(12) United States Patent ao) Patent No.: us 6,613,422 Bi
Ma et al. (45) Date of Patent: Sep. 2,2003
A method of forming a layer of a novel hard, abrasion and corrosion resistant, nitrogen-doped, high carbon density, amorphous carbon or hydrogenated carbon (C:H) protective overcoat material on a surface of a recording medium comprises steps of:
(a) providing a substrate including a stacked plurality of thin film layers thereon constituting the medium;
(b) forming, by a process comprising generation and deposition of C ions having energies of at least about 90 eV, a layer of an amorphous carbon or hydrogenated carbon (C:H) material on the at least one surface of the substrate, the C:H layer having a high carbon density of at least about 2.0 gm/cm3; and
(c) implanting nitrogen (N) ions in a surface portion of the high carbon density amorphous carbon or C:H layer to form an N-doped amorphous carbon or C:H surface layer having a carbon density substantially equal to said high C density of the C:H layer formed in step (b).
Embodiments of the invention include thin-film magnetic and magneto-optical recording media including a layer of the novel material as a protective overcoat.
9 Claims, 3 Drawing Sheets