Methods for manufacturing a magnetoresistive structure utilizing heating and cooling

• US 9,093,639 B2
• Filed: 02/21/2012
• Issued: 07/28/2015
• Est. Priority Date: 02/21/2012
• Status: Active Grant

• Current Assignee: Western Digital Technologies Incorporated (Western Digital Corporation)
• Original Assignee: Western Digital Corporation
• Inventors: Kaiser, Christian, Leng, Qunwen, Pakala, Mahendra
• Primary Examiner(s): Cleveland, Michael
• Assistant Examiner(s): TADAYYON ESLAMI, TABASSOM
• Application Number:
  US13/401,164
• Publication Number:
  US 20130216702A1
• Time in Patent Office: 1,253 Days
• Field of Search: 428/811, 428/811.3, 428/811.1, 360/324, 360/342.2, 360/328, 257/421
• US Class Current: 1/1
• CPC Class Codes: G01R 33/093 using multilayer structures, e.g. giant magnetoresistance sensors thin magnetic films H01F10/00
• CPC Class Codes: G01R 33/098 comprising tunnel junctions, e.g. tunnel magnetoresistance sensors
• CPC Class Codes: G11B 5/3163 Fabrication methods or processes specially adapted for a particular head structure, e.g. using base layers for electroplating, using functional layers for masking, using energy or particle beams for shaping the structure or modifying the properties of the basic layers
• CPC Class Codes: G11B 5/3909 Arrangements using a magnetic tunnel junction
• CPC Class Codes: H01F 10/3259 Spin-exchange-coupled multilayers comprising at least a nanooxide layer [NOL], e.g. with a NOL spacer
• CPC Class Codes: H01F 10/3272 by use of anti-parallel coupled [APC] ferromagnetic layers, e.g. artificial ferrimagnets [AFI], artificial [AAF] or synthetic [SAF] anti-ferromagnets
• CPC Class Codes: H01F 41/307 insulating or semiconductive spacer
• CPC Class Codes: H10N 50/01 Manufacture or treatment

Abstract

This invention describes a novel tunnel magnetoresistive (TMR) deposition process that can enhance the signal-to-noise ratio (SNR) of a TMR reader. A method of manufacturing a tunnel magnetoresistive sensor includes providing a substrate; forming a first portion of a magnetic tunnel junction (MTJ) structure on the substrate; forming a second portion of the MTJ structure on the substrate; forming a tunnel barrier layer of the MTJ structure between the first portion and the second portion; heating the first portion of the MTJ structure before forming the tunnel barrier layer or after forming at least a portion of the tunnel barrier layer; and cooling the tunnel barrier layer.

Claims

1. A method for manufacturing a tunnel magnetoresistive (TMR) structure, the method comprising:

forming a reference layer on a substrate;

forming a tunnel barrier layer on the substrate;

forming a free layer on the substrate;

heating the TMR structure after forming at least the reference layer and at least a portion of the tunnel barrier layer; and

cryogenically cooling, after the heating, the TMR structure after forming the tunnel barrier layer.

2. The method of claim 1, wherein the tunnel barrier layer is positioned between the reference layer and the free layer.

3. The method of claim 1, wherein the reference layer is positioned between the substrate and the tunnel barrier layer.

4. The method of claim 1, wherein the free layer is positioned between the substrate and the tunnel barrier layer.

5. The method of claim 1, wherein the cryogenically cooling the TMR structure comprises cooling the TMR structure after a portion of the free layer is formed.

6. The method of claim 1, wherein the cryogenically cooling the TMR structure comprises cooling the TMR structure before the free layer is formed.

7. The method of claim 1, wherein the tunnel barrier layer comprises an MgO layer.

8. The method of claim 1, further comprising annealing the TMR structure in a vacuum.

9. The method of claim 1,

wherein the heating the TMR structure comprises heating the TMR structure from a first temperature to a second temperature, and

wherein the cryogenically cooling the TMR structure comprises cooling the TMR structure to a third temperature that is lower than the first temperature.

10. The method of claim 9, wherein the second temperature is between about 50°

C. and about 400°

C., inclusive.

11. The method of claim 10, wherein the second temperature is between about 100°

C. and about 300°

C., inclusive.

12. The method of claim 9, wherein the heating the TMR structure comprises heating the TMR structure for a heating time period between about one minute and about fifty minutes, inclusive.

13. The method of claim 12, wherein the heating time period is between about five minutes and about fifteen minutes, inclusive.

14. The method of claim 9, wherein the third temperature is between about −

223°

C. and about 20°

C., inclusive.

15. The method of claim 14, wherein the third temperature is between about −

173°

C. and about 0°

C., inclusive.

16. The method of claim 9, wherein the cryogenically cooling the TMR structure comprises cooling the TMR structure for a cooling time period between about five minutes and about sixty minutes, inclusive.

17. The method of claim 16, wherein the cooling time period is between about ten minutes and about thirty minutes, inclusive.

18. The method of claim 1, further comprising forming an interlayer on the tunnel barrier layer.

19. The method of claim 18, wherein the cryogenically cooling the TMR structure comprises cooling the TMR structure before forming the interlayer.

20. The method of claim 18, wherein the cryogenically cooling the TMR structure comprises cooling the TMR structure after forming the interlayer and prior to forming the free layer.

21. The method of claim 18,

wherein the heating the TMR structure comprises heating the TMR structure before forming the interlayer, and

wherein the cryogenically cooling the TMR structure comprises cooling the TMR structure after forming the interlayer, prior to forming the free layer.

22. The method of claim 18, wherein the interlayer comprises a material selected from the group consisting of Mg, Zn, Al, AlSi, Ca, and Si.

23. The method of claim 1, wherein the reference layer comprises:

a seed layer on the substrate;

a pinning layer on the seed layer; and

a pinned layer on the pinning layer.

24. The method of claim 23, further comprising forming a cap layer on the free layer.

25. A method of manufacturing a tunnel magnetoresistive sensor, the method comprising:

providing a substrate;

forming a first portion of a magnetic tunnel junction (MTJ) structure on the substrate;

forming a second portion of the MTJ structure on the substrate;

forming a tunnel barrier layer of the MTJ structure between the first portion and the second portion;

heating the first portion of the MTJ structure after forming at least a portion of the tunnel barrier layer; and

cryogenically cooling, after the heating, the MTJ structure after forming the tunnel barrier layer.

26. The method of claim 25, further comprising forming an interlayer on the tunnel barrier layer, wherein the cryogenically cooling the tunnel barrier layer comprises cryogenically cooling the tunnel barrier layer before or after forming the interlayer.

27. The method of claim 26, wherein the interlayer comprises a material selected from the group consisting of Mg, Zn, Al, AlSi, CA, and Si.

28. The method of claim 26,

wherein the first portion of the MTJ structure comprises a reference layer,

wherein the second portion of the MTJ structure comprises a free layer, and

wherein the cryogenically cooling the tunnel barrier layer comprises cryogenically cooling the tunnel barrier layer after forming a portion of the free layer or a portion of the reference layer.

29. The method of claim 26,

wherein the first portion of the MTJ structure comprises a free layer,

wherein the second portion of the MTJ structure comprises a reference layer, and

wherein the cryogenically cooling the tunnel barrier layer comprises cryogenically cooling the first portion before forming the reference layer.

30. A method of manufacturing a magnetic tunnel junction (MTJ) head for a magnetic storage device, the method comprising:

providing a substrate;

forming a first portion of the MTJ head on the substrate;

forming a second portion of the MTJ head on the substrate;

forming a tunnel barrier layer of the MTJ head between the first portion and the second portion;

heating the first portion of the MTJ head after forming at least a portion of the tunnel barrier layer; and

cryogenically cooling, after the heating, the MTJ head after forming the tunnel barrier layer.