Influence of AlGaN/GaN heterojunction parameters on its capacitance-voltage characteristics

Capacitance voltage technique provides substantial information on the charge distribution in heterojunctions. We used the simultaneous solution of the Poisson equation together with the drift and diffusion equations to simulate the voltage dependence of the AlGaN/GaN heterojunction structure, influence of several parameters of the structure as doping concentration of AlGaN and GaN, sheet carrier concentration of two dimensional electron gas, Schottky barrier height, and the thickness of the AlGaN layer on the resulting C-V curve of the heterojunction capacitor. The method enables to simulate the capacitance of the structure also in forward bias. It is shown how the simulation may be used for extracting the electrical parameters of experimental AlGaN/GaN heterostructures.