Enhancing the Short-Circuit Capability of SiC MOSFETs by Utilizing the Leakage Current of Schottky Diodes

Enhancing the short-circuit capability of SiC MOSFETs by utilizing the leakage current of Schottky barrier diodes is proposed. This structure integrates a reverse-biased Schottky barrier diode at the gate, with the anode and cathode of the Schottky barrier diode being short-circuited to the source and gate of the SiC MOSFET, respectively. When the device is short-circuited, the junction temperature and leakage current of the Schottky barrier diode will increase with the increase of short-circuit time, which will lead to a decrease in gate voltage. Reducing the gate voltage decreases the drain-source current, thereby suppressing the junction temperature rise. The simulation results show that the gate integrated Schottky barrier diode does not increase the on-resistance of the device. Additionally, the SiC MOSFET with integrated Schottky barrier diode on the gate has a maximum junction temperature of approximately 903 K after a short-circuit time of 20 μ s. Compared with SiC MOSFETs without integrated reverse biased Schottky barrier diode on the gate, SiC MOSFETs with integrated reverse biased Schottky barrier diode on the gate have significantly improved short-circuit capability. In addition, Schottky barrier diode increase the equivalent capacitance between the gate and source, improving the device's ability to prevent false turn-on.