A Comparison of Short-Circuit Failure Mechanisms of 1.2 kV 4H-SiC MOSFETs and JBSFETs

Abstract

This paper presents a comparison of 1.2 kV 4H-SiC MOSFETs and Ti JBSFETs with deep P-well structures. For a fair comparison of the short-circuit characteristics between the MOSFETs and JBSFETs, an innovative design approach for the JBSFETs was implemented to obtain the same specific on-resistance to the MOSFETs. To improve the short-circuit characteristics of the MOSFETs and JBSFETs, channeling implantation was conducted to form a deep P-well structure, that helps reduce the maximum saturation current during the shortcircuit event. Using this approach superior short-circuit characteristics are achieved in the MOSFETs and JBSFETs. However, the JBSFETs provide a shorter shortcircuit withstand time than the MOSFETs due to the high leakage current from Schottky contact. Sentaurus 2D TCAD was used to understand and clarify the short-circuit mechanisms of the MOSFETs and JBSFETs. It was discovered that the MOSFETs failed due to the high current in the channel region, but the failure of JBSFETs happens in the Schottky contact. Moreover, solutions to improve the short-circuit characteristics of the JBSFETs are proposed; a narrow Schottky width and high work function metal.