A GaN RB-MISHEMT with a Schottky–MIS hybrid drain and An Al0−0.50Ga1−0.50N/GaN heterojunction

Abstract

In this work, a GaN reverse-blocking (RB) MISHEMT with a Schottky–MIS hybrid drain and a thin-upward-graded-Al0−0.50Ga1−0.50N/GaN heterojunction is proposed and investigated by TCAD Sentaurus. The Schottky–MIS hybrid structure incorporated in the drain terminal of the proposed device is employed to provide the device with decent reverse-blocking capability. Moreover, the double-electron barrier from the Schottky–MIS hybrid drain can also effectively suppress the drain-induced barrier lowering (DIBL) in devices with short MIS-controlled channel, subsequently enabling the device to exhibit more stable and less geometry-dependent characteristic, and much shorter reverse recovery time (~ ns) than the conventional RB-MISHEMT. To reduce the turn-on voltage of the Schottky-contact structure, a thin-upward-graded-Al0−0.50Ga1−0.50N barrier layer (the 10 nm Al0−0.50Ga1−0.50N barrier layer) is employed to replace the conventional thick fixed-Aluminum-role AlGaN barrier layer (the 25 nm Al0.23Ga0.77N barrier layer), subsequently causing the proposed device possessing a low drain offset voltage of 0.60 V and low on-state voltage of 1.80 V.