Self-heating and destruction of high-voltage 4H-SiC rectifier diodes under a single short current surge pulse

Abstract

Self-heating of high-voltage (6kV class) 4H-SiC rectifier p+–n–n+ diodes under the action of a single 20μs forward current surge pulse has been studied experimentally up to current densities j≈100kA/cm2. The diode parameters are stable after a single surge pulse with current density j≈60kА/cm2, although the estimated temperature of the diode at the end of this pulse is ∼1650K. After several pulses of this amplitude or after subjecting the diode to pulses with higher current density, the diode degrades. The degradation is manifested in an irreversible decrease of the differential resistance of the diode under a high forward bias. Even a single 20μs pulse with peak current density j≈100kA/cm2 leads to total destruction of the device.