Silicon Carbide JFET Cascode Switch for Power Conditioning Applications

Abstract

A new normally-off 4H-silicon carbide (SiC) cascode circuit has been developed capable of offering current densities approaching 500 A/cm/sup 2/. The cascode circuit boasts a specific on-resistance of 3.6 m/spl Omega/cm/sup 2/ and over 1000 V blocking capability. A low-voltage, normally-off SiC JFET is used as the controlling device in series with a high-voltage normally-on SiC JFET capable of blocking over 1000 V. The SiC cascode circuit is shown operable at temperatures exceeding 150/spl deg/C. Silicon carbide cascode circuit switching speeds show comparable speeds to typical Si power MOSFETs in the same voltage range. Clamped inductive load switching measurements are performed to demonstrate the cascode's reverse bias safe operating area (RBSOA) capability. Switching characteristics of the integral power diode are also demonstrated.