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Bulk 3C-SiC growth by a sublimation method was carried out. The grown layer was used as a substrate for chemical vapor deposition, that is, homoepitaxial growth of 3C-SiC was carried out for the first time. The substrate exhibited some impurity-related photoluminescence peaks and no exciton-related peak was observed. The epilayer had some sharp exciton-related peaks near the band edge, which showed high crystallinity of the epilayer. Au Schottky barrier diodes were fabricated on the epilayer, and the diode showed good characteristics. The quality of 3C-SiC was improved by homoepitaxial growth.

The photoluminescence (PL) spectra of 3C-SiC epilayers grown on 15R-SiC and on 3C-SiC were measured. The PL spectra show strong exciton-related peaks and weak impurity-related peaks. The epilayers are of high quality and have a low density of impurities. Peaks due to excitons bound to neutral nitrogen showed very little shift induced by strain. Peaks considered to be due to free exciton recombination were observed and analyzed. Defect-related bands, usually observed for 3C-SiC grown on Si, were not observed. Although weak defect-related peaks were still observed, the epilayers have a lower density of defects than those on Si.

Crystal growth of cubic silicon carbide (3C-SiC) on ?-SiC (6H- and 15R-SiC) substrates was carried out by chemical vapor deposition. 3C-SiC (111) can be epitaxially grown on 6H- and 15R-SiC (0001) substrates. Due to the peculiar stacking sequence of ?-SiC, double positioning boundaries (DPBs) appear in the 3C-SiC (111) layers. The layer on 15R-SiC has far fewer DPBs than that on 6H-SiC. Successive etching of a thick grown layer and successive observation of a growing surface revealed that the DPBs decreased anisotropically as crystal growth proceeded. Facets formed along DPBs were analyzed by atomic force microscopy. The angles between the facets and the grown surface (111) varied with the crystallographic orientation of DPBs. DPBs may decrease due to the lateral growth from the facets. The difference in the velocities of the anisotropic decrease in DPBs was discussed on the basis of the number of dangling bonds on the facets.

Nucleation of GaN crystallites by sublimation method on sapphire (0001), scratched sapphire (0001), SiO2, Si (111), and metalorganic chemical vapor deposition(MOCVD)-GaN/sapphire (0001) was investigated. The density of the nuclei on SiO2and Si (111) was estimated to be 6 × 103/cm2. On the other hand, a continuous film rather than discrete crystallites was obtained on both the MOCVD-GaN and the scratched sapphire. Growth nucleation control was performed by partly covering the MOCVD-GaN or scratched sapphire (0001) with SiO2. As a result, hexagonal columns about 200 µm in diameter and 200 µm high were selectively and uniformly grown at the window sites. The diameter of each hexagonal column was much larger than the width of each window. This method can be used for device processing utilizing the crystallites.