Physics-based Analytical Modeling of p-GaN/AlGaN/GaN HEMTs

In this paper, a physics based analytical model is reported for potential variations at the various interfaces of pGaN cap AlGaN/GaN HEMT. This model uses solution of the Poisson’s equation self consistently for the calculation of potential drop at different regions. The 2D-density of states and the FermiDirac (FD) distribution are used to calculate the charge densities at various interfaces. The suggested model fits the TCAD and experimental data for the p-GaN cap HEMT and is explicit in nature providing physical insight of voltage drops at each layer and the correlation with the device parameters. An analysis is presented regarding the effect of out-diffused Mg dopants, polarization charges at various layers as well as the doping concentration of acceptor ions in p-GaN cap layer.