Threading dislocation increase in the initial stage of growth of nitrogen and boron co-doped 4H-SiC by physical vapor transport

Abstract

In this study, n-type N-B co-doped 4H-SiC crystals were grown by the physical vapor transport method. We investigated the relationship between the boron concentration in the grown crystal and the mixing ratio of boron carbide (B4C) in the SiC source powder. In addition, we analyzed the relationship between the boron concentration and dislocation increase in the initial stage of growth. We found that an increase of threading dislocation occurred when the boron concentration was higher than 1 × 1019 cm−3 in the initial stage of growth. This threading dislocation increase can be suppressed by performing a pre-sublimation process of the mixed SiC and B4C powder.