Cottrell atmosphere formation in physical vapor transport grown 4H-SiC crystals

Abstract Possible interactions between point defects and dislocations during physical vapor transport (PVT) growth of 4H-SiC crystals were investigated using photoluminescence (PL) imaging and spectroscopy. Spatially diffuse PL-emitting regions were observed surrounding dislocations, including basal plane dislocations (BPDs) and threading dislocations, in PL images acquired using a 750 ± 25 nm band-pass filter. These diffuse PL-emitting regions around BPDs consistently exhibited a dark core at their center and extended more prominently along the basal plane than perpendicular to it. PL spectroscopy of these regions revealed an emission intensity peak at approximately 680 nm, which is attributed to carbon antisite–carbon vacancy pairs in 4H-SiC. Based on these findings, the formation of Cottrell atmospheres around dislocations in PVT-grown 4H-SiC crystals is discussed, and the temperature-dependent migration and transformation processes of point defects in the crystals are further elucidated.