Sputtered cobalt oxide for perpendicular magnetic recording medium with low media noise
Method of incorporating atomic oxygen into a magnetic recording layer by sputtering a target containing an oxide of cobalt. The oxide of cobalt may be sputtered to provide a readily dissociable source of oxygen which may increase the concentration of free cobalt atoms (Co) in the magnetic recording layer and also increase oxide content in the magnetic recording layer.
1. A method of forming a magnetic recording media, the method comprising:
providing a substrate; and
sputtering a target alloy including at least cobalt(Co), chromium (Cr), platinum(Pt), cobalt (II) oxide (CoO), and one or more non-cobalt oxides to form a magnetic recording layer over the substrate.
2. The method as in claim 1 , wherein the Gibbs energy (ΔG f ) of the one or more non-cobalt oxides is at least three times that of CoO.
3. The method as in claim 2 , wherein at least one of the one or more non-cobalt oxides is selected from the group consisting of: silicon dioxide, chromium oxides, titanium oxides, tantalum oxides, niobium oxides, and tungsten oxides.
4. The method of claim 3 , wherein at least one of the one or more non-cobalt oxides is selected from the group consisting of: silicon dioxide (SiO 2 ), titanium(IV) oxide (TiO 2 ).
5. The method as in claim 1 , wherein the target alloy includes a total amount of atomic oxygen between approximately 12 at. % and 25 at. % and the atomic oxygen from all non-cobalt oxides is approximately 20%-90% of the total amount of atomic oxygen.
6. The method as in claim 1 , wherein the target alloy further includes an amount of cobalt (Co) greater than the amount of cobalt present in the CoO.
7. The method as in claim 6 , wherein the target alloy further comprises a concentration of chromium (Cr) and platinum (Pt) to form a (Co x Cr y Pt 1−(x+y) ) metal alloy matrix doped with the one or more non-cobalt oxides and the CoO.
8. The method as in claim 1 , wherein a non-magnetic underlayer and a soft magnetic underlayer (SUL) is formed over the substrate prior to forming the magnetic recording layer of a perpendicular recording media (PMR).
9. The method as in claim 1 , wherein sputtering the target alloy further comprises:
providing, in a physical vapor deposition (PVD) chamber, a partial pressure of molecular oxygen (O 2 ) no greater than 2 mTorr to reactively sputter the target.
10. The method as in claim 9 , wherein the partial pressure of O 2 is 0.5 mTorr to 1.5 mTorr.
11. The method as in claim 1 , wherein sputtering the target alloy further comprises:
providing, in a physical vapor deposition (PVD) chamber, a negligible partial pressure of molecular oxygen (O 2 ) to non-reactively sputter the target.
12. The method of claim 1 , further comprising:
sputtering a second target alloy including a CoO and one or more non-cobalt oxides to form a capping layer over the magnetic recording layer, where the amount of CoO the second target alloy is less than that in the target alloy sputtered to form the magnetic recording layer.
13. The method of claim 1 , wherein the chromium (Cr) and platinum (Pt) form a CoCr x Pt y B z metal matrix, wherein x is between 10 and 22, y is between 10 and 25, and z is between 0 and 5.
14. The method of claim 13 , wherein the target alloy is CoCr x Pt y B z -(non-cobalt oxide) M -(CoO) N , wherein M is between 1 and 10 and N is between 1 and 15.
15. The method of claim 14 , wherein the non-cobalt oxide is selected from the group consisting of: silicon dioxide (SiO 2 ), chromium(III) oxide (Cr 2 O 3 ), titanium(IV) oxide (TiO 2 ), tantalum(V) oxide (Ta 2 O 5 ), niobium(V) oxide (Nb 2 O 5 ) and tungsten(II) oxide (WO 3 ).
16. The method of claim 15 , wherein the one or more non-cobalt oxide is TiO 2 with the (non-cobalt oxide) M -(CoO) N being one of: (TiO 2 ) 6 (CoO) 6 , CoCrPt—(TiO 2 ) 4 (CoO) 7 , or CoCrPt—(Ti0 2 ) 4 (CoO) 4 .
17. A deposition system for depositing a magnetic recording layer over a magnetic recording media, comprising:
a first target comprising an alloy including cobalt (CO), chromium (Cr), platinum (Pt), cobalt (II) oxide (CoO), and one or more non-cobalt oxides; and
a pallet to position a first recording media substrate surface proximate to the first target, wherein the first substrate includes a magnetic layer.
18. The deposition system as in claim 17 , further comprising:
a second target of substantially the same alloy composition as the first target positioned proximate to a second substrate surface.
19. The deposition system as in claim 17 , wherein the Gibbs energy (ΔG f ) of the one or more non-cobalt oxides is at least three times that of CoO.
20. The deposition system as in claim 17 , wherein the target alloy further includes an amount of cobalt (Co) greater than the amount of cobalt present in the CoO.
21. The deposition system as in claim 20 , wherein the target alloy further comprises a concentration of chromium (Cr) and platinum (Pt) to form a (Co x Cr y Pt 1−(x+y) ) metal alloy matrix doped with non-cobalt oxide and CoO.