Cellular automata for device simulation-concepts and applications

We present a discussion of various concepts of cellular automata for semiconductor transport in the context of device simulation. A newly developed transformation for the kinetic terms of the Boltzmann equation into deterministic transition rules are found to be superior to probabilistic rules, allowing a complete suppression of statistical errors without any loss in numerical performance. To take advantage of the high speed of the resulting Cellular Automaton, a fast and flexible multigrid-solver for the Poisson equation has been developed. This enables us to study also fluctuations of transport quantities, which determine the high frequency noise behavior of MOSFETs, within the Cellular Automata approach. The reliability of the new CA approach for nanostructured devices is demonstrated by a study of gate length influence onto the drain current characteristics of a novel vertically grown MOSFET.