A Novel 6500 V SiC Trench MOSFET with Integrated Unipolar Diode for Improved Third Quadrant and Switching...

A 6500 V SiC trench MOSFET with integrated unipolar diode (UD-MOS) is proposed to improve reverse conduction characteristics, suppress bipolar degradation, and reduce switching loss. An N type base region under the trench dummy gate provides a low barrier path to suppress hole injection during the reverse conduction operation. The reverse conduction voltage V_ON is reduced to 1.11 V, and the reverse recovery charge (Q_RR) is reduced to 1.22 μC/cm². The gate-to-drain capacitance (C_GD) and gate-to-source capacitance (C_GS) of the UD-MOS are also reduced to improve switching loss due to the thick oxide layer between the trench gate and dummy gate. The proposed device exhibits an excellent loss-related figure of merit (FOM). It provides a high-voltage SiC MOSFET prototype with potential performance advantages for voltage source converter-based high voltage direct current applications.