Enhancement-Mode HEMT Performance and Mitigating Delay Through Double-Heterojunction With Connect Channel Utilization for Trap Effect Reduction

Abstract

This paper presents a GaN-based High Electron Mobility Transistor (HEMT) with a connected dual-channel structure (CDC-HEMT). Specifically, the Al0.05Ga0.95N layer beneath the first channel enables the second channel to be in a non-conducting state while simultaneously increasing the number of electrons available in the conducting state. In contrast to conventional normally-off devices, the CDC-HEMT exhibits excellent DC performance, with a saturation current density increase from 0.67 A/mm to 1.52 A/mm at Vds=10 V and a maximum transconductance increase from 0.30 S to 0.62 S, which is twice as much. Furthermore, the optimal transconductance interval is widened by 1 V. The RF performance of the devices also demonstrates remarkable performance, with a current gain cut-off frequency of 31.8 GHz and a maximum oscillation frequency of 77 GHz. Under square wave testing, the transistors exhibit extremely low delay. The exceptional findings showcased in this study provide compelling evidence that the CDC-HEMT structure is a highly promising technique for utilizing GaN-based HEMTs with superior performance in power switching and microwave applications.INDEX TERMS connect-dual-channel, double heterojunction, GaN normally-off HEMT, trap offset, P-GaN gate.