Observations of Overlapped Single Shockley Stacking Faults in 4H-SiC PiN Diode

In 4H-SiC PiN diodes, Shockley-type stacking faults expand from basal plane dislocations under conducting forward current. We report for the first time overlapped single Shockley-type stacking faults in a 4H-SiC PiN diode after forward conduction. In photoluminescence measurements, we observed not only an emission peak at 425 nm, which corresponds to the single Shockley-type stacking fault, but also one at 432 nm. In cross-sectional cathode luminescence images, emission lines at 425 nm and 432 nm merge and become straight. Transmission electron microscope images showed that the structure at the position with the 432 nm emission overlapped the single Shockley-type stacking faults.