simon2
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Southampton, United Kingdom.
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Hi xwcwc1234, I can appreciate where perhaps one may be in a situation where you are stuck with the simulator of someone else's choice (which may be an older version of spectre-cadence) or perhaps have to support someone who does not use cadence tools (for example an external design house or foundry provider) which means that you maynot be able to go to the latest version of the Cadence tools.
The solution I use is to maintain a set of test-benches that re-run the process "playbacks" (published in the Foundry documentation) for each device. These test-benches use the same "test" circuit, but call different model files for (say) nmos or pmos or npn or a diode and will become over time a superset of all the processes you use (mine are now about 8 years old and cover some 20 processes). I maintain these for each tool-set/simulator we support, adding new tools and processes as they become available allowing us to verify model accuracy, parameter coverage, model robustness and so on.
Having built such a knowledge base, you will then be able to look at parameters such as those above and decide which matter to the application you are designing for - some such as those listed above may not, so comment them out in model file (remember to keep a backup of the originals just in case you completely break the model).
I would strongly recommend that you read a book such as "MOSFET Modeling and BSIM3 User's Guide" by Cheng and Hu, to get an idea of what these parameters do and if they matter to you. In time you will find that you can write sub-circuits that add these features if necessary, or even produce you own bespoke model files that emulate the behavior the "extra" parameters pertain to, even though the simulator does not directly model those parameters.
You will find after a while that you are only limited your ability rather than the tools - they just make the challenge interesting, the point being that you will have to start your design somewhere and the re-simulating the foundry playbacks in your simulator make an excellent starting point.
Cheers, SimonH.
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