THE HIGH ELECTRON MOBILITY TRANSISTOR (HEMT) - PHYSICAL FUNDAMENTALS AND QUASI TWO-DIMENSIONAL (Q2D) SIMULATION

Abstract

Construction, function, and physical fundamentals of the high electron mobility transistor (HEMT) are shortly reviewed. It is the main feature of a semiconductor heterostructure of this type that a 2D electron gas occurs which demands a careful consideration of quantum size effects. For doing this with a moderate numerical expense, a very convenient method is proposed which is basically a modification of the well-known Thomas-Fermi approxi-mation for potentials with steps. By means of this method a quasi-2D simulation of the standard HEMT is carried out. First the electronic properties of the HEMT without a source-drain voltage are determined. Assuming a suitable semi-empirical mobility model, the current-voltage characteristics are calculated, too, without using any fitting parameters. The influence of geometrical and material parameters as well as of the temperature and doping on the electronic properties of the HEMT is discussed.