
display.screen = display.SMUA_SMUB
display.smua.measure.func = display.MEASURE_DCVOLTS
display.smub.measure.func = display.MEASURE_DCVOLTS
-- Configure source and measure settings.
smua.source.output = smua.OUTPUT_OFF --Disable Output
smub.source.output = smub.OUTPUT_OFF --Disable Output
smua.source.func = smua.OUTPUT_DCAMPS --Set Output function
smub.source.func = smub.OUTPUT_DCAMPS --Set Output function
smua.source.leveli = 0 --Set output level
smub.source.leveli = 0 --Set output level
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smua.source.rangei = l_sourcei --Set output level
smub.source.rangei = l_sourcei --Set output level
smua.source.limitv = l_cmpl --Set compliance level
smub.source.limitv = l_cmpl --Set compliance level
smua.measure.nplc = 1 --Set measurement aperture
smub.measure.nplc = 1 --Set measurement aperture
smua.measure.autozero = smua.AUTOZERO_AUTO --Set Autozero mode
smub.measure.autozero = smub.AUTOZERO_AUTO --Set Autozero mode
-- Setup SMUA buffer to store all the result(s) in and start testing.
smua.nvbuffer1.clear() --Clear Nonvolatile buffer
smua.nvbuffer1.appendmode = 0 --Append buffer? 0 = No, 1 = Yes
smua.nvbuffer1.collecttimestamps = 0 --Collect Timestamps? 0 = No, 1 = Yes
smua.nvbuffer1.collectsourcevalues = 0 --Collect Source Values? 0 = No, 1 = Yes
smua.source.output = smua.OUTPUT_ON --Enable outputs
smub.source.output = smua.OUTPUT_ON --Enable outputs
smua.source.leveli = l_sourcei
smub.source.leveli = l_sourcei
-- Program source to level.
-- Program source to level.
smua.measure.count = l_points --Number of points to collect
smua.measure.v(smua.nvbuffer1)
-- Measure voltage and store in reading buffer.
smua.source.output = smua.OUTPUT_OFF
smub.source.output = smub.OUTPUT_OFF
-- Update the front panel display and restore modified settings.
smua.source.leveli = 0
smub.source.leveli = 0
printbuffer(1,l_points,smua.nvbuffer1)
end --function RunHighCurrent(sourcei, points)
--RunHighCurrent(1, 10)
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Program 16. High Voltage with Current Measurement
--[[
KI2602Example_High_Voltage.tsp
This program is intended to perform the following:
1. Set up both SMUs of a Model 2602 for voltage bias and measure current on specific
intervals.
2. Deliver up to 80V @ 1A (40V @ 1A per SMU) by wiring each SMU Voltage Source in
series.
Wiring: SMUA Lo to SMUB Hi, SMUA Hi to DUT, SMUB Lo to DUT
WARNING: If either SMU reaches a compliance state, the instrument, device, or both
could be damaged.
System Requirements: 260x Firmware version: 1.0.2 or newer
Rev1: JAC 3.21.2006
Rev2: JAC 10.15.2007
-Change l_sourcev value to sourcev/2. Desired voltage value at DUT is now
programmed.
--]]
function RunHighVoltage(sourcev, points)
local l_sourcev = sourcev/2 --Local variable for Source Voltage Value
local l_points = points --Local variable for number of points to sample
local l_cmpl = 1 --compliance
--Configure display
display.clear()
display.screen = display.SMUA_SMUB
display.smua.measure.func = display.MEASURE_DCAMPS
display.smub.measure.func = display.MEASURE_DCAMPS
-- Configure source and measure settings.
smua.source.output = smua.OUTPUT_OFF --Disable Output
smub.source.output = smub.OUTPUT_OFF --Disable Output
smua.source.func = smua.OUTPUT_DCVOLTS --Set Output function
smub.source.func = smub.OUTPUT_DCVOLTS --Set Output function
smua.source.levelv = 0 --Set output level
smub.source.levelv = 0 --Set output level
smua.source.rangev = l_sourcev --Set output level
A-80
Appendix A
Scripts
smub.source.rangev = l_sourcev --Set output level
smua.source.limiti = l_cmpl --Set compliance level
smub.source.limiti = l_cmpl --Set compliance level
smua.measure.nplc = 1 --Set measurement aperture
smub.measure.nplc = 1 --Set measurement aperture
smua.measure.autozero = smua.AUTOZERO_AUTO --Set Autozero mode
smub.measure.autozero = smub.AUTOZERO_AUTO --Set Autozero mode
-- Setup SMUA buffer to store all the result(s) in and start testing.
smua.nvbuffer1.clear() --Clear Nonvolatile buffer
smua.nvbuffer1.appendmode = 0 --Append buffer? 0 = No, 1 = Yes
smua.nvbuffer1.collecttimestamps = 0 --Collect Timestamps? 0 = No, 1 = Yes
smua.nvbuffer1.collectsourcevalues = 0 --Collect Source Values? 0 = No, 1 = Yes
smua.source.output = smua.OUTPUT_ON --Enable outputs
smub.source.output = smua.OUTPUT_ON --Enable outputs
smua.source.levelv = l_sourcev
smub.source.levelv = l_sourcev
-- Program source to level.
-- Program source to level.
smua.measure.count = l_points --Number of points to collect
smua.measure.i(smua.nvbuffer1)
-- Measure current and store in reading buffer.
smua.source.output = smua.OUTPUT_OFF
smub.source.output = smub.OUTPUT_OFF
-- Update the front panel display and restore modified settings.
smua.source.levelv = 0
smub.source.levelv = 0
printbuffer(1,l_points,smua.nvbuffer1)
end --function RunHighVoltage(sourcev, points)
--RunHighVoltage(40, 10)
A-81
Specifications are subject to change without notice.
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© Copyright 2009 Keithley Instruments, Inc.
Printed in the U.S.A.
No. 2911
12.03.09
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