Novel double channel reverse conducting GaN HEMT with an integrated MOS-channel diode

Abstract

A novel normally-off double channel reverse conducting (DCRC) HEMT with an integrated MOS-channel diode (MCD) is proposed and investigated by TCAD simulation. The proposed structure has two features: one is double heterojunctions to form dual 2DEG channels named the 1st path and the 2nd path for reverse conduction, and the other is the MCD forming by the trench source metal, source dielectric, and GaN. At the initial reverse conduction stage, the MCD acts as a switch to control the 1st path which would be turned on prior to the 2nd path. Because of the introduction of the 1st path, the DCRC-HEMT has an additional reverse conducting channel to help enhance the reverse conduction performance. Compared with the conventional HEMT (Conv. HEMT), the DCRC-HEMT can obtain a low reverse turn-on voltage (V RT) and its V RT is independent of the gate–source bias (V GS) at the same time. The DCRC-HEMT achieves the V RT of 0.62 V, which is 59.7% and 75.9% lower than that of the Conv. HEMT at V GS = 0 V and −1 V, respectively. In addition, the forward conduction capability and blocking characteristics almost remain unchanged. In the end, the key fabrication flows of DCRC-HEMT are presented.