I am trying to extract Threshold Voltage of MOSFET by using extraction.
extract name="vt" (xintercept(maxslope(curve(v."gate",abs(i."drain")))) + abs(ave(v."drain"))/2.0)
But, the Vgs intercepting point by using the maximum slope method is coming very small ( nearly ZERO). That's why I'm getting Vt=Vds/2.
On the other side if I use the CONSTANT DRAIN CURRENT METHOD, then the value is not found in the graph. If I forcefully change the drain current value then the new value is not again found for some other channel Length.
extract name="vt" x.val from curve (abs(v."gate"),abs(i."drain")) where y.val=1e-6
What is right procedure or method and how to solve this problem?
I have included the Id-Vgs graph. Saturation region is not shown due to smaller range of Vgs.
When I try to extract the threshold voltage, I'm getting only the Vds/2 part.
How do I correctly find Vt value?
Dear Mr. Nelson,
Adding to Aparna,
You can fit the transfer curve of the MOSFET in the saturation region by the equation:
ID= Kp W/2L { VGS-Vt)^2,
so, all what you need is to plot sqroot of ID versus VGS. Then you best fit it by a staight line extrapolating this staight line to the VGS axis cuts it in the thershold voltage Vt.
Best wishes
- Badges
- Science topic