threshold voltage question

[vhdl00]

i run hspice simulations recently, found that the threshold voltage is different for same device, i mean other than body effect, is there any other factors affect threshold voltage?

 

[holddreams]

in which case ?
do you use the same corner? that is ,typical typical corner?ff corner?
in different corner,the vth will change a little.

 

[sunking]

it depond on the voltage and current,too.

 

[hrkhari]

Hi:

I deep submicron process the Vth decreases due to the increase of Vds and this effect is known as drain induced barrier lowering (DIBL).

Rgds

 

[ambreesh]

Usually foundy specifies the vth depending on w and L of devices you are going to use.
If you go through the BSIM3v3 manual, you would find that the threshold voltage is a function of loads of other parameters.
And the value you would observe in the model file is for hand calculations when you do design.
A question what percentage variation did you observe.
Holberg in his book has mentioned on how one should characterise a mos device, kindly go through that, it would be great help to you.
Hope it helps.