If I use LTspice do I have to modify the SPICE models that I download from MOSIS?
The models I download from CMOSedu.com work great with LTspice but I want to try
some other technologies.
Yes, but you will have to change the Level = 49 to Level = 8 for the BSIM3 models you
download from MOSIS at: http://www.mosis.com/requests/test-data
For the BSIM4 models LTspice uses Level = 54 which is what MOSIS supplies so no
change is needed.
In any case I would download the models, draft a ring oscillator, and compare the
simulated oscillation frequency to the measured value reported by MOSIS in these files
to verify that the models are working correctly.