AP1 layer for TMR device

• US 20080212243A1
• Filed: 05/12/2008
• Published: 09/04/2008
• Est. Priority Date: 10/29/2004
• Status: Active Grant

• Current Assignee: Chyu-Jiuh Torng, Hui-Chuan Wang, Tong Zhao
• Original Assignee: Chyu-Jiuh Torng, Hui-Chuan Wang, Tong Zhao
• Inventors: Torng, Chyu-Jiuh, Wang, Hui-Chuan, Zhao, Tong
• Granted Patent: US 7,983,011 B2
• Time in Patent Office: Days
• US Class Current: 360/324.2
• 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: 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: G11B 5/3909 Arrangements using a magnetic tunnel junction
• 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 41/303 with exchange coupling adjustment of magnetic film pairs, e.g. interface modifications by reduction, oxidation
• CPC Class Codes: H10N 50/01 Manufacture or treatment
• CPC Class Codes: Y10T 29/49041 with significant slider/housing shaping or treating
• CPC Class Codes: Y10T 29/49043 Depositing magnetic layer or coating
• CPC Class Codes: Y10T 29/49044 Plural magnetic deposition layers
• CPC Class Codes: Y10T 29/49046 with etching or machining of magnetic material
• CPC Class Codes: Y10T 29/49048 Machining magnetic material [e.g., grinding, etching, polishing]
• CPC Class Codes: Y10T 29/49052 by etching

Abstract

A TMR read head with improved voltage breakdown is formed by laying down the AP1 layer as two or more layers. Each AP1 sub-layer is exposed to a low energy plasma for a short time before the next layer is deposited. This results in a smooth surface, onto which to deposit the tunneling barrier layer, with no disruption of the surface crystal structure of the completed AP1 layer.

Claims

1. An AP1 layer that is part of a magnetic tunnel junction, comprising:

an AP2 layer in the form of a first layer of soft magnetic material;

an antiferromagnetic coupling layer on said AP2 layer;

on said antiferromagnetic coupling layer, a first part of said AP1 layer in the form of a second layer of soft magnetic material having a top surface whose surface roughness is less than about 2 Angstroms.

physically contacting said smooth top surface of said second layer of soft magnetic material, a third layer of soft magnetic material, said second and third layers of soft magnetic material together constituting said AP1 layer; and

said AP1 and AP2 layers being magnetized in mutually antiparallel directions.

2. The AP1 layer described in claim 1 wherein said second layer of soft magnetic material is selected from the group consisting of CoFe, NiFe, and CoNiFe.

3. The AP1 layer described in claim 1 wherein said second layer of soft magnetic material has a thickness between about 5 and 40 Angstroms.

4. The AP1 layer described in claim 1 wherein said third layer of soft magnetic material is selected from the group consisting of CoFe, NiFe, and CoNiFe.

5. The AP1 layer described in claim 1 wherein said third layer of soft magnetic material has a thickness between about 5 and 40 Angstroms.

6. The AP1 layer described in claim 1 wherein said AP1 layer has a total thickness of between about 10 and 80 Angstroms.

7. The AP1 layer described in claim 1 wherein said second and third layers of soft magnetic material are different materials.

8. The AP1 layer described in claim 1 further comprising, on said third layer of soft magnetic material, one or more additional layers of soft magnetic material, each of whose top surfaces has a smoothness value that is less than about 2 Angstroms.

9. A TMR read head, comprising:

a seed layer on a substrate;

an antiferromagnetic layer on said seed layer;

on said antiferromagnetic layer, an AP2 layer in the form of a first layer of soft magnetic material;

an antiferromagnetic coupling layer on said AP2 layer;

on said antiferromagnetic coupling layer, a first part of an AP1 layer in the form of a second layer of soft magnetic material having a top surface whose surface roughness is less than about 2 Angstroms.

physically contacting said smooth top surface of said second layer of soft magnetic material, a third layer of soft magnetic material, said second and third layers of soft magnetic material together constituting said AP1 layer;

a non magnetic dielectric tunneling layer on said AP1 layer;

a free layer on said tunneling layer;

a capping layer on said free layer; and

said AP1 and AP2 layers being magnetized in mutually antiparallel directions.

10. The TMR read head described in claim 9 wherein said second layer of soft magnetic material is selected from the group consisting of CoFe, NiFe, and CoNiFe.

11. The TMR read head described in claim 9 wherein said second layer of soft magnetic material has a thickness between about 5 and 40 Angstroms.

12. The TMR read head described in claim 9 wherein said third layer of soft magnetic material is selected from the group consisting of CoFe, NiFe, and CoNiFe.

13. The TMR read head described in claim 9 wherein said third layer of soft magnetic material has a thickness between about 5 and 40 Angstroms.

14. The TMR read head described in claim 9 wherein said AP1 layer has a total thickness of between about 10 and 80 Angstroms.

15. The TMR read head described in claim 9 wherein said second and third layers of soft magnetic material are different materials.

16. The TMR read head described in claim 9 further comprising on said third layer of soft magnetic material, one or more additional layers of soft magnetic material, each of whose top surfaces has a smoothness value that is less than about 2 Angstroms.

17. The TMR read head described in claim 9 wherein said tunneling layer is alumina.

18. The TMR read head described in claim 9 wherein said tunneling layer has a thickness between about 5 and 8 Angstroms.