Experimental investigation of SiC 6.5kV JBS diodes safe operating area

This paper presents an experimental investigation of the dynamic performance of SiC 6.5kV JBS diodes. Using a hybrid Si SPT IGBT/SiC JBS diodes combination, we have analyzed the turn-off behavior limits of SiC JBS diodes and compared the result against a state-of-the-art Si PiN diode. The experimental results show that the JBS diodes can handle about 40A/chip at 125°C before going into thermal runaway. This maximum turn-off current value increases by about 50% when the diodes are operated at room temperature. The diodes dI/dt behaviour appear to be virtually independent of the DC-link voltage (at RG=18Ω). The comparison between turn-off curves for 6.5kV SiC and Si diodes shows that the use of SiC JBS diodes reduces the reverse recovery losses by more than 98%.