AlGaN/GaN HEMT AC/DC Performance Analysis of Conventional and Gate Recessed MOS-HEMT With Temperature Variation

Abstract

AlGaN/AIN/GaN based conventional and recessed gate high electron mobility transistors (HEMTs) having Al2O3 gate oxide have been investigated for comprehensive understanding of the effect of temperature on its AC and DC performance. Threshold voltage shows lower dependence on temperature as compared to other DC parameters. The recessed structure presents an opportunity to control its threshold voltage by proper etching depth as it selectively decreases two dimensional electron gas (2-DEG) only below gate to have precise control on channel. The threshold voltage of MOS-HEMT is −2.3 V which shifts upto 0.2 V for the different recessed gate HEMT etch depths however recess device has lower ON current of 0.7 A/mm with respect to 0.81 A/mm for conventional device. The simulations for both devices were performed on Atlas device simulation tool and results show a degradation of transfer characteristics, output characteristics, transconductance and frequency response with the increase in temperature. Therefore proper operating point is a must condition for appropriate and reliable operation of device.