The Designer's Guide Community Forum

The Designer's Guide Community Forum
https://designers-guide.org/forum/YaBB.pl
Simulators >> Circuit Simulators >> breakdown voltage
https://designers-guide.org/forum/YaBB.pl?num=1125493024

Message started by aamar on Aug 31^st, 2005, 5:57am

Title: breakdown voltage
Post by aamar on Aug 31^st, 2005, 5:57am

Dear Sirs,

I am using a device model (subckt) which is including a MOS transistor, in my simulations I have to reach a voltages of about 30V on the gate source of the transistors, I receive a warning from Spectre telling that Vgs has exceeded the breakdown voltage of Vbox=30V.

only warning, no errors and at the end I get results for the simulation.

Are these simulation results true or not?

At the same time what is the effect of reaching these voltages on both DC and transient behav. of the transistor?

Is there any other technologies which can hold these 30V other than the High voltage models ?, it doesn't matter the process at the moment, bcz I am just simulating.

Thanks in advance.

aamar

Title: Re: breakdown voltage
Post by Geoffrey_Coram on Aug 31^st, 2005, 12:37pm

You may be getting a default value for Vbox; the documentation says

224 vbox=1e9*tox V Oxide breakdown voltage.

so if you have a tox of 30nm, you'd get Vbox=30. You should look in your model card to see if there is a value specified for Vbox, indicating that someone decided they had enough information to specify such a quantity.

If you're just simulating, you can (a) ignore the warning, since it's just a warning, or (b) add Vbox=10000 to the .model card.

-Geoffrey