1400V 4H-SiC power MOSFETs

Silicon Carbide (4H-SiC), power U-Metal-Oxide-Semiconductor Field-Effect Transistors (UMOSFETs) were fabricated and characterized from room temperature to 200 degrees C. The devices had a 12 mu m thick lightly doped n-type drift layer, and a nominal channel length of 4 mu m. When tested under Fluorinert(TM) at room temperature, blocking voltages ranged from 1.3 kV to 1.4 kV. Effective channel mobility ranged from 1.5 cm(2)/V.s at room temperature with a gate bias of 32 V (oxide field similar to 3.5 MV/cm) up to 7 cm(2)V.s at 100 degrees C with an applied gate bias of 26 V (oxide field similar to 2.9 MV/cm). Specific on-resistance (R-on,R-sp) was calculated to be as low as 74 m Omega.cm(2) at 100 degrees C under the same gate bias. Fowler-Nordheim measurements with positive gate bias on actual UMOS devices indicated thermionic field injection at elevated temperatures.