Vp1 - Keithley S530 User Manual

S530 Parametric Test System Test Subroutine Library User's Manual

vp1

This subroutine estimates the voltage at which the current flow between the source and drain is blocked
("pinched-off") for a metal-semiconductor field-effect transistor (MESFET) at a specified "pinch-off" current and
drain-source voltage (V
Usage
void vp1(int d, int g, int s, int sub, double ids, double vdlim, double vg1, double
vg2, double iglim, double *iflag, double *vp)
d
g
s
sub
ids
vdlim
vg1
vg2
iglim
iflag
Returns
Details
This subroutine is a variant of the vp subroutine. The trigger is set to the specified V
current (I
0 V gate-source voltage (V
increases as the device approaches the voltage at which the current flow between the source and
drain is blocked.
If a positive substrate pin is specified, the substrate is grounded. If a positive substrate pin is not
specified, the substrate is left floating.
A delay is incorporated into the vp1 subroutine; this delay is the calculated time required for stable
forcing of drain-source current (I
V/I polarities
vg1, vg2 - Ensures that polarity forward biases the gate-source diode. Starting voltage, vg1, must
allow the drain SMU to supply pinch-off current without exceeding the limit.
Source-measure units (SMUs)

SMU1: Forces drain-source current (ids), programmable voltage limit, trigger set to V

SMU2: Searches V
S530-907-01 Rev. A / September 2015
).
DS
Input The drain pin of the device
Input The gate pin of the device
Input The source pin of the device
Input The substrate pin of the device
Input
The forced drain current (I
Input The drain voltage target, in volts
Input
Start of the gate-source voltage (V
Input
End of the V
Input Gate current limit, in amperes
Output Return status flag:
0 = Normal completion
1 = Pinch-off voltage (V
2 = Device triggered on starting voltage
3 = Device triggered on ending voltage
Output
Measured V
) is forced on the drain. The gate voltage is then searched until the V
P
), the drain voltage is below the specified V
GS
DS
, programmable current limit
GS
), in amperes
P
search, in volts
GS
) is 0.0
P
P
) with the V voltage limit.
DS
Section 3: Test subroutine library reference
) search, in volts
GS
and pinch-off
DS
value is reached. At
DS
. As V is increased, V
DS GS DS
DS
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