TCAD-Based Investigation of the Electrical Characteristics of Normally off p-GaN Passivated GaN HEMTs

This paper presents the influence of the energy level and concentration of acceptor or donor traps which could be introduced in the plasma passivation process on the saturation current of etch-free HEMTs. Acceptor traps in passivated pGaN region, and donor traps in SiNx/passivated pGaN and passivated pGaN/AlGaN interface are included in discussion. By the variation of the concentration and energy level of the trap, some general phenomena are discovered. In SiNx/passivated pGaN interface, the saturation current is proportional to the concentration and energy of donor traps. In passivated pGaN region, the saturation current shows negligible variations to the increase of concentration under 1×1018 cm-3 and the energy of acceptor traps. In passivated pGaN/AlGaN interface, the trend is the same as previous: the saturation current is proportional to the concentration and energy of donor traps. However, the saturation current is more sensitive to the change of donor trap concentration in this interface.