A Novel 4H-SiC SEMOSFET (Static channel Expansion MOSFET) was developed and a high performances, such as high blocking voltage, BV, of 5020V, low RonS of 88 mOmega cm(2) and high switching speed of less than 40ns, were achieved at the same time. In all reported FETs, the SEMOSFET has the best trade-off between RonS and BV and the largest figure of merit of 287MW/cm(2). Its RonS is about 1/140th that of the theoretical limit of Si MOSFET for this BV.