Characterization of ultra-hard silicon carbide coatings deposited by RF magnetron sputtering

Silicon carbide films were deposited onto crystalline silicon substrates fr om a sintered SiC target using a RF magnetron sputtering system. The influe nce of substrate temperature (150-500 degreesC) and polarization (0-100 V), Ar pressure (0.05-4 Pa) and RF power (50-400 W) on the mechanical properti es (hardness and stress) of the resulting films was studied. Films with har dness values larger than 40 GPa could be obtained, provided that Si and C s puttered atoms can reach the surface of the growing film with sufficient hi gh energy and low deposition rates in order to guarantee a high surface mob ility. At high deposition rates the surface mobility is limited, but the in crease in substrate temperature can contribute to stress relief. Upon therm al annealing at high temperatures, completely stress-free films could be pr oduced without affecting the material hardness. This effect is accompanied by an increased structural and chemical order. Substrate bias was found not to be beneficial to the film properties, since it leads to substantial arg on incorporation into the material. (C) 2000 Elsevier Science B.V. All righ ts reserved.