This study reports surface pre-treatment techniques for the formation of a high-quality graphene layer on a SiC surface. It is demonstrated that silicon passivation of SiC surface using a silane flow and subsequent sacrificial oxidation can significantly improve the surface condition of a graphene layer on SIC by ensuring much fewer carbon dumps and wrinkles, reducing the electrical resistance, and providing smoother surface roughness and a larger domain size. The effect of in situ cleaning by a SF(6) treatment before graphitization was also studied. It was found that in situ cleaning using SF(6) gas can be a simple and effective means of improving the quality of a graphene layer grown on SiC. The results of this study suggest that a surface treatment before graphitization is the key to synthesize high-quality epitaxial graphene layer. (C) 2009 Elsevier B.V. All rights reserved.