Amorphous carbon-rich silicon carbide films Si0.45C0.55, deposited on silicon, were obtained by r.f. magnetron sputtering of sintered SiC targets in argon plasma and characterized by means of X-ray photoelectron spectroscopy, Auger electron spectroscopy, Rutherford backscattering spectroscopy and elastic recoil detection analysis. The structural evolution of these films upon thermal annealing at various temperatures in different atmospheres were investigated by means of Raman analysis and IR absorption. The formation of regions of crystallized SiC and diamond-like carbon as well as the hydrogen chemical state evolution are discussed in terms of chemical bondings. The processes of carbon segregation and crystallization of silicon carbide in the films are influenced by (i) high temperature treatments, (ii) annealing atmospheres and (iii) hydrogen dynamical behaviour.