Reliability issues of GaN HEMT: Current status and challenges

Abstract

With the development of power electronic devices, there is an increasing demand for energy-saving, emission reduction, and environmental protection. Thus, higher energy conversion efficiency of power electronic devices is required. While traditional Si-based power electronic devices have the disadvantage of low energy utilization efficiency and high thermal losses, GaN-based HEMT has significant advantages, making it a frontier and hotspot in global semiconductor research. However, the failure mechanisms that affect the reliability of GaN HEMTs are not completely comprehended. Many reliability issues affect devices performance, among which electrical reliability and thermal reliability are widely studied concerns. Electrical reliability issues contain inverse piezoelectric effect, hot electron effect, trapping effect, and mental instability. Thermal reliability issues contain self-heating effects, which are caused by the materials unsatisfying thermal conductivity, and improper structure design. This paper is focused on the current research results of the GaN HEMTs electrical reliability and thermal reliability. The first part of this paper gives a review of GaN HEMT reliability issues at their current status, and the second part outlines the challenges of GaN HEMTs in future development. This review will help researchers to better understand factors that affect GaN HEMTs reliability and help with their device design for further research.