Section 7: Measuring I-V characteristics of FETs
Model 2450 Interactive SourceMeter® Instrument User's Manual
7-8
2450-900-01 Rev. A / June 2013
Using SCPI commands in a linear sweep to set up the test
In this example, the gate voltage steps from 2 V to 6 V in 1 V steps, the drain voltage sweeps from
0 V to 5 V in 51 steps, and the drain current is measured. Each of 51 readings and source values are
retrieved from
defbuffer1
and saved in the arrays
vds
and
ids
, respectively.
Commands are sent to either the sweeper (SMU 1) or the stepper (SMU 2). Commands for the
sweeper are shown with a light gray background, and commands for the stepper are shown with a
darker gray background. Each bulleted item in the Description column describes a single line of code
in the Commands column. The light-brown shaded code represents pseudocode that will vary
depending on the programming environment you use.
Send the following commands for this example application:
SMU 1,
SMU 2, or
pseudocode
Commands
Description
SMU 2
*RST
SENS:FUNC "CURR"
SENS:CURR:RANG:AUTO ON
ROUT:TERM REAR
SOUR:FUNC VOLT
SOUR:VOLT:RANG 20
•
Reset the instrument.
•
Set to measure current.
•
Set to measure with autorange enabled.
•
Set to use rear terminals.
•
Set to source voltage.
•
Set to 20 V source range.
SMU 1
*RST
SENS:FUNC "CURR"
SENS:CURR:RANG:AUTO ON
ROUT:TERM REAR
SOUR:FUNC VOLT
SOUR:VOLT:RANG 20
SOUR:VOLT:ILIM 1
SOUR:SWE:VOLT:LIN 0, 5, 51, 0.01
•
Reset the instrument.
•
Set to measure current.
•
Set to measure with autorange enabled.
•
Set to use the rear terminals.
•
Set to source voltage.
•
Set to the 20 V source range.
•
Set the source limit to 1 A.
•
Set up a linear sweep from 0 V to 5 V in 51
steps, with a delay of 10 ms.
SMU 2
OUTP ON
•
Turn on the output.
Pseudocode
vds = []
ids = []
for i=2, 5 do:
•
In whichever programming environment
you are using, create an empty array to
hold measured voltage values.
•
Create an empty array to hold measured
current values.
•
Set up a
for
loop from 2 to 5 (inclusive).
