Single crystal 3C-SiC (111) films were grown on SiNx/Si (111) structures fabricated by both ammonia nitridation of the Si surface with SiNx and RF-magnetron sputtered SiNx deposition. The nitrided Si substrates accommodated the growth of better quality SiC films with a flat and smooth film/substrate interface than a pure Si substrate. The crystallinity of SiC layers improved as the nitridation time increased. It seemed that the growth of better quality of SiC films was ascribed to the prevention of Si out-diffusion from the substrate by the coverage of Si with the thermally stable silicon nitride film and to the decrease of Si surface roughness. Crystalline 3C-SiC films was also grown on 3000 Angstrom thick SiNx/Si structure.