Single crystalline 3C‐SiC films were grown on a Si substrate by molecular beam epitaxy (MBE) using SiHCl3and C2H4gases. The optimal growth conditions were achieved at a growth temperature (Tsub) of 1000 °C and a gas pressure ratio (PSiHCl3/PC2H4) of 1/3 atPSiHCl3=1×10−5Torr. Prior to the essential growth of SiC, a carbonization process was performed with C2H4gas only. A continuous observation by reflection high‐energy electron diffraction (RHEED) was performed throughout the process of crystal growth. A series of RHEED patterns revealed that carbonization film could be grown at 750 °C and the lattice mismatch between Si and SiC crystals was satisfactorily relaxed. All processes of crystal growth were performed at a relatively low temperature.