Hi all!

I have a problem with Verilog-A modeling in Spectre 6.x.

I use BSIM3 model implemented in Verilog-A by Geoffrey Coram (the file was available at Silvaco and then - at Simucad site some time ago). See attached file. I have successfully used it with Spectre 5.1.41.

My "standard" task is to simulate MOSFET DC characteristics. Transistor is taken from PDK. In model file there is a subckt which uses the instance described as Verilog-A module (using "ahdl_include"). All SPICE parameters are described as instance parameters (instance inside subcircuit):

inline subckt nmos_tn (d g s b)
parameters w=1E-7 l=1E-7 PAR=1 as=0 ad=0 ps=0 pd=0 nrd=0 nrs=0
...
nmos_tn (d g s b) bsim3mos W=w L=l AD=ad AS=as PD=pd PS=ps ...
+ TYPE=1
...
+ U0=0.035597185
...
ends nmos_tn

, where "bsim3mos" is verilog-A module.

But when I try to simulate this with Spectre 6.0 or even with Spectre 6.2 some Verilog-A module parameters are not recognized as instance parameters by simulator (and some parameters, e.g. W, L, TYPE and TOX are still recognized, but U0 isn't). Warning message is generated:

"U0 is not a valid parameter for an instance bsim3mos. Ignored"

And then characteristics with default values (defined in Verilog-A module) of parameters are simulated.

Could you help me to solve this problem or just give an advice how should I search the possible reasons?

P.S. By the way, does anybody know why the files with Verilog-A MOSFET models are not available now?

Hi,

I am working on low temperature MOSFET modeling, for which verilog-a implementation of BSIM3 model is required. I could not locate it at the SILVACO site or from any other source. If someone who has the code could share it, that would have been really helpful.

cryogenic, I've answered via e-mail.

I've modified the "original" file from Silvaco a little bit to make it compatible with Spectre simulator. This modified file is attached in the first post.