VF Degradation of 4H-SiC PiN Diodes Using Low-BPD Wafers

In this paper, we found different origin of forward voltage (V-F) degradation of SiC bipolar devices other than basal plane dislocations (BPDs) propagated from the SiC substrate. V-F degradation of the 4H-SiC PiN diodes with low-BPD wafers was evaluated and its origins were discussed. Some diodes suffered V-F degradation, even though they were fabricated on BPD-free area. Photoluminescence (PL) mapping, Transmission electron microscopy (TEM) image, and optical observation after KOH etching showed that there were Shockley stacking faults (SSFs) and combined etch-pits arrays, which were presumed to be caused by the device process.