neoflash wrote on Jan 29th, 2011, 3:01pm:Thanks for the heads up. I just want to get some quick answer before I get into sleep last night.
I did some simple google search and yes, this effect is included in the bsim model.
What do you mean neoflash? Sure! impact ionization can be modelled using the BSIM4 model, but only if the foundry has bothered to measure the relevant parameters and keyed them into the model file you are using. You can check your model file for parameters: alpha0, alpha1 and beta0 (For a description, do spectre -help bsim4, and for the entire expression for impact ionization current, check the BSIM4 manual). Usually, the alpha parameters are set to zero when the effect is not characterized by the foundry. Of course, the foundry could also have dummy non-zero numbers which are not accurate, or do not show the true variation etc.
So, you can either look through all the details if this effect really matters to you, or else engineer your way around it. There are many ways of doing that.
Vivek