FeTa nano-oxide layer as a capping layer for enhancement of giant magnetoresistance in bottom spin valve structures

• US 6,773,515 B2
• Filed: 01/16/2002
• Issued: 08/10/2004
• Est. Priority Date: 01/16/2002
• Status: Expired due to Fees

• Current Assignee: Headway Technologies Incorporated (TDK Corporation)
• Original Assignee: Headway Technologies Incorporated (TDK Corporation)
• Inventors: Ju, Kochan, Li, Min, Noguchi, Kiyoshi, Horng, Cheng T., Sano, Masashi, Liao, Simon H.
• Primary Examiner(s): Oltmans, Andrew L.
• Application Number:
  US10/050,644
• Publication Number:
  US 20030133232A1
• Time in Patent Office: 937 Days
• Field of Search: 148/240, 148/281, 148/284, 296/031.4, 296/030.8, 296/031.5, 360/324.1, 360/324.2, 360/324.11, 360/324.12
• US Class Current: 148/240
• CPC Class Codes: B32B 15/01 all layers being exclusively metallic making layered metal workpieces by pressure cladding B23K20/22; making coatings with a metallic material characterised by its composition C23C30/00
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 25/00 Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: C22C 38/10 containing cobalt
• CPC Class Codes: C22C 38/12 containing tungsten, tantalum, molybdenum, vanadium, or niobium
• CPC Class Codes: G01R 33/093 using multilayer structures, e.g. giant magnetoresistance sensors thin magnetic films H01F10/00
• 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 5/3903 using magnetic thin film layers or their effects, the films being part of integrated structures
• 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 41/302 for applying spin-exchange-coupled multilayers, e.g. nanostructured superlattices spin-exchange-coupled multilayers H01F10/32
• CPC Class Codes: H10N 50/01 Manufacture or treatment
• CPC Class Codes: H10N 50/10 Magnetoresistive devices
• CPC Class Codes: Y10T 29/49034 Treating to affect magnetic properties
• CPC Class Codes: Y10T 29/49044 Plural magnetic deposition layers
• CPC Class Codes: Y10T 29/49046 with etching or machining of magnetic material

Abstract

A method for forming an NiCr seed layer based bottom spin valve sensor element having a synthetic antiferromagnet pinned (SyAP) layer and a capping layer comprising either a single specularly reflecting nano-oxide layer (NOL) or a bi-layer comprising a non-metallic layer and a specularly reflecting nano-oxide layer and the sensor element so formed. The method of producing these sensor elements provides elements having higher GMR ratios and lower resistances than elements of the prior art.

Claims

1. A method for forming a bottom spin valve magnetorestive sensor element comprising:

providing a substrate;

forming on the substrate a magnetoresistive-property-enhancing seed layer;

forming on said seed layer a pinning layer of antiferromagnetic material;

forming on said pinning layer a synthetic antiferromagnetic pinned (SyAP) layer, said formation further comprising;

forming on said pinning layer a second antiparallel (AP2) pinned layer of ferromagnetic material;

forming on said second antiparallel (AP2) pinned layer a non-magnetic coupling layer; and

forming on said non-magnetic coupling layer a first antiparallel (AP1) pinned layer to complete said SyAP layer;

forming on said first antiparallel (AP1) layer of said SyAP layer a non-magnetic spacer layer;

forming on said non-magnetic spacer layer a ferromagnetic free layer;

forming on said ferromagnetic free layer a double-layer capping layer, said capping layer comprising a first layer of non-magnetic material on which is formed a second layer of the specularly reflecting material oxidized FeTa, oxidized Fe or oxidized (Fe₆₅Co₃₅)₉₇V₃;

thermally annealing said sensor element at a prescribed succession of temperatures in the presence of a corresponding sequence of external magnetic fields, establishing, thereby, the magnetizations of said free and said pinned magnetic layers.

2. The method of claim 1 wherein the non-magnetic material layer of the capping layer is a layer of non-magnetic material chosen from the group consisting of Cu, Ag, Au, Rh and Ru.

3. The method of claim 2 wherein the non-magnetic material layer of the capping layer is a layer of Cu formed to a thickness of between approximately 0 and 20 angstroms.

4. The method of claim 1 wherein the specularly reflecting layer of the capping layer is a layer of FeTaO formed to a thickness of between approximately 5 and 40 angstroms.

5. The method of claim 4 wherein the specularly reflecting layer of FeTaO is formed by an oxidation process applied to a layer of FeTa deposited on said non-magnetic material layer to a thickness of between approximately 3 and 30 angstroms.

6. The method of claim 5 wherein said layer of deposited FeTa is a layer which is approximately 95% Fe by number of atoms and approximately 5% Ta by number of atoms.

7. The method of claim 6 wherein said oxidation process is carried out in a PM5 TIM module in which there is supplied molecular oxygen at a flow rate of between approximately 5 and 50 sccm, a pressure of between approximately 0.05 and 0.5 mTorr for a time duration of between approximately 9 and 11 seconds, but where approximately 10 seconds is preferred.

8. The method of claim 1 wherein said specularly reflecting capping layer of oxidized Fe or oxidized (Fe₆₅Co₃₅)₉₇V₃ is formed to a thickness of between approximately 5 and 40 angstroms.

9. The method of claim 8 wherein said oxidation process is carried out in a PM5 TIM module in which there is supplied molecular oxygen at a flow rate of between approximately 5 and 50 sccm, a pressure of between approximately 0.05 and 0.5 mTorr for a time duration of between approximately 9 and 11 seconds, but where approximately 10 seconds is preferred.

10. A method for forming a bottom spin valve magnetorestive sensor element comprising:

providing a substrate;

forming on the substrate a magnetoresistive-property-enhancing seed layer;

forming on said seed layer a pinning layer of antiferromagnetic material;

forming on said pinning layer a synthetic antiferromagnetic pinned (SyAP) layer, said formation further comprising;

forming on said pinning layer a second antiparallel (AP2) pinned layer of ferromagnetic material;

forming on said second antiparallel (AP2) pinned layer a non-magnetic coupling layer; and

forming on said non-magnetic coupling layer a first antiparallel (AP1) pinned layer to complete said SyAP layer;

forming on said first antiparallel (AP1) layer of said SyAP layer a non-magnetic spacer layer;

forming on said non-magnetic spacer layer a ferromagnetic free layer;

forming on said ferromagnetic free layer a capping layer of the specularly reflecting material oxidized FeTa;

thermally annealing said sensor element at a prescribed succession of temperatures in the presence of a corresponding sequence of external magnetic fields, establishing, thereby, the magnetizations of said free and said pinned magnetic layers.

11. The method of claim 10 wherein said specularly reflecting capping layer is a layer of FeTaO formed to a thickness of between approximately 5 and 40 angstroms.