High‐Breakdown‐Voltage AlGaN Channel High‐Electron‐Mobility Transistors with Reduced Surface Field Technique

Abstract

In this article, reduced surface field (RESURF) AlGaN channel high‐electron‐mobility transistors (HEMTs) are proposed and investigated through 2D simulation for the first time. p+ doping is designed to form the RESURF structure, and the impact of the p+ doping density and length on breakdown characteristics is investigated. The breakdown voltage (BV) can be improved from 819 V for a conventional HEMT to 1746 V for a RESURF HEMT with a p+ doping density of 5 × 1018 cm−3 and length of 4 μm. Although the specific on‐resistance (RON) increases from 1.45 to 2.16 mΩ cm2, the power figure of merit (FOM) increases from 2.49 × 108 to 8.28 × 108 V2 Ω−1 cm−2 by utilizing a RESURF structure. By increasing the Al component of the RESURF AlGaN channel HEMT, the BV can be improved from 1746 to 2199 V. However, the RON also increases from 3.68 to 8.04 mΩ cm2, which leads to a decreasing of the power FOM. Simulation and analysis suggest that RESURF AlGaN channel HEMTs have great potential in power electronic applications.