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

The effects of the introduction of H2, O2, and N2 during high-rate sputtering on the magnetic properties of resulting Co-Cr film were studied. O2 and N2 react with the Co-Cr to form compounds. Addition of N2 induces an fcc ≪200≫ orientation perpendicular to the film plane, thereby causing a drastic decrease in the perpendicular anisotropy field Hk, accompanied by degradation in the hcp ≪002≫ orientation. O2 is the most reactive with Co-Cr, but has little effect on the crystal structure. These effects are diminished at higher deposition rates for the same gas pressure. In contrast, H2 does not react with Co-Cr at all, but plays a unique role in that it changes the coercive force without any accompanying change in Hk or the crystal orientation. The effects of N2 and H2 are concluded to be equivalent, respectively, to the effects of raising and of lowering the substrate temperature.