SiC superjunction MOSFET with Schottky diode for improving short-circuit and reverse recovery ruggedness

In this article, a novel SiC superjunction MOSFET with Schottky diode containing N- and P -type barrier is proposed to improving short-circuit and reverse recovery ruggedness, investigated by TCAD simulations. The adoption of superjunction and p -shields structure can reduce saturation current, and thus, improve short-circuit capability. A fine gate oxide providing long-term reliability of the device is obtained. Also, N -type Schottky diode for electrons is used to dampen bipolar conduction of the parasitic body diode, while P -type Schottky diode for holes is introduced to constrain the hole inflow and extraction attributed to the transient variation of the superjunction. As a result, compared with an SBD-wall-integrated trench MOSFET (SWITCHMOS), a low on -resistance and high breakdown voltage of the proposed structure are gained. More importantly, the proposed device exhibits stronger temperature -dependent immunity. As expected, simulation results indicate that the proposed device under 10 nH stray inductance shows a 30%-50 % reduction in the peak reverse recovery current and a 50%-70 % decrease in the current rising slope of reverse recovery, compared to only a single superjunction, when the metal workfunction varies from 5.1 to 5.6 eV. Moreover, the short-circuit withstanding time of the proposed structure increases roughly 2 times longer than that of SWITCH-MOS.