Effects of Additive Gases on Properties of Co-Cr Film Media During High Rate Sputtering

Impurity gases during sputtering can have serious effects on magnetic properties of a Co-Cr perpendicular recording medium. Research into the effects of N2, O2 and H2 additive gases on Co-Cr films of thickness around 2000 Å produced by high-rate continuous sputtering indicates that when the partial pressure of N2 as impurity of Ar sputtering gas reaches 10^¿5 Torr, the hcp c-axis perpendicular orientation deteriorates and hence, the perpendicular anisotropy degrades. When the N2 partial pressure increases above 10^¿5 Torr, even the structure of the film changes from hcp to fcc. N2 and O2 are reactive and causes drastic reduction of the perpendicular anisotropy field of Co-Cr films, but H2 does not effect Hk and even slightly improves the squareness of perpendicular M - H loop of films.