Influence of doping on the two-dimensional electron gas distribution in AlGaN/GaN heterostructure transistors

A study of two-dimensional electron gas distribution in AlGaN/GaN heterostr ucture field effect transistors is performed by solving the coupled Schrodi nger's and Poisson's equation self-consistently. Taking the piezoelectric e ffect into account, the two-dimensional electron gas concentration is calcu lated to be as high as 10(19) cm(-3). To gain an understanding on how the t wo-dimensional electron gas distribution is influenced by dopant concentrat ion in material, we observed the two-dimensional electron gas concentration and occupation of subbands versus doping level in GaN and in AlGaN layer. The results show that the two-dimensional electron gas concentration depend s much more strongly on the doping level in AlGaN than in GaN. And besides, the heavier doping in GaN should weaken the quantum confinement in the AlG aN/GaN heterointerface. (C) 2001 American Institute of Physics.