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
Dear Nelson,
Find the find the transconductance. The voltage is the voltage at which the trasconductance is maximum. This is one way of finding threshold voltage.
Otherwise, you can ask like this " At what drain current, the threshold voltage is measured? Right now I don't know at what drain current it is measured. You please compare drain current of standard article and find how they taking vth.
- Badges
- Science topic