Systems and Methods for Locally Reducing Oxides

• US 20150194261A1
• Filed: 01/08/2015
• Published: 07/09/2015
• Est. Priority Date: 01/08/2014
• Status: Active Grant

• Current Assignee: University of Houston System
• Original Assignee: University of Houston System
• Inventors: Litvinov, Dmitri, Chang, Long
• Granted Patent: US 9,818,535 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: C23C 14/0036 Reactive sputtering
• CPC Class Codes: C23C 14/085 of iron group metals
• CPC Class Codes: C23C 14/5806 Thermal treatment
• CPC Class Codes: C23C 14/5846 Reactive treatment
• CPC Class Codes: G11B 5/65 characterised by its composition G11B5/66 takes precedence
• CPC Class Codes: G11B 5/658 containing oxygen, e.g. molecular oxygen or magnetic oxide
• CPC Class Codes: G11B 5/855 Coating only part of a support with a magnetic layer
• CPC Class Codes: H01F 10/123 having a L10 crystallographic structure, e.g. [Co,Fe][Pt,Pd] thin films
• CPC Class Codes: H01F 10/14 containing iron or nickel H01F10/126 , H01F10/13, H01F10/16 take precedence
• CPC Class Codes: H01F 10/16 containing cobalt H01F10/126 , H01F10/13 take precedence
• CPC Class Codes: H01F 41/22 Heat treatment; Thermal decomposition; Chemical vapour deposition

Abstract

In the systems and methods for synthesizing a thin film with desired properties (e.g. magnetic, conductivity, photocatalyst, etc.), a metal oxide film may be deposited on a substrate. The metal oxide film may be achieved utilizing any suitable method. A reducing agent may be deposited before, after or both before and after the metal oxide layer. Oxygen may be removed or liberated from the deposited metal oxide film by low temperature local or global annealing. As a result of the annealing to remove oxygen, one or more portions of the metal oxide may be transformed into materials with desired properties. As a nonlimiting example, a metal oxide film may be treated to provide a magnetic multilayer film that is suitable for bit patterned media.

Claims

1. A method for reducing a metal oxide layer, the method comprising:

depositing a metal oxide layer on a substrate;

depositing a reducing agent on the substrate to aid removal of oxygen from the metal oxide layer; and

annealing the substrate to remove oxygen from the metal oxide layer, wherein the annealing results in improving magnetism, conductivity, photocatalyst, or refractive index properties of the metal oxide layer.

2. The method of claim 1, wherein the metal oxide layer is a cobalt oxide, CoO, CoOPd, CoOPt, Fe₂O₃, Fe₃O₄, iron oxide, CuO, Cu₂O, copper oxide, TiO₂, tin oxide, manganese oxide, chromium oxide, nickel oxide, silver oxide, or molybdenum oxide.

3. The method of claim 1, wherein the metal oxide layer is a patterned layer.

4. The method of claim 1, wherein the reducing agent is deposited before, after, or both before and after the metal oxide layer.

5. The method of claim 1, wherein the reducing agent is Ta, Al, Mg, Ca, Zr, Zn, Ti, Si, C, or H₂.

6. The method of claim 1, wherein an annealing time is equal to or between 0.1 nanoseconds to 24 hours.

7. The method of claim 1, wherein an annealing time is 5 minutes or greater.

8. The method of claim 1, wherein an annealing temperature is equal to or greater than 100°

C.

9. The method of claim 1, wherein an annealing temperature is equal to or between 100-1000°

C.

10. The method of claim 1, wherein an annealing temperature is equal to or between 100°

C. to 500°

C.

11. The method of claim 1 wherein the metal oxide layer is a cobalt oxide, CoO, CoOPd, CoOPt, iron oxide, Fe₂O₃, Fe₃O₄, or nickel oxide.

12. The method of claim 1, wherein the annealing step comprises heating localized areas to pattern the metal oxide layer, and an annealed metal oxide layer provides one or more patterned islands with oxygen removed.

13. The method of claim 12, wherein the substrate and the annealed metal oxide layer are bit patterned media (BPM).

14. The method of claim 13, wherein the BPM has a defect density of 15% or less variation in switching properties.

15. The method of claim 13, wherein the BPM has a defect density of 10% or less variation in switching properties.

16. The method of claim 13, wherein the BPM has a defect density of 5% or less variation in switching properties.

17. A method for forming bit pattern media (BPM), the method comprising:

depositing a media layer comprising a metal oxide on a substrate, wherein the metal oxide demonstrates magnetic properties when oxygen is removed;

depositing a reducing agent on the media layer to aid removal of oxygen; and

locally annealing the media layer, wherein the local annealing heats a plurality of regions of the media layer and the plurality of regions form a matrix of magnetic islands.

18. The method of claim 17, wherein the metal oxide is a cobalt oxide, CoO, CoOPd, CoOPt, iron oxide, Fe₂O₃, Fe₃O₄, or nickel oxide.

19. The method of claim 17, wherein the reducing agent is deposited before, after or both before and after the media layer.

20. The method of claim 17, wherein the reducing agent is Ta, Al, Mg, Ca, Zr, Zn, Ti, Si, C, or H₂.

21. The method of claim 17, wherein an annealing time is equal to or between 0.1 nanoseconds to 24 hours.

22. The method of claim 17, wherein an annealing temperature is equal to or greater than 100°

C.

23. The method of claim 17, wherein the BPM has a defect density of 15% or less variation in switching properties.