Analysis of direct current performance on N-polar GaN-based high-electron-mobility transistors for next-generation optoelectronic devices

摘要

Exhibiting extremely high electric polarization, N-polar Group Ⅲ-nitrides heterostructure has been widely used on high-electron-mobility transistors (HEMTs) and terahertz photodetectors in recent years. In this paper, we numerically investigated an N-polar GaN/AlGaN/GaN HEMT device in which the two-dimension electron gas is induced at the top GaN/AlGaN interface. Characteristics of the device were determined by using experimental data to calibrate the few adjustable parameters of our simulations. Effects of interface charges on the device were researched by changing the component of Al. In addition, the dependency of scaling the device dimensions on direct current (DC) output characteristics, such as the gate length and the barrier height was also analyzed in details. Our simulations showed that increases of Al mole fraction and AlGaN barrier height and a decrease of the gate length can improve the DC performance of HEMT device to some extent. That could be a significant guidance for designing or optimizing the structure of N-polar GaN-based devices.