The initial stage of cubic silicon carbide (3C-SiC) growth on Si(0 0 1)-2 x 1 surface was observed using monomethylsilane (MMS) as source gas at 650-750 degreesC by reflection high-energy electron diffraction (RHEED) and atomic force microscopy (AFM). The growth characteristics were compared with those in the case of dimethylsilane (DMS). Prior to the appearance of SiC spots, RHEED pattern of Si c(4 x 4) structure appeared, as in the case of DMS. From the variation in the RHEED intensity with time, the activation energy for the initial growth rate of SiC was very close to that in the case of DMS. From these facts, the rate determining step of the SiC initial growth was considered to be the same in both cases. From the AFM images of substrate surface after SiC nucleation, however, the surface morphology was different between the case using MMS and that using DMS. (C) 2003 Elsevier Science B.V. All rights reserved.