A self-clamped L-shaped trench gate SiC MOSFET with Improved Breakdown and Short-Circuit Reliability

A novel self-depleting L-shaped channel SiC trench MOSFET (SCL-TMOS) has been proposed and analyzed using a TCAD simulator. By extending the p-base region to the bottom of the trench gate through deep P-well injection, the SCL-TMOS better shields the gate oxide from high electric fields in the off state. This enhancement allows for an increased breakdown voltage without significantly degrading output characteristics. Additionally, the introduction of the self-depletion mechanism reduces the peak current of the device during short-circuit conditions, improving the short-circuit tolerance. Compared to conventional SiC trench MOSFETs, the peak electric field value in the gate oxide is reduced by 64.9%. Furthermore, the breakdown voltage has increased by 13.7%. The capacitance of HW-TMOS has been optimized by converting the gate-drain capacitance (C<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">gd</inf>) at the trench gate sidewall into gate-source capacitance. The short-circuit robustness time of SCL-TMOS is improved by 66.7% compared to C-TMOS. Overall, SCL-TMOS meets the high demands for power devices in modern electronic equipment.