2H-silicon carbide epitaxial growth on c-plane sapphire substrate using an AlN buffer layer and effects of surface pre-treatments

The effects of surface pre-treatments and the role of an AlN buffer layer for 2H-SiC growth on c-plane sapphire substrates by thermal CVD are investigated. While the crystallinity of SiC directly grown on sapphire substrate always degrades with a hydrogen pre-treatment but improves by optimizing carbonization, the crystallinity of SiC grown on sapphire substrate using an AlN buffer grown by MOCVD improves with sufficient time of exposure to the H pre-treatment but always deteriorates with carbonization. Detailed microstructural analysis by phi-scan x-ray diffraction reveals that SiC film grown on sapphire substrate consists of crystalline domains with two different crystallographic orientations which are rotated relative to each other along the [111] axis by 60°. A highly oriented hexagonal 2H-SiC film is obtained on low-cost c-plane sapphire substrate by using an AlN buffer. 2H-SiC is unambiguously determined not only by phi-scan x-ray diffraction but also by high-resolution transmission electron microscopy. The growth relationship between 2HSiC and 2H-AlN are coherent due to the favorable bonding of C and Al between SiC and AlN. Open image in new window