Gate Oxide Stability of 4H-SiC MOSFETs under On/Off-State Bias-Temperature Stress

Abstract

On- and off-state bias-temperature instability (BTI) measurements of 4H-SiC field effect transistors fabricated in a gate-oxide-first process were performed in the 30-450 °C temperature range. Stable operation under off-state stress at 300 °C is reported. On-state bias-instability stress revealed behavior consistent with the presence of hole traps in the SiC channel. The interface state density Dit increased from 2.5 eV-1cm-2 to 6.6 eV-1cm-2 as a function of positive stress duration.