Abstract: Basal plane dislocations (BPDs) critically influence silicon carbide (SiC) device performance. However, the relationship between their structure and properties remains unclear due to variable directions of BPDs on the basal plane. In this study, different BPD configurations were constructed with dislocation lines oriented perpendicular and parallel to the Burgers vector. First-principles simulation results revealed distinct electronic structures. Hereupon, BPDs were classified into screw-type and edge-type dislocations according to extinction criterion in X-ray topography. Meanwhile, a novel cross-diffraction vector method was developed to precisely identify the Burgers vector of screw-type BPDs. Notably, a supplemental photoluminescence peak at 427 nm for edge-type BPDs was firstly observed and the carrier recombination mechanism was proposed. Furthermore, edge-type BPDs preferentially formed under a convex temperature field during crystal growth driven by a higher formation energy compared to screw-type BPDs. Crucially, sectional observations revealed that edge-type BPDs transformed into Shockley stacking faults, while screw-type BPDs evolved into threading edge dislocations (TED) during epitaxy. This study not only advances the theoretical understanding of BPDs but also offers valuable guidance for optimizing defect engineering strategies, epitaxial growth processes, and dislocation enhanced 4H-SiC devices.

Key words: Basal plane dislocation, Properties and evolution mechanism, X-ray topography, Silicon carbide