Comprehensive Investigations on Recovery Characteristics of Bias Temperature Instability in Planar and Trench SiC MOSFETs

Abstract

Gate-oxide degradation caused by bias temperature instability (BTI) is one of the most critical reliability issues for silicon carbide (SiC) metal–oxide–semiconductor field-effect transistors (MOSFETs). Nevertheless, the existing research on BTI recovery remains insufficiently comprehensive. In this study, the recovery characteristics of dc BTI and ac BTI in planar and trench SiC MOSFETs are comprehensively explored. It is found that both dc BTI and ac BTI can be recovered by short-circuit (SC) stress irrespective of the gate structure of the device. Notably, the larger the SC energy, the stronger the recovery ability. Excessive SC stress is more likely to induce additional threshold voltage drift in planar-gate devices. Furthermore, the threshold voltage redrift after recovery with the two methods of SC stress and the negative gate voltage plus high temperature are compared, revealing that SC stress yields a superior recovery outcome. From the perspective of device applications, these findings are believed to be helpful to suppress threshold voltage drift.