The surge failure mechanisms of 1200-V/40-A 4H-SiC junction barrier Schottky diodes with various epilayer defects

Abstract

The surge reliability and failure mechanisms of 1200-V/40-A 4H-SiC junction barrier Schottky diodes with different epilayer defect types have been studied in depth. Under 2500 surge current cycles with Ipeak = 190 A conditions, it is observed that the particle inclusions, triangular defects, surface particles, and stacking faults exhibit varying degrees of significant effects on the conduction, breakdown, and surge characteristics of the diodes. The results indicate the presence of three distinct failure mechanisms that are attributed to epilayer defects being activated and expanded at high current and high junction temperature, accelerating the premature failure of the devices in the iterative process of thermo-electric coupling. One mechanism involves defect-induced current paths damaging the Schottky barrier interface within the active region, directly leading to the loss of the device’s blocking and surge capabilities. The other mechanisms relate to defect-related damage in the termination region, which also triggers varying degrees of degradation in the breakdown voltage and surge capability.