Consecutive stages of synthesizing epitaxial SiC films on n -type Si(111) and p -type Si(111) surfaces in a mixture of gaseous carbon monoxide and silane are studied by X-ray diffraction and Raman scattering methods. In films grown on an n -type Si(111) surface, only weak elastic deformations are observed during synthesis; however, in films grown on p -type Si substrates, relatively strong elastic deformations form, which are completely relaxed by the 40th min. It is found that the film structure is sharply changed at the third minute of the growth, which is related to the formation and growth of pores in the SiC layer. The differences of the lattice parameters of SiC films grown on n -Si and p -Si substrates are determined and confirmed by analyzing the change in the curvatures of the SiC/Si plates.