Characterization of 4.5 kV Charge-Balanced SiC MOSFETs

Abstract

This work demonstrates a novel charge-balanced (CB) silicon carbide (SiC) MOSFET that boasts a specific on-resistance of 10 mΩ•cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> at 4.5 kV breakdown voltage, surpassing the 1-D SiC unipolar limit. This is achieved through buried p-doped regions inside the drift layers, which are more easily scalable to higher voltages compared to the p-doped pillars used in super-junction (SJ) devices. Medium-voltage CB SiC MOSFETs with different p-doped bus widths and pitches have been fabricated and characterized in this work. The unique microstructure of these devices causes interesting macro-scale characteristics, such as distinctive steps in the capacitance–voltage curves and a turn-on voltage tail that reduces with increased temperature. The switching energy of the CB MOSFET is 92% lower than that of an IGBT at 150 °C. This paper presents and interprets these intriguing static and dynamic characteristics.