Seed layer comprising FCC structure
An apparatus and method are provided for improving perpendicular magnetic recording media. The present invention provides media, and a method of fabricating media in a cost-effective manner, with a reduced ruthenium (Ru) content interlayer structure, while meeting media performance requirements. A perpendicular magnetic recording medium is provided comprising a non-magnetic substrate having a surface, and a layer stack situated on the substrate surface. The layer stack comprises, in overlying sequence from the substrate surface a magnetically soft underlayer; an amorphous or crystalline, non-magnetic seed layer; an interlayer structure for crystallographically orienting a layer of a perpendicular magnetic recording material situated on the underlayer; and at least one crystallographically oriented, magnetically hard, perpendicular magnetic recording layer situated on the interlayer structure. The interlayer structure is a stacked structure comprising, in overlying sequence: a chromium alloy situated on the seed layer; and an upper interlayer situated on the chromium alloy.
1. A method comprising:
forming a seed layer comprising a face-centered cubic (FCC) structure overlying a substrate;
forming a dual-layer interlayer structure comprising a first interlayer and a second interlayer,
wherein forming the first interlayer comprises forming a chromium alloy interlayer by sputter deposition in a gas atmosphere at a first pressure such that the first interlayer is overlying the seed layer, and
wherein forming the second interlayer comprises forming the second interlayer by sputter deposition in a gas atmosphere at a second pressure greater than the first pressure such that the second interlayer overlies the chromium alloy interlayer; and
wherein the second interlayer comprises a <0002> growth orientation; and
forming a magnetic layer overlying the second interlayer.
2. The method as in claim 1 , wherein the second interlayer is formed with a ruthenium alloy.
3. The method as in claim 1 wherein the second interlayer is formed at about 2 nm to about 7 nm thick.
4. The method as in claim 1 , wherein the chromium alloy interlayer is of a general formula CrX, wherein X is at least one selected from the group consisting of: Mo, W, Co, Zr, V, Ta, TiO β , SiO β , WO β , NbO β , and TaO β , and wherein in β is within a range of 2 to 3.
5. The method as in claim 1 , wherein the first interlayer is formed at about 1 nm to about 15 nm thick.
6. The method as in claim 1 , wherein the chromium alloy interlayer is sputter deposited at a pressure ranging from 0.5 mtorr to 120 mtorr.
7. The method as in claim 1 , wherein the seed layer is non-magnetic, and wherein the seed layer comprises a nickel-based, FCC-phase alloy; copper; gold; or silver.
8. The method as in claim 1 , wherein the interlayer structure is a body centered cubic (BCC) structure.