Novel Designed SiC Devices for High Power and High Efficiency Systems

Two types of 4H-silicon carbide (SiC) MOSFETs are proposed in this paper. One is the novel designed V-groove trench MOSFET that utilizes the 4H-SiC (0-33-8) face for the channel region. The MOS interface using this face shows the extremely low interface state density (Dit) of 3 × 1011cm2eV-1, which causes the high channel mobility of 80 cm2V-1s-1results in very low channel resistance. The buried p+regions located close to the trench bottom can effectively alleviate the electric field crowding without the significant sacrifice of the increase of the resistance. The low specific ON-state resistance of 3.5 mQ cm2with sufficiently high blocking voltage of 1700 V is obtained. The other is the double implanted MOSFET with the carefully designed junction termination extension and field-limiting rings for the edge termination region, and the additional doping into the junction FET region. With a high-quality and high-uniformity epitaxial layer, 6 mm × 6 mm devices are fabricated. The well balanced specific ON-state resistance of 14.2 mQ cm2and the blocking voltage of 3850 V are obtained for 3300 V application.