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Silicon carbide (SiC) unipolar devices have much higher breakdown voltages than silicon (Si) unipolar devices because of the ten times greater electric field strength of SiC compared with Si. 4H-SiC unipolar devices have higher switching speeds due to the higher bulk mobility of 4H-SiC compared to other polytypes. In this paper, four commercially available SiC Schottky diodes with different voltage and current ratings, VJFET, and MOSFET samples have been tested to characterize their performance at different temperatures ranging from -50°C to 175°C. Their forward characteristics and switching characteristics in this temperature range are presented. The characteristics of the SiC Schottky diodes are compared with those of a Si pn diode with comparable ratings.

Bi-directional solid-state circuit breakers (BDSSCBs) can provide performance benefits over mechanical fault protection devices. A common-source configuration of normally ON, junction field effect transistors (JFETs) is favorable for BDSSCB implementations. SiC 0.1-cm² 1200-V JFETs designed for normally-ON operation at a zero-volt gate bias, and having low leakage currents, were used in the fabrication of a 30-A BDSSCB switch module. Operation of the module under continuous current and during turn-OFF transitions was evaluated to verify the parallel scalability of the common-source configuration. A bi-directional snubber connected across the switch module mitigated inductive voltage overshoot during BDSSCB turn-OFF transitions. At turn-OFF, under maximum power tests in both directions, the load current was reduced from 30 A to 0 A in approximately 10 μs, with a supply voltage of 600 V, and a BDSSCB peak voltage of 680 V. These results demonstrate the functionality and current scalability of this BDSSCB topology.

Silicon carbide (SiC) unipolar devices have much higher breakdown voltages than silicon (Si) unipolar devices because of the ten times greater electric field strength of SiC compared with Si. 4H-SiC unipolar devices have higher switching speeds due to the higher bulk mobility of 4H-SiC compared to other polytypes. In this paper, four commercially available SiC Schottky diodes with different voltage and current ratings, VJFET, and MOSFET samples have been tested to characterize their performance at different temperatures ranging from -50°C to 175°C. Their forward characteristics and switching characteristics in this temperature range are presented. The characteristics of the SiC Schottky diodes are compared with those of a Si pn diode with comparable ratings.