Effects of substrate cooling in hard magnetic disk sputtering process on protective overcoat and magnetic layer properties

An in-situ substrate cooling procedure has been carried out in a hard magnetic disk sputtering process to reduce the disk temperature prior to a deposition of a protective overcoat. The effects of cooling on the tribological and magnetic performance of the media are examined and directly compared for the amorphous carbon (a-C), amorphous hydrogenated carbon (a-C:H) and amorphous nitrogenated carbon (a-C:N) overcoat compositions. The substrate cooling procedure is shown to promote sp(3)-bonding character and to improve the tribological properties of the overcoats. To achieve the best tribological and magnetic performance of the media, the magnetic layer and the protective overcoat should be optimized as a coupled system. (C) 1998 Acta Metallurgica Inc.