Physics-based analytical models for p-GaN/AlGaN/GaN HEMTs considering gate charge emission

Abstract In this article, physics-based analytical models of channel charge density (2DEG: two-dimensional electron gas), gate capacitance and drain current have been proposed for normally-OFF p-GaN/AlGaN/GaN high electron mobility transistors (HEMTs). The models incorporate key physical phenomena, such as charge emission from the gate terminal via thermionic field emission and thermionic emission, as observed in prior studies on these devices. Notably, for the first time, the channel charge density is expressed explicitly as a function of gate voltage for p-GaN gated HEMTs, accounting for gate charge emission effects. This channel charge expression is subsequently employed to model gate capacitance and drain current for p-GaN gated HEMTs. Finally, the accuracy of the proposed models is rigorously validated using experimental and/or TCAD data for multiple p-GaN/AlGaN/GaN HEMT structures having diverse device parameters and for the reported range of gate and drain voltages. The robustness of the drain current model is further assessed under elevated temperature conditions. Moreover, the applicability of the proposed models is demonstrated for p-GaN gated HEMTs exhibiting low gate charge emission characteristics.