Silicon carbide JFET cascode switch for power conditioning applications

A new normally-off 4H-silicon carbide (SiC) cascode circuit has been developed capable of offering current densities approaching 500 A/cm². The cascode circuit boasts a specific on-resistance of 3.6 mΩcm² 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°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.