Continue to Site

Welcome to

Welcome to our site! is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

How to know,calculate the Cox,mobility values from model files ?

Not open for further replies.


Newbie level 2
Jan 25, 2013
Reaction score
Trophy points
Activity points
I am designing and simulating an analog circuit using 45nm nmos,pmos . I am using model files from :
I need the mobility and Cox (gate oxide capacitance per unit area) values for designing of circuit.Can anyone help me how to
know,calculate the mobility and Cox values from model files.

I would suggest that you try to extract the Kp and Kn instead, you will probably also need the slope factor n. Try to extract Kp,Kn for different values of W/L and see how they vary. Perhaps you could use an average value of the results for the Kp,Kn

I would also be very reserved with the hand calculated results if you intend to use the quadratic equation for a MOS transistor in saturation or the exponent equation for a MOS in subtreshold. If not already you should have a look at gm/Id method with EKV model and similar approaches.


u0 in those model cards is the surface mobility (you
want to sanity-check units & so on, relative to your
simulator-of-choice's defaults).

toxe is your "electrical oxide thickness" as distinct
from optical / actual, it may include some poly depletion
or be fudged to get a right result. Anyway, this goes in
your C=E*E0*A/t calculation.

In both of these cases second-order related params
look to be populated and you'd have to dope out how
those might modify the declared basic param.

Reading the unpleasantly long and detailed BSIM model
docs would do you some good, if you wanted to know
what you're looking at.

thanks for the reply , i will try these

Not open for further replies.

Part and Inventory Search

Welcome to