Physical Models for Semiconductor Device Simulation

Device simulation has two main purposes: to understand and to depict the physical processes in the interior of a device, and to make reliable predictions of the behavior of the next device generation. Towards these goals, the quality of the implemented physical models is decisive, forcing heuristic t models to be replaced by \\rst-principle"-based models. Since transport schemes using moments of the Boltzmann equation are still dominant within the simulation community, the challenge in developing models is given by a clever combination of sound physics with functional simplicity. The extent to which this has been possible will be demonstrated by means of two examples: band gap narrowing and band-to-band tunneling. We point out the limitations set by the poor knowledge of certain parameters, by the breakdown of common approximations, and by unresolved principle problems.