High-frequency AlGaN/GaN T-gate HEMTs on SiC Substrate

Abstract

This paper investigates the DC and AC performance of T-gate Gallium Nitride (GaN) High Electron Mobility Transistors (HEMTs), with a particular emphasis on their high-frequency characteristics under various structure parameters and conditions. The study delves into the impact of different gate structures and the concentration of traps on the RF performance of the devices, including those at the AlGaN/GaN interface and within the GaN buffer layer. Moreover, the analysis includes the examination of short channel effects that can significantly influence the device behavior when the gate length is less than 100nm. Through comprehensive simulations, optimal structural parameters were identified, leading to notable advancements in device performance. Specifically, the devices achieved a remarkable cut-off frequency of 138 GHz and a maximum oscillation frequency of 192 GHz, accompanied by an extremely low gate leakage current, which is lower than 1E-8 mA/mm. These findings highlight the potential of T-gate GaN HEMTs in high-frequency applications.