Cree SiC Power White Paper: The Characterization of dV/dt Capabilities of Cree SiC Schottky diodes using an Avalanche Transistor Pulser

Rev. Introduction Since the introduction of commercial silicon carbide (SiC) Schottky diodes over 10 years ago, significant improvements in power factor correction (PFC) circuits and motor drives have been realized due to the elimination of minority carrier reverse recovery charge and its resulting switching loss associated with traditional PiN diodes. The early adoption of SiC Schottky diodes was somewhat hampered due to reliability issues, caused by unforeseen dV/dt limitations of the device. In particular, devices with lower dV/dt capability are more susceptible to failure from large in-rush currents. An initial investigation into the dV/dt of 600V SiC Schottky diodes found the upper limit of dV/dt to be 55-60V/ns (Volts per nanosecond) for these devices. As the diodes used in that study were not Cree® SiC Schottky diodes, follow-up studies were performed by researchers at Cree on their own 600V SiC Schottky diodes [1,2]. Their analysis found that the Cree diodes could withstand a turn-on rate of 75V/ns and a turn-off rate of 100V/ns for more than 100,000 cycles without failure. The end result of these and other studies is a motivation by diode manufacturers to report dV/dt ruggedness as a measure of SiC Schottky diode reliability.