Analysis of Defect-Related Electrical Fatigue in 4H-SiC Avalanche Photodiodes

SiC-based avalanche photodiodes (APDs) are the preferred devices for use in high-sensitivity UV detectors. However, the defect densities on the surface or in the bulk of the SiC epitaxial layer limit the performance of APDs. In this study, the effect of defects resulting in electrical fatigue in 4H-SiC APDs on device performance was analyzed. Further, fast and efficient defect analysis and detection methods based on laser scanning confocal microscopy are proposed for high-performance APD fabrication. Experimental results show a correlation between the electrical transport and optical properties with respect to the defect behavior in the active and non-active area based on the physical morphology.