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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 incre-
mented and the drain-source sweep is re-run .
11 .
Once the gate-source sweep has been completed, the data
(V
, V
, V
, and I
) will be presented in the Instrument
SB
GS
DS
D
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 V
, is configured as follows:
GS
•
Source V
•
1mA compliance, autorange
•
Local sense
•
: 0V
vgsstart
•
: 10V
vgsstop
•
: 5
vgssteps
Next, Node 1 SMUA, which sweeps V
to operate in the following manner:
•
Source V
•
Local sensing
•
100mA compliance, autorange measure
•
1 NPLC Line cycle integration
•
: 0V
vdsstart
•
: 10V
vdsstop
•
: 100
vdssteps
Finally, Node 2 SMUA, which provides substrate bias, is pro-
grammed as follows:
•
Source V
•
Local sensing
•
10mA compliance, autorange measure
Both instruments are returned to default conditions; the sources
are zeroed and enabled . The substrate bias (V
(V
) are applied and the program enters the main program loop
GS
to perform five I
vs . V
sweeps, one for each of five V
D
DS
Node 1 SMUA then cycles through its sweep list, setting V
and measures I
, is set up
DS
D
) and gate-source
SB
values .
GS
to the
DS
required values, and measuring I
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 .
5.3.10 Modifying Program 13
For different sweeps, the V
GS
V
stop, and V
steps values can be changed as required . For
DS
DS
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 I
, while Node 1 SMUA sweeps V
B
measures I
. Node 2 SMUA applies the substrate bias (V
C
device under test .
5.4.2 example Program 14: Common-
emitter Characteristics with a
Substrate Bias
Program 14 demonstrates common-emitter characteristic test pro-
gramming with substrate bias . Proceed as follows:
1 .
With the power off, connect the dual-channel System Source-
Meter instrument to the computer's IEEE-488 interface . Con-
nect 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 .
3 .
Turn on the instruments and allow the units to warm up for
two hours for rated accuracy .
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 .
SeCTIon 5
Using Substrate Bias
at each step along the way . The
D
start, V
stop, V
steps, V
GS
GS
DS
) to the
SB
start,
and
CE
5-7
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