Ultrathin TiSiN overcoat protection layer for magnetic media

TiSiN ultrathin films (10-50 A) deposited by reactive magnetron sputtering from TixSiy targets were used as anticorrosion overcoats to protect Co-containing recording media. Films' growth, structure, composition, resistance against hydrolysis, and anticorrosion performances were studied by spectroscopy (x-ray reflectivity and diffraction, ellipsometry, x-ray photoelectron spectroscopy, Fourier transform infrared reflection-absorption spectroscopy) and simulated by molecular dynamics (using modified Tersoff-type interatomic interactions). TiSiN ultrathin overcoats were found to be dense amorphous oxynitrides containing Ti-O-Si linkages. The conversion of SiNx into SiOx by hydrolysis was prevented by introducing less than 20 at. % of Ti in the films. Thanks to the formation of Ti-O-Si linkages which densify the films and reduce oxygen diffusion, good corrosion protection of the magnetic media was achieved down to 28 A TiSiN overcoat thickness.