Analysis of Various Breakdown Voltage Improvement Techniques for E-mode AlGaN/GaN HEMTs

Abstract

E-mode HEMTs featuring a p-GaN gate with 2D (2-dimensional) electron gas at the AlGaN/GaN interface demonstrate a substantial density and exceptional mobility of carriers. This characteristic positions them as potential contenders for applications demanding both high frequency and high power. For high-power circuit applications, E-mode HEMTs with high breakdown voltage are desired, which have a significant influence on AlGaN/GaN HEMT performance. From this perspective, even though several approaches for enhancing the breakdown voltage of E-mode HEMTs have been documented in literary works, the most promising approach for advancing circuit integration and device miniaturization in upcoming power electronics systems appears to be the recent approach involving E-mode HEMTs featuring a p-GaN gate with GaN/AlN buffer layer reshaping. This innovative approach has demonstrated a remarkable breakdown voltage of up to 1781 V. The objective of this work is to comprehensively examine and analyze various methodologies designed to elevate the breakdown voltage in high-power E-mode HEMTs featuring a p-GaN gate. Initially, the underlying mechanisms accountable for breakdown are discussed. Subsequently, a concise overview of several approaches aimed at elevating the breakdown voltage in E-mode HEMTs is briefly mentioned. Finally, a novel approach that involves reshaping the hybrid GaN/AlN buffer layer to increase the breakdown voltage in E-mode HEMTs featuring a p-GaN gate is discussed.