This is an example Verilog-A model of a level 1 model - which is not really going to be applicable to any modern technologies (it's an early SPICE model). It's there as an illustration of how device models can be implemented in Verilog-A.

You would be far better off using one of the built-in models in spectre or AMS Designer (e.g. bsim3v3, bsim4 etc). In practice you'll use a model file which sets the parameters for these models for the technology you're using - you wouldn't just make something up.

Or, if you want an illustration, download the Cadence "GPDK" (Generic Process Design Kit) from http://pdk.cadence.com - this gives example models for a typical process - if my memory serves, 0.18u and 90nm examples are available. This is not tied to any foundry - just for illustration purposes.

If you're using a particular technology, get the design kit from the supplier of that technology, and use the models provided.

Regards,

Andrew.