Abstract
The author presents a systematic evaluation of transport properties of semiconducting submicron structures as predicted by computer simulations based on the Boltzmann equation. The influence of variations in the relaxation time of the collision process and the geometry of a model n+nn+-diode are studied. Both ballistic and nonballistic situations are considered and compared to approximating moment models. Already small ballistic effects, showing up as nonuniform features in the high velocity behaviour of the distribution function, cause considerable error in the moment model predictions for the I-V characteristics.