SiC thin films have been grown in situ on Si[100] substrates using a XeCl excimer laser (lambda = 308 nm). The films were deposited at different temperatures, from room temperature to 900 degrees C. The structure of the films was studied using modern analysis techniques, such as AES, XPS, TEM, STM, and IR. Polycrystalline alpha-SiC thin films grown on Si[100] substrates were obtained at 800 degrees C. The thin films were annealed at 1000 degrees C in a vacuum system. The effect of annealing disposition on the structure of the film was studied. TEM analysis shows that the annealed film has a hexagonal structure which includes 4H, 8H or 4H + 8H.