Basal plane dislocation multiplication via the Hopping Frank-Read source mechanism in 4H-SiC

Abstract

Synchrotron white beam x-ray topography (SWBXT) observations are reported of single-ended Frank-Read sources in 4H-SiC. These result from inter-conversion between basal plane dislocations (BPDs) and threading edge dislocations (TEDs) brought about by step interactions on the growth interface resulting in a dislocation comprising several glissile BPD segments on parallel basal planes interconnected by relatively sessile TED segments. Under stress, the BPD segments become pinned by the TED segments producing single ended Frank-Read sources. Since the BPDs appear to “hop” between basal planes, this apparently dominant multiplication mechanism for BPDs in 4H-SiC is referred to as the “Hopping” Frank-Read source mechanism.

Influence of the growth interface shape on the defect characteristics in the facet region of 4H-SiC single crystals

“…The reduction of the TEDs by 60% is probably due to a conversion into BPDs. The large surface steps deflect some of the TEDs into BPDs, as it was also observed to occur in PVT grown SiC in [13]. Yakimova et al in [14].…”

10 Effect of pulse current on micro-hardness and wear performance of cold-rolled T2 copper sheet

“…It also greatly reduced the dislocation density in the copper sheet. Based on Frank-Read (F-R for short) dislocation source mechanism, the proliferation of original dislocations has led to the generation of new dislocations [21]. Therefore, the original dislocation density has a certain effect on the increment of dislocation after surface wear.…”

Basal plane dislocation-threading edge dislocation complex dislocations in 6H-SiC single crystals

“…On the other hand, the reverse conversion is not energy favored. Wang et al 15 thought this conversion results from the deflection of surface outcrop of a TED onto the basal plane by a macrostep and create a BPD, this is a plausible reason. From our study, the deviation of a BPD line from the basal plane seems to result from the interaction of TED and BPD.…”

“…TEM study reveals that complex dislocations consist of BPDs and TEDs connected alternately each other. By using synchrotron white beam X-ray topography, Wang and coworkers 15 found that TED and BPD can convert each other and the BPD multiplies through hopping Frank-Read source with TED serving as pinners in 4H-SiC.…”