Mechanism of nitrogen incorporation in sublimation growth of SiC

Abstract

6H-SiC crystals have been grown on the Si-face and the C-face of 6H-SiC seed crystals by sublimation growth, respectively, and their deep photoluminescence (PL) have been investigated in detail. The deep PL spectrum of undoped 6H-SiC crystal grown on the C-face consisted of multiple broad emissions. On the other hand, undoped 6H-SiC crystal grown on the Si-face showed a single weak emission peak. In the case of the nitrogen-doped 6H-SiC crystals grown on the C-face, the emissions decreased with increasing nitrogen doping concentration and that of the nitrogen-doped 4H-SiC crystals grown on the C-face also showed the same behavior. As a C-vacancy is easy to form during the sublimation growth on the C-face, we think that nitrogen occupies the C-vacancy during the doping growth and leads to a decrease in the C-vacancy concentration as reflected by the PL analysis. We speculated that the difference in the doping concentration of nitrogen in the C-face and the Si-face-grown SiC crystal is related to the presence of the C-vacancy during crystal growth.