S530 Parametric Test System Test Subroutine Library User's Manual
Section 3: Test subroutine library reference
S530-907-01 Rev. A / September 2015
3-77
The procedural differences are:
A binary search on V
GS
is done to find I
DS
(
vstart
)
Calculate sweep limits: The
vlow
parameter =
vstart
The
vhigh
parameter =
vstart
+
npts
*
vstep
Sweep the I
DS
-V
GS
data set
Perform a sliding five-point linear least-squares (LLSQ) analysis (as in the
vtext
subroutine)
If a zero or negative substrate pin is specified, the substrate is left floating. If the pin number is
greater than 0 and V
BS
is less than 0.9 mV, the substrate is grounded. In all other cases, it is
connected and forced.
The
npts
parameter must be greater than 5. If a value less than 5 is used, the subroutine uses 5
points by default.
V/I polarities
The polarities of V
DS
and I
THR
are determined by the device type.
The
vstep
parameter is 10 mV to 100 mV. This depends on the
vlow
and
vhigh
parameters. For
an N-channel, if
vlow
= 0.0 and
vhigh
= 2.0,
vstep
should be positive.
Source-measure units (SMUs)
SMU1: Forces
vds
, default current limit, measures I
DS
SMU2: Searches V
GS
, default current limit
SMU3: Forces
vbs
, default current limit
Example
result = vtext2(d, g, s, sub, type, vlow, vhigh, vds, vbs, ithr, vstep, npts,
&slope, &kflag)
Schematic