The impact of parasitic inductance on the dV/dt ruggedness of 4H-SiC Schottky diodes

In this study, the dV / dt ruggedness of commercial 4H-SiC Schottky diodes C3D02060A (Wolfspeed) with DC blocking voltage of 600 V and continuous forward current of 2 A was investigated. The quasi-static reverse current-voltage characteristics of the diodes were measured in the recoverable avalanche breakdown regime up to currents of about 7 A. The mature avalanche breakdown voltage was measured to be 1180 V which is almost twice the rated blocking voltage of 600 V. The dV / dt tests were performed with the use of a pulse current generator capable of generating short (3 ns), high-current (up to 80 A), high-voltage (up to 4 kV at 50-ohm load) pulses. The d V / d t limit was found to be 1260 V/ns, in combination with the value of diode terminal voltage of 750 V. Based on TCAD simulations, the impact of unavoidable lead inductance of TO-220A package on the dV / dt limit is pointed out. It is shown that a high voltage is induced on semiconductor structure being higher than the voltage on diode external terminals. As a result, diode failure occurs, although the diode terminal voltage is significantly lower than the mature avalanche breakdown voltage of semiconductor structure. • The term “d V /d t ruggedness” is largely traditional. • A small series inductance can cause significant overvoltage resulting in failure. • The d V /d t limit was found to be 1260 V/ns. • Even extremely large dV / dt values may not lead to failure.