Re: Extracting transistor characteristic parameter from BSIM 4 model
For my interest: Why do you need the parameters?
Isn't the requirement on gm and r0 given by the specification of your component or the impact that they cause on the output signal, or so? Based on that you will get a performance that you have to obtain and as indicated in the previous reply, you would - since the hand calculations do not really hold - iterate the currents/sizes until you reach the requirements.
Even if you find a u0,Cox and can calculate the requirements, there would still be significant variations over operating conditions, linearized region, and corners, where you would have to adapt a slightly different methodology.
(Maybe I'm stating the obvious, but yet...)