Self-consistent numerical model and optimization of two-dimensional electron gases for AlGaN/GaN HEMT

AlGaN/GaN HEMTs, also referred to MODFETs, have been a subject of intense recent investigation and have emerged as attractive candidates for high voltage, high-power operation at microwave frequencies for its high peak electron velocity, saturation velocity, saturation velocity, thermal stability and breakdown fields properties. In this paper, we take account of spontaneous and piezoelectric polarization effect at the hetero-interface in AlGaN/GaN HEMT device and one-dimensional Poisson-Schrodinger equations using nonuniform mesh are solved self-consistently, from which the AlGaN/GaN heterostructure conduction band and the 2DEG density are investigated. The dependences of 2DEG characteristics on the Al mole fraction, the thickness of each layer, the donor concentration and the gate voltage are investigated through simulation, respectively. The influence of spacer layer width on the 2DEG density is calculated for the first time.