The initial stage of cubic silicon carbide (3C-SiC) growth on a Si(0 0 1) surface using dimethylsilane (DMS) as a source gas was observed using scanning tunneling microscopy (STM) and reflection high-energy electron diffraction (RHEED). It was found that the dimer vacancies initially existing on the Si(0 0 1)-(2 x 1) surface were repaired by the Si atoms in DMS molecules, during the formation of the c(4 x 4) surface. From the STM measurement, nucleation of SiC was found to start when the Si surface was covered with the c(4 x 4) structure but before the appearance of SiC spots in the RHEED pattern. The growth mechanism of SiC islands was also discussed based on the results of RHEED, STM and temperature-programmed desorption (TPD). (c) 2005 Elsevier B.V. All rights reserved.