1.8 kV, 10 mOhm-cm2 4H-SiC JFETs

Fabrication and characteristics of high voltage, normally-on JFETs in 4H-SiC are presented. The devices were built on 5x10(15) cm(-3) doped, 12 mu m thick n-type epilayer grown on a n(+) 4H-SiC substrate. A specific on-resistance of 10 m Omega-cm(2) and a blocking voltage of 1.8 kV were measured. Device characteristics were measured for temperatures up to 300 degrees C. An increase of specific on-resistance by a factor of 5 and a decrease in transconductance were observed at 300 degrees 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 degrees C. The devices demonstrated robust DC characteristics for temperatures up to 300 degrees C, and stable high temperature inverter operation in a power DC-DC converter application, using these devices, is reported in this paper.