SiC Damage Induced by Heavy Ion Irradiation and Post-Gate Stress in SiC MOSFETs

This study provides a detailed investigation of the anomalous SiC damage morphology and associated failure mechanisms in SiC MOSFETs. The devices were irradiated with Tantalum (Ta) ions at a linear energy transfer (LET) value of 80.7 MeV·cm²/mg under a drain bias of 80 V. Following irradiation, the post irradiation gate stress (PIGS) test was performed to trigger oxide breakdown and the adjacent SiC damage. Distinctive SiC damage characteristics are identified through failure techniques, including a semicircular anomalous surface damage zone connecting an elongated bulk damage trace. Additionally, a localized crystal arrangement region is also detected in the upper of the damage trace. Further analysis reveals that the anomalous damage morphology results from synergistic interaction between initial ion strikes and subsequent PIGS test. The effects of ion strikes and the subsequent SiC structural disruption processes during PIGS test are further discussed. This experimental finding contributes to a more comprehensive understanding of the damage mechanism in SiC MOSFETs exposed to irradiation and electrical stress.