Analytical Surface Charge Control Model for AlN/GaN/AlGaN Double Heterojunction Field-Effect Transistor

Abstract

Abstract:We have argued that the nature of surface potential variation with gate voltage of AlN/GaN/AlGaN Double Heterojunction Field Effect Transistor (DHFET) is no different from that of the conventional GaAs/AlGaAs HEMT devices. Necessary simulated band diagrams have been presented to justify our claim and we have also proposed a nonlinear expression for Fermi level (E F ) variation with the two-dimensional electron gas density (2DEG). We have showed that our proposed expression provides better agreement with the numerical solution than the previous approximations. Besides, expression of surface charge density (n s ) variation with gate voltage (V G ) obtained using our proposed model, shows better fit with the numerical simulation data in wide range of bias conditions.