8 kV Normally-off All-SiC Cascode Power Switch Using VJFETs

We demonstrate an 8 kV, 3 A cascode power switch using SiC VJFETs for both the normally-on and normally-off devices. The normally-on SiC VJFETs have blocking voltages greater than 8 kV at V
_GS
=-50 V pinch-off voltage and on-state currents of more than 4 A at V
_GS
=0 V. The normally-off SiC VJFETs block 70 V (V
_GS
=0 V) and can drive >2 A/device with positive gate voltage (V
_GS
=2.5 V). The VJFETs were combined into a module to create the 8 kV all-SiC cascode switch that blocks 8 kV normally-off and drives 3 A of on-state current. Preliminary switching measurements show very fast rise and fall times.