SiC MOSFET With Embedded Polysilicon Diode for Improved Short-Circuit Capability and Electrical Characteristics

A novel SiC MOSFET with embedded polysilicon diode (PSD-MOS) is proposed in this letter. The PSD, which is formed through intentional doping within the polysilicon gate, is connected in anti-parallel with the GS terminal of the SiC MOSFET. When a short-circuit (SC) event occurs, the lattice temperature of device rises significantly. Leveraging the temperature-dependent reverse leakage characteristic of the PSD, the voltage distribution across the drive loop composed of the drive, gate resistance <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">G</sub>, and GS terminal is effectively regulated. As a result, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">GS</sub> is reduced, accompanied by a decrease in SC current, thus enabling the safe turn-off of the device ultimately. TCAD simulations demonstrate that the PSD-MOS can even provide complete immunity against SC failure. Furthermore, in comparison to the conventional SiC MOSFET (C-MOS), its electrical characteristics are notably enhanced, as evidenced by reduced capacitance, gate charge, and switching losses. This indicates that the proposed PSD-MOS holds significant potential for high-reliability and high-performance applications.