Tunneling magnetoresistive element and method of manufacturing the same

• US 20020006020A1
• Filed: 07/13/2001
• Published: 01/17/2002
• Est. Priority Date: 07/17/2000
• Status: Active Grant

• Current Assignee: TDK Corporation
• Original Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Inventors: Hasegawa, Naoya
• Granted Patent: US 6,751,073 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 2005/3996 large or giant magnetoresistive effects [GMR], e.g. as generated in spin-valve [SV] devices
• CPC Class Codes: G11B 5/3116 Shaping of layers, poles or gaps for improving the form of the electrical signal transduced, e.g. for shielding, contour effect, equalizing, side flux fringing, cross talk reduction between heads or between heads and information tracks G11B5/3113, G11B5/245 take precedence
• 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 10/3254 the spacer being semiconducting or insulating, e.g. for spin tunnel junction [STJ]
• CPC Class Codes: H01F 10/3268 the exchange coupling being asymmetric, e.g. by use of additional pinning, by using antiferromagnetic or ferromagnetic coupling interface, i.e. so-called spin-valve [SV] structure, e.g. NiFe/Cu/NiFe/FeMn
• 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 29/49039 with dual gap materials
• 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

Insulating layers are formed on both sides of a multilayer film, and bias layers are formed in contact with at least portions of both end surfaces of a free magnetic layer. The bias layers are formed so as not to extend to the upper surface of the multilayer film. In this construction, a sensing current from electrode layers appropriately flows through the multilayer film, and a bias magnetic field can be supplied to the free magnetic layer from the bias layers through both side surfaces of the free magnetic layer. Furthermore, the magnetic domain structure of the free magnetic layer can be stabilized to permit an attempt to decrease instability of the reproduced waveform and Barkhausen noise.

Claims

1. A tunneling magnetoresistive element comprising a multilayer film comprising an antiferromagnetic layer, a pinned magnetic layer formed in contact with the antiferromagnetic layer so that the magnetization direction is pinned by an exchange coupling magnetic field with the antiferromagnetic layer, and a free magnetic layer formed on the pined magnetic layer with an insulating barrier layer provided therebetween, electrode layers formed above and below the multilayer film, insulating layers formed on both sides of the multilayer film in the track width direction, and domain control layers respectively formed on the insulating layers so as to contact at least portions of both end surfaces of the free magnetic layer, for orienting the magnetization direction of the free magnetic layer in a direction crossing the magnetization direction of the pinned magnetic layer;

wherein the domain control layers are formed so as not to extend to the upper surface of the multilayer film.

2. A tunneling magnetoresistive element according to claim 1, wherein an under laying layer is formed below each of the domain control layers, for controlling crystal orientation of the domain control layers.

3. A tunneling magnetoresistive element according to claim 1, wherein each of the domain control layers comprises a hard magnetic material.

4. A tunneling magnetoresistive element according to claim 1, wherein each of the domain control layers comprises a laminated film of a ferromagnetic layer and a second antiferromagnetic layer, the ferromagnetic layers being in contact with at least portions of both side surfaces of the free magnetic layer.

5. A tunneling magnetoresistive element according to claim 1, wherein each of the insulating layers comprises an antiferromagnetic insulating layer exhibiting an antiferromagnetic property, and each of the domain control layers comprises a ferromagnetic layer.

6. A tunneling magnetoresistive element according to claim 4, wherein the second antiferromagnetic layer is made of α

-Fe₂O₃.

7. A tunneling magnetoresistive element according to claim 5, wherein the antiferromagnetic insulating layer is made of α

-Fe₂O₃.

8. A tunneling magnetoresistive element comprising a multilayer film comprising an antiferromagnetic layer, a pinned magnetic layer formed in contact with the antiferromagnetic layer so that the magnetization direction is pinned by an exchange coupling magnetic field with the antiferromagnetic layer, a free magnetic layer formed on the pined magnetic layer with an insulating barrier layer provided therebetween, electrode layers formed above and below the multilayer film, insulating layers formed on both sides of the multilayer film in the track width direction, and domain control layers formed on the insulating layers so as to contact portions of both side surfaces of at least the free magnetic layer, for orienting the magnetization direction of the free magnetic layer in a direction crossing the magnetization direction of the pinned magnetic layer;

wherein the multilayer film comprises a central sensitive zone having excellent reproducing sensitivity so that a magnetoresistive effect can be substantially exhibited, and dead zones formed on both sides of the sensitive zone and having low reproducing sensitivity so that the magnetoresistive effect cannot be substantially exhibited; and

the domain control layers are formed so as to extend on the dead zones of the multilayer film.

9. A tunneling magnetoresistive element according to claim 8, wherein an under laying layer is formed below each of the domain control layers, for controlling crystal orientation of the domain control layers.

10. A tunneling magnetoresistive element according to claim 8, wherein each of the domain control layers comprises a hard magnetic material.

11. A tunneling magnetoresistive element according to claim 8, wherein each of the domain control layers comprises a laminated film of a ferromagnetic layer and a second antiferromagnetic layer, the ferromagnetic layers being in contact with at least portions of both side surfaces of the free magnetic layer.

12. A tunneling magnetoresistive element according to claim 8, wherein each of the insulating layers comprises an antiferromagnetic insulating layer exhibiting an antiferromagnetic property, and each of the domain control layers comprises a ferromagnetic layer.

13. A tunneling magnetoresistive element according to claim 11, wherein the second antiferromagnetic layer is made of α

-Fe₂O₃.

14. A tunneling magnetoresistive element according to claim 12, wherein the antiferromagnetic insulating layer is made of α

-Fe₂o₃.

15. A tunneling magnetoresistive element comprising a multilayer film comprising a free magnetic layer, a pinned magnetic layer formed on the free magnetic layer with an insulating barrier layer provided therebetween, and an antiferromagnetic layer formed on the pinned magnetic layer, for pinning the magnetization direction of the pinned magnetic layer by an exchange coupling magnetic field, electrode layers formed above and below the multilayer film, domain control layers formed on both sides of the multilayer film in the track width direction so as to contact at least portions of both side surfaces of the free magnetic layer, for orienting the magnetization direction of the free magnetic layer in a direction crossing the magnetization direction of the pinned magnetic layer, and insulating layers formed on the domain control layers;

wherein the insulating layers are formed so as not to extend to the upper surface of the multilayer film.

16. A tunneling magnetoresistive element according to claim 15, wherein an under laying layer is formed below each of the domain control layers, for controlling crystal orientation of the domain control layers.

17. A tunneling magnetoresistive element according to claim 15, wherein each of the domain control layers comprises a hard magnetic material.

18. A tunneling magnetoresistive element according to claim 15, wherein each of the domain control layers comprises a laminated film of a ferromagnetic layer and a second antiferromagnetic layer, the ferromagnetic layers being in contact with at least portions of both side surfaces of the free magnetic layer.

19. A tunneling magnetoresistive element according to claim 15, wherein each of the insulating layers comprises an antiferromagnetic insulating layer exhibiting an antiferromagnetic property, and each of the domain control layers comprises a ferromagnetic layer.

20. A tunneling magnetoresistive element according to claim 18, wherein the second antiferromagnetic layer is made of α

-Fe₂O₃.

21. A tunneling magnetoresistive element according to claim 19, wherein the antiferromagnetic insulating layer is made of α

-Fe₂O₃.

28. A tunneling magnetoresistive element according to claim 16, wherein the antiferromagnetic insulating layer is made of α

-Fe₂O₃.

22. A tunneling magnetoresistive element comprising a multilayer film comprising a free magnetic layer, a pinned magnetic layer formed on the free magnetic layer with an insulating barrier layer provided therebetween, and an antiferromagnetic layer formed on the pinned magnetic layer, for pinning the magnetization direction of the pinned magnetic layer by an exchange coupling magnetic field, electrode layers formed above and below the multilayer film, domain control layers formed on both sides of the multilayer film in the track width direction so as to contact portions of both side surfaces of at least the free magnetic layer, for orienting the magnetization direction of the free magnetic layer in a direction crossing the magnetization direction of the pinned magnetic layer, and insulating layers formed on the domain control layers;

wherein the multilayer film comprises a central sensitive zone having excellent reproducing sensitivity so that a magnetoresistive effect can be substantially exhibited, and dead zones formed on both sides of the sensitive zone and having poor reproduction sensitivity so that the magnetoresistive effect cannot be substantially exhibited; and

the insulating layers are formed so as to extend on the dead zones of the multilayer film.

23. A tunneling magnetoresistive element according to claim 22, wherein an under laying layer is formed below each of the domain control layers, for controlling crystal orientation of the domain control layers.

24. A tunneling magnetoresistive element according to claim 22, wherein each of the domain control layers comprise a hard magnetic material.

25. A tunneling magnetoresistive element according to claim 22, wherein each of the domain control layers comprises a laminated film of a ferromagnetic layer and a second antiferromagnetic layer, the ferromagnetic layers being in contact with at least portions of both side surfaces of the free magnetic layer.

26. A tunneling magnetoresistive element according to claim 22, wherein each of the insulating layers comprises an antiferromagnetic insulating layer exhibiting an antiferromagnetic property, and each of the domain control layers comprises a ferromagnetic layer.

27. A tunneling magnetoresistive element according to claim 25, wherein the second antiferromagnetic layer is made of α

-Fe₂O₃.

29. A method of manufacturing a tunneling magnetoresistive element comprising:

(a) the step of forming an electrode layer on a substrate, and then laminating an antiferromagnetic layer, a pinned magnetic layer in which magnetization is pinned in a predetermined direction by an exchange coupling magnetic field with the antiferromagnetic layer, an insulating barrier layer, and a free magnetic layer in turn from the bottom to form a multilayer film;

(b) the step of forming, on the multilayer film, a lift-off resist layer having a notched portion formed on the lower side thereof;

(c) the step of removing both sides of the mulitlayer film leaving at least a portion of the multilayer film below the resist layer;

(d) the step of forming insulating layers on both sides of the multilayer film so that the multilayer film-side ends of the upper surfaces of the insulating layers are lower than both ends of the upper surface of the free magnetic layer;

(e) the step of forming domain control layers on the insulating layers by sputtering obliquely to the substrate so that the domain control layers contact both ends of the free magnetic layer, and the multilayer film-side ends of the domain control layers coincide with the both ends of the top of the multilayer film; and

(f) the step of removing the resist layer, and forming an electrode layer on the multilayer film and the domain control layers.

30. A method of manufacturing a tunneling magnetoresistive element according to claim 29, wherein an under laying layer is formed below each of the domain control layers, for controlling crystal orientation of the domain control layers.

31. A method of manufacturing a tunneling magnetoresistive element according to claim 29, wherein in the step (d), the insulating layers or the domain control layers are formed by sputtering vertically to the substrate.

32. A method of manufacturing a tunneling magnetoresistive element according to claim 29, wherein each of the domain control layers comprises a hard magnetic material.

33. A method of manufacturing a tunneling magnetoresistive element according to claim 29, wherein each of the domain control layers comprises a laminated film of a ferromagnetic layer and a second antiferromagnetic layer, the ferromagnetic layers being in contact with at least portions of both side surfaces of the free magnetic layer.

34. A method of manufacturing a tunneling magnetoresistive element according to claim 29, wherein each of the insulating layers comprises an antiferromagnetic insulating layer exhibiting an antiferromagnetic property, and each of the domain control layers comprises a ferromagnetic layer.

35. A method of manufacturing a tunneling magnetoresistive element according to claim 29, wherein the second antiferromagnetic layer is made of α

-Fe₂O₃.

36. A method of manufacturing a tunneling magnetoresistive element according to claim 33, wherein the antiferromagnetic insulating layer exhibiting antiferromagnetism is made of α

-Fe₂O₃.

37. A method of manufacturing a tunneling magnetoresistive element comprising:

(g) the step of forming an electrode layer on a substrate, and then laminating an antiferromagnetic layer, a pinned magnetic layer in which magnetization is pinned in a predetermined direction by an exchange coupling magnetic field with the antiferromagnetic layer, an insulating barrier layer and a free magnetic layer in turn from the bottom to form a multilayer film;

(h) the step of forming, on a sensitive zone of the multilayer film, a lift-off resist layer having a notched portion formed on the lower side thereof;

(i) the step of removing both sides of the multilayer film leaving at least a portion of the multilayer film below the resist layer;

(j) the step of forming insulating layers on both sides of the multilayer film so that the multilayer film-side ends of the upper surfaces of the insulating layers are lower than both ends of the upper surface of the free magnetic layer;

(k) the step of forming domain control layers on the insulating layers by sputtering obliquely to the substrate so that the domain control layers contact both ends of the free magnetic layer, and extend on dead zones of the multilayer film; and

(l) the step of removing the resist layer, and forming an electrode layer on the multilayer film and the domain control layers.

38. A method of manufacturing a tunneling magnetoresistive element according to claim 37, wherein an under laying layer is formed below each of the domain control layers, for controlling crystal orientation of the domain control layers.

39. A method of manufacturing a tunneling magnetoresistive element according to claim 37, wherein in the step (j), the insulating layers or the domain control layers are formed by sputtering vertically to the substrate.

40. A method of manufacturing a tunneling magnetoresistive element according to claim 37, wherein each of the domain control layers comprises a hard magnetic material.

41. A method of manufacturing a tunneling magnetoresistive element according to claim 37, wherein each of the domain control layers comprises a laminated film of a ferromagnetic layer and a second antiferromagnetic layer, the ferromagnetic layers being in contact with at least portions of both side surfaces of the free magnetic layer.

42. A method of manufacturing a tunneling magnetoresistive element according to claim 37, wherein each of the insulating layers comprises an antiferromagnetic insulating layer exhibiting an antiferromagnetic property, and each of the domain control layers comprises a ferromagnetic layer.

43. A method of manufacturing a tunneling magnetoresistive element according to claim 41, wherein the second antiferromagnetic layer is made of α

-Fe₂O₃.

44. A method of manufacturing a tunneling magnetoresistive element according to claim 42, wherein the antiferromagnetic insulating layer exhibiting antiferromagnetism is made of α

-Fe₂O₃.

45. A method of manufacturing a tunneling magnetoresistive element comprising:

(m) the step of forming an electrode layer on a substrate, and then laminating a free magnetic layer, an insulating barrier layer, a pinned magnetic layer, and an antiferromagnetic layer for pinning magnetization of the pinned magnetic layer in a predetermined direction by an exchange coupling magnetic field in turn from the bottom to form a multilayer film;

(n) the step of forming, on the multilayer film, a lift-off resist layer having a notched portion formed on the lower side thereof;

(o) the step of removing both sides of the multilayer film leaving a portion of the multilayer film below the resist layer;

(p) the step of forming domain control layers on both sides of the multilayer film so that the multilayer film-side ends contact at least portions of both ends of the free magnetic layer;

(q) the step of forming insulating layers on the domain control layers by sputtering obliquely to the multilayer film so that the multilayer film-side ends of the upper surfaces of the insulating layers coincide with both ends of the upper surface of the multilayer film; and

(r) the step of removing the resist layer, and forming an electrode layer on the multilayer film and the insulating layers.

46. A method of manufacturing a tunneling magnetoresistive element according to claim 45, wherein an under laying layer is formed below each of the domain control layers, for controlling crystal orientation of the domain control layers.

47. A method of manufacturing a tunneling magnetoresistive element according to claim 45, wherein in the step (p), the insulating layers or the domain control layers are formed by sputtering vertically to the substrate.

48. A method of manufacturing a tunneling magnetoresistive element according to claim 45, wherein each of the domain control layers comprises a hard magnetic material.

49. A method of manufacturing a tunneling magnetoresistive element according to claim 45, wherein each of the domain control layers comprises a laminated film of a ferromagnetic layer and a second antiferromagnetic layer, the ferromagnetic layers being in contact with at least portions of both side surfaces of the free magnetic layer.

50. A method of manufacturing a tunneling magnetoresistive element according to claim 45, wherein each of the insulating layers comprises an antiferromagnetic insulating layer exhibiting an antiferromagnetic property, and each of the domain control layers comprises a ferromagnetic layer.

51. A method of manufacturing a tunneling magnetoresistive element according to claim 49, wherein the second antiferromagnetic layer is made of α

-Fe₂O₃.

52. A method of manufacturing a tunneling magnetoresistive element according to claim 50, wherein the antiferromagnetic insulating layer exhibiting antiferromagnetism is made of α

-Fe₂O₃.

53. A method of manufacturing a tunneling magnetoresistive element comprising:

(s) the step of forming an electrode layer on a substrate, and then laminating a free magnetic layer, an insulating barrier layer, a pinned magnetic layer, and an antiferromagnetic layer for pinning magnetization of the pinned magnetic layer in a predetermined direction by an exchange coupling magnetic field in turn from the bottom to form a multilayer film;

(t) the step of forming, on a sensitive zone of the multilayer film, a lift-off resist layer having a notched portion formed on the lower side thereof;

(u) the step of removing both sides of the multilayer film leaving at least a portion of the multilayer film below the resist layer;

(v) the step of forming domain control layers on both sides of the multilayer film so that the multilayer film-side ends contact at least portions of both ends of the free magnetic layer;

(w) the step of forming insulating layers on the domain control layers by sputtering obliquely to the multilayer film so that the insulating layers extend on dead zones of the multilayer film; and

(x) the step of removing the resist layer, and forming an electrode layer on the multilayer film and the insulating layers.

54. A method of manufacturing a tunneling magnetoresistive element according to claim 53, wherein an under laying layer is formed below each of the domain control layers, for controlling crystal orientation of the domain control layers.

55. A method of manufacturing a tunneling magnetoresistive element according to claim 53, wherein in the step (v), the insulating layers or the domain control layers are formed by sputtering vertically to the substrate.

56. A method of manufacturing a tunneling magnetoresistive element according to claim 53, wherein each of the domain control layers comprises a hard magnetic material.

57. A method of manufacturing a tunneling magnetoresistive element according to claim 53, wherein each of the domain control layers comprises a laminated film of a ferromagnetic layer and a second antiferromagnetic layer, the ferromagnetic layers being in contact with at least portions of both side surfaces of the free magnetic layer.

58. A method of manufacturing a tunneling magnetoresistive element according to claim 53, wherein each of the insulating layers comprises an antiferromagnetic insulating layer exhibiting an antiferromagnetic property, and each of the domain control layers comprises a ferromagnetic layer.

59. A method of manufacturing a tunneling magnetoresistive element according to claim 57, wherein the second antiferromagnetic layer is made of α

-Fe₂O₃.

60. A method of manufacturing a tunneling magnetoresistive element according to claim 58, wherein the antiferromagnetic insulating layer exhibiting antiferromagnetism is made of α

-Fe₂O ₃.