Abstract: Heteroepitaxial growth of 3C-SiC on n-Si substrates has been performed by low pressure chemical vapor deposition process. The effects of different carbonized conditions and growth conditions on 3C-SiC films are investigated by optical profilometry and X-ray diffraction. The mechanism to reduce the 3C-SiC/Si warfer strain is discussed. The results show that the curvature of the wafer is reduced when the crystalline quality is improved. This can be interpreted that the crystalline quality improvement increases the intrinsic mismatch strain εm and compensates for the thermoelastic strain εθ , leading to the reduction of the residual strain. The best process condition is: carbonized temperature 1 000 ℃, carbonized time 5min, growth temperature 1 200 ℃, and growth rate 4 μm/h. High quality SiC epilayer has been obtained under the above condition and the epilayer curvature of the epilayer is only 5 μm/45 mm. The full-width at half maximum of the SiC(111) peak is 0.15°. The surface roughness is 15.4 nm.