Theoretical Study of The Charge Control in AlGaN/GaN HEMTs

This paper presents a simplified numerical model for the charge control in AlGaN/GaN high electron mobility transistor (HEMT). The model is based on solution of Poisson´s equation in the AlGaN layer, including the effect of spontaneous and piezoelectric polarizations. A non-linear formulation of the strain-induced polarization fields has been considered. The model results indicate a close agreement with other complicated models. Theoretical study of the effects of structural and processing parameters on the charge control has been presented. The examined parameters are: the AlGaN barrier layer thickness and doping, the spacer layer thickness, and the Al mole fraction x. Completely different effects for some parameters have been detected and explained