1.8 kV, 10 mOmega-square cm 4H-SiC JFETs (Preprint)

Abstract : Fabrication and characteristics of high voltage, normally-on junction field effect transistors (JFETs) in 4H-silicon carbide (4H-SiC) are presented. The devices were built on 5x10(exp 15) cm(exp -3) doped, 12 micron thick n-type epilayer grown on a n+ 4H-SiC substrate. A specific on-resistance of 10 mOmega-square cm and a blocking voltage of 1.8 kV were measured. Device characteristics were measured for temperatures up to 300 deg C. An increase of specific on-resistance by a factor of 5 and a decrease in transconductance were observed at 300 deg C, when compared to the value at room temperature. This is due to a decrease in bulk electron mobility at elevated temperature. A slight negative shift in pinch-off voltage was also observed at 300 deg C. The devices demonstrated robust DC characteristics for temperatures up to 300 deg C, and stable high temperature inverter operation in a power DC-DC converter application, using these devices, is reported in this paper.