3C-SiC films have been grown on carbonized Si(100) using HMDS at 1350 degreesC. The surfaces of SiC films were very rough and a number of ridges were observed. The ridges were distributed over the surface probably along [110] and [<(1)over bar10>] directions. The surface of the carbonization layer at 1350 degreesC for 3min was characterized by AFM. The AFM result revealed many voids or grooves existing in carbonized layer. we think the reason of ridge growth results from the existence of grooves, because the CVD growth is controlled by diffusion process at the high temperature of 1350 degreesC, a high supersaturation of source gas occurred at knees of inhomogeneity of grooves. The growth rate at knees of grooves was very high so that many ridges appeared on the surface of SiC films. By adding appropriate amount HCl gas to CVD process, ridges can be removed due to a high HCl supersaturation at knees of grooves and the surface of SiC films became flatter compared with the growth using HMDS alone.