[SOLVED] how can i plot the VT-VSB characteristic of an NMOS

[prcken]

how can i plot the threshold voltage VTof the nmos versus the voltage bettwen source and bulk VSB with Hspice
VSB is negatively increased.
VT is defined at the piont when the current is at 1um
sweep the vin and vsb
i just can plot the I--Vin characteristic

how to wirte the netlist or should i use some function to plot??
*********************
the I versus Vin characteristic
*********************
m1 1 2 0 3 nch l=0.25u w=2.5u
R1 4 1 1K
vdd 4 0 2.5
vin 2 0 0
vsb 3 0 0
.lib 'E:\work\logic025.l' TT
.model nch nmos
.dc vin 0 2.5 0.1 sweep vsb 0 -2.5 -0.1
.probe i(m1)
.end

 

[Hughes]

* Vth vs VSB
m1 1 2 0 3 nch l=0.25u w=2.5u 
R1 4 1 1K 
vdd 4 0 2.5 
vin 2 0 0 
vsb 3 0 0 
.lib 'E:\work\logic025.l' TT 
.model nch nmos 
.dc vin 0 2.5 0.1 sweep vsb 0 -2.5 -0.1 
.probe i(m1) 
.meas dc vth find V(2) when I(m1) = 1u
.end

The .ms0 file will contain the vth-vsb data.
In awaves, set outer sweep variable vsb as the x-axis and plot measured parameter vth.