> At the research level, they have simulations based on real physics (not curve fits) that will determine the transistor properties quite accurately.
That's true, but that's why I restricted my statement to a "modern SPICE model". I said "modern" because the Level 1-2 FET models contain only parameters with known physical meaning. Subsequent levels improve accuracy, but some of the parameters they introduce do not have known physical meaning.
> A SPICE model is essentially (mostly) simple classical equations for a MOSFET, coupled with curve fits to fix Nth order effects. A lot of the curves are still based on physics knowledge, but parametrized to make it easy to fit the data.
I agree with that description, and that's the blend of theoretical understanding and empirical curve fitting that I was trying to capture with the phrase "semi-empirical". My point is that even for something as well-understood as a FET, we found that semi-empirical model to be more convenient for most practical purposes. As engineers we think that's fine (all models are wrong but some are useful, etc.), but pure mathematicians seem to find it unthinkable.
That's true, but that's why I restricted my statement to a "modern SPICE model". I said "modern" because the Level 1-2 FET models contain only parameters with known physical meaning. Subsequent levels improve accuracy, but some of the parameters they introduce do not have known physical meaning.
> A SPICE model is essentially (mostly) simple classical equations for a MOSFET, coupled with curve fits to fix Nth order effects. A lot of the curves are still based on physics knowledge, but parametrized to make it easy to fit the data.
I agree with that description, and that's the blend of theoretical understanding and empirical curve fitting that I was trying to capture with the phrase "semi-empirical". My point is that even for something as well-understood as a FET, we found that semi-empirical model to be more convenient for most practical purposes. As engineers we think that's fine (all models are wrong but some are useful, etc.), but pure mathematicians seem to find it unthinkable.