Nucleation and growth behavior during initial stage in sublimation epitaxy of SiC films on 6H-SiC(0001) substrate

Abstract

The observation of silicon carbide (SiC) surface in the initial stage was carried out in order to understand the variation of surface configurations in a sublimation epitaxy. The surface structures with the nuclei and step flow depend on the process temperature, the process pressure. and the surface polarity. Step-flow configurations were observed at the surface on Si-face. On the other hand, an individual 2D island enlarged nuclei and the coalescenced islands formed on C-face (000-1) 6H-SiC occurred at the relatively low temperature of 1600 C due to the tensile stress analyzed by Raman spectroscopy. In addition, the nonuniform step-flow behavior on C-face surface was conspicuously exhibited at higher temperature of 1700-2100 degreesC, but the surface smoothness on C-face was better than that on Si-face. It was confirmed that several hidden parameters including rising rate until the wanted temperature and the final pressure give an effect on the surface configurations, but the decompression rate toward process pressure during temperature-rising stage reveals no change of surface configurations. (C) 2004 Elsevier B.V. All rights reserved.