Ruggedness evaluation of 56mm2, 180 A SiC DMOSFETs as a function of pulse repetition rate for high power applications

Modern power electronics systems try to maximize power density and efficiency. As such, the active switch is required to safely handle very stressful transient conditions. A 56 mm², 180 A, SiC DMOSFET manufactured by Cree Inc. is evaluated by electrically stressing the device in a RLC ring-down test system capable of producing peak current in excess of 600 A (>3X rated current) and di/dt´s as high as 860 A/μs. The device was hard-switched 5,000 times at repetition rates of 1, 2, 5, and 10 Hz for a total of 20,000 switching events. The device characteristics were monitored every 1,000 shots on a high power curve tracer to determine device degradation. The devices showed no changes in blocking characteristics and minimal changes in on-state characteristics due to shifts in the threshold voltage after 20,000 hard switching events. The threshold voltage shifts over the test period are minimal with a +/- 93 mV deviation from the average of 4.39 V. With the stability of the threshold voltage, on-state characteristics, and blocking characteristics; this shows that this device would perform reliably within commercial applications that include stressful switching conditions.