Effect of basal plane dislocation structures on single Shockley-type stacking fault expansion rate in 4H-SiC

The expansion rate of single Shockley-type stacking faults (1SSFs) was examined in 4H-SiC under UV illumination in various basal plane dislocation (BPD) structures with 90° or 30° Si-core partial dislocations (PDs) at the expansion front. In the case of 30° Si-core PDs at the front, we found some BPDs with extremely slow expansion rates. Photoluminescence imaging revealed that the BPDs were accompanied by characteristic dim lines in the shallower parts of the epitaxial layers. We confirmed that the lines were threading edge dislocations by transmission electron microscopy. Additional high-resolution scanning transmission electron microscope analysis revealed that the leading partial was a 30° C-core instead of a 30° Si-core. This implies the large amount of C-core segments on the expanding PD might be the reason for the 1SSFs having very slow expansion rates. Moreover, the expansion rate of 90° Si-core PDs was obtained experimentally and compared with that of 30° PDs.