CPP type magnetic sensor or magnetic sensor using tunnel effect, and manufacturing method therefor

• US 6,826,022 B2
• Filed: 08/09/2002
• Issued: 11/30/2004
• Est. Priority Date: 08/13/2001
• Status: Expired due to Fees

• Current Assignee: TDK Corporation
• Original Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Inventors: Umetsu, Eiji
• Primary Examiner(s): CAO, ALLEN T
• Application Number:
  US10/215,693
• Publication Number:
  US 20030030948A1
• Time in Patent Office: 844 Days
• Field of Search: 360/324.12, 360/322, 360/313, 360/314, 360/324.2, 428/692, 428/326, 428/457
• US Class Current: 360/324.12
• 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: 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 2005/3996 large or giant magnetoresistive effects [GMR], e.g. as generated in spin-valve [SV] devices
• 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: Y10T 29/49052 by etching

Abstract

By forming insulating layers on two sides of a laminate, forming a free magnetic layer continuously on the laminate and the insulating layers, and placing the free magnetic layer in a single magnetic domain by an exchange bias method, reproducing output and changing rate of resistance of a CPP type magnetic sensor can be improved even when recording density is increased in the future.

Claims

1. A magnetic sensor comprising:

a laminate having a first antiferromagnetic layer, a fixed magnetic layer formed on an upper surface of the first antiferromagnetic layer, a magnetization of the fixed magnetic layer being fixed in a predetermined direction by an exchange coupling magnetic field generated between the first antiferromagnetic layer and the fixed magnetic layer, and a nonmagnetic material layer formed on an upper surface of the fixed magnetic layer;

insulating layers formed on two sides in a track width direction of the laminate;

a free magnetic layer formed continuously on an upper surface of the nonmagnetic material layer and upper surfaces of the insulating layers, a magnetization of the free magnetic layer being aligned in a direction crossing that of the fixed magnetic layer;

a second antiferromagnetic layer formed at an upper side of the free magnetic layer;

a recess portion formed in the second antiferromagnetic layer from an upper surface thereof in a direction toward the laminate at a position opposing the laminate in a thickness direction; and

electrode layers formed at a lower side of the laminate and the upper side of the second antiferromagnetic layer.

2. A magnetic sensor according to claim 1, wherein a width dimension in the track width direction of the upper surface of the laminate is at most a width dimension in the track width direction of a bottom surface of the recess portion.

3. A magnetic sensor according to claim 1, wherein the nonmagnetic material layer contains one of element Ru, Rh, Re, Os, Ir, Pt, Pd, and a mixture thereof at a higher concentration at an upper surface side of the nonmagnetic material layer than that at a lower surface side thereof.

4. A magnetic sensor according to claim 3, wherein the nonmagnetic material layer is composed of a lower layer, which is formed of one of a Cu layer, an Rh layer, an Ru layer, an Re layer, an Os layer, a Cr layer, an Ir layer, a Pt layer, a Pd layer, and a layer containing at least two elements forming the above layers, and an upper layer which is provided on the lower layer and which is formed of one of an Ru layer, an Rh layer, an Re layer, an Os layer, an Ir layer, a Pt layer, a Pd layer, and a layer containing at least two elements forming the above-mentioned layers.

5. A magnetic sensor according to claim 3, wherein the entire nonmagnetic material layer is formed of one of an Ru layer, an Rh layer, an Re layer, an Os layer, an Ir layer, a Pt layer, a Pd layer, and a layer containing at least two elements forming the above-mentioned layers.

6. A magnetic sensor according to claim 1, further comprising a nonmagnetic interlayer and a ferromagnetic layer formed on the free magnetic layer in that order, wherein the second antiferromagnetic layer is formed on the ferromagnetic layer.

7. A magnetic sensor according to claim 6, wherein the recess portion is formed to extend to a surface of the ferromagnetic layer so that the surface thereof is exposed at a bottom of the recess portion.

8. A magnetic sensor according to claim 6, wherein the recess portion is formed to extend to a surface of the nonmagnetic interlayer so that the surface thereof is exposed at a bottom of the recess portion.

9. A method for manufacturing a magnetic sensor comprising:

a step (a) of forming a laminate composed of a first antiferromagnetic layer, a fixed magnetic layer, and a nonmagnetic material layer provided in that order on a first electrode layer;

a step (b) of forming a lift-off resist layer on an upper surface of the laminate and removing two side surfaces thereof, which are not covered with the resist layer, in a track width direction;

a step (c) of forming insulating layers on two sides in the track width direction of the laminate and removing the resist layer;

a step (d) of forming a free magnetic layer continuously on the insulating layers and the nonmagnetic material layer and forming a second antiferromagnetic layer on the free magnetic layer;

a step (f) of forming a mask layer having an opening at a position opposing the laminate in a thickness direction on the second antiferromagnetic layer and excavating the second antiferromagnetic layer which is exposed in the opening to form a recess portion in the second antiferromagnetic layer; and

a step (g) of forming a second electrode layer on the second antiferromagnetic layer.

10. A method for manufacturing a magnetic sensor according to claim 9, wherein, in the step (f), a width dimension in the track width direction of a bottom surface of the recess portion is formed to be larger than a width dimension in the track width direction of the upper surface of the laminate.

11. A method for manufacturing a magnetic sensor according to claim 9, wherein, in the step (a), the nonmagnetic material layer is composed of a lower layer, which is formed of one of a Cu layer, an Rh layer, an Ru layer, an Re layer, an Os layer, a Cr layer, an Ir layer, a Pt layer, a Pd layer, and a layer containing at least two elements forming the above layers, and an upper layer which is provided on the lower layer and which is formed of one of an Ru layer, an Rh layer, an Re layer, an Os layer, an Ir layer, a Pt layer, a Pd layer, and a layer containing at least two elements forming the above-mentioned layers.

12. A method for manufacturing a magnetic sensor according to claim 9, wherein, in the step (a), the nonmagnetic material layer is formed of one of an Ru layer, an Rh layer, an Re layer, an Os layer, an Ir layer, a Pt layer, a Pd layer, and a layer containing at least two elements forming the above-mentioned layers.

13. A method for manufacturing a magnetic sensor according to claim 9, wherein, in the step (d), a nonmagnetic interlayer and a ferromagnetic layer are formed in that order on the free magnetic layer, and the second antiferromagnetic layer is then formed on the ferromagnetic layer.

14. A method for manufacturing a magnetic sensor according to claim 13, wherein, in the step (f), the second antiferromagnetic layer is excavated to expose a surface of the ferromagnetic layer.

15. A method for manufacturing a magnetic sensor according to claim 9, wherein, in the step (f), a part of the second antiferromagnetic layer is excavated.

16. A method for manufacturing a magnetic sensor according to claim 9, wherein the mask layer formed in the step (f) is formed from an inorganic material.

17. A method for manufacturing a magnetic sensor according to claim 9, further comprising, instead of the steps (d) to (g):

a step (h) of, after the free magnetic layer is formed continuously on the insulating layers and the nonmagnetic material layer, forming a nonmagnetic interlayer on the free magnetic layer;

a step (l) of forming a lift-off resist layer on the nonmagnetic interlayer at a position opposing the laminate in the thickness direction, and forming a ferromagnetic layer and a second antiferromagnetic layer in that order on each of two sides, which are not covered with the resist layer, in the track width direction of the nonmagnetic interlayer so that a recess portion is formed between the ferromagnetic layers and between the second antiferromagnetic layers; and

a step (j) of removing the resist layer.

18. A magnetic sensor comprising:

a laminate formed of a first antiferromagnetic layer, a fixed magnetic layer formed on an upper surface of the first antiferromagnetic layer, a magnetization of the fixed magnetic layer being fixed in a predetermined direction by an exchange coupling magnetic field generated between the first antiferromagnetic layer and the fixed magnetic layer, and a spacer layer which is formed on an upper surface of the fixed magnetic layer and which contains at least an insulating barrier layer;

insulating layers formed on two sides in a track width direction of the laminate;

a free magnetic layer formed continuously on an upper surface of the spacer layer and upper surfaces of the insulating layers, a magnetization of the free magnetic layer being aligned in a direction crossing that of the fixed magnetic layer;

a second antiferromagnetic layer formed at an upper side of the free magnetic layer;

a recess portion formed in the second antiferromagnetic layer from a surface thereof in a direction toward the laminate at a position opposing to the laminate in a thickness direction, a width dimension in the track width direction of a bottom surface of the recess portion being formed to be smaller than a width dimension in the track width direction of an upper surface of the laminate; and

electrode layers formed at a lower side of the laminate and at an upper side of the second antiferromagnetic layer.

19. A magnetic sensor according to claim 18, wherein the insulating barrier layer is formed of one of Al—

O, Si—

O, and Al—

Si—

O.

20. A magnetic sensor according to claim 18, wherein the spacer layer has a laminated structure composed of the insulating barrier layer and a protective layer which is provided thereon and which contains at least one selected from the group consisting of Ru, Ir, Rh, Os, Re, Pt, and Pd.

21. A magnetic sensor according to claim 18, further comprising a nonmagnetic interlayer and a ferromagnetic layer formed in that order on the free magnetic layer, wherein the second antiferromagnetic layer is formed on the ferromagnetic layer.

22. A magnetic sensor according to claim 21, wherein the recess portion is formed to extend to a surface of the ferromagnetic layer so that the surface thereof is exposed at a bottom of the recess portion.

23. A magnetic sensor according to claim 21, wherein the recess portion is formed to extend to a surface of the nonmagnetic interlayer so that the surface thereof is exposed at a bottom of the recess portion.

24. A method for manufacturing a magnetic sensor comprising:

a step (a) of forming a laminate composed of a first antiferromagnetic layer, a fixed magnetic layer, and an insulating barrier layer provided in that order on a first electrode layer;

a step (b) of forming a lift-off resist layer on an upper surface of the laminate and removing two side surfaces thereof, which are not covered with the resist layer, in a track width direction;

a step (c) of forming insulating layers on two sides in the track width direction of the laminate and removing the resist layer;

a step (d) of forming a free magnetic layer continuously on the insulating layers and the insulating barrier layer and forming a second antiferromagnetic layer on the free magnetic layer;

a step (f) of forming a mask layer having an opening at a position opposing the laminate in a thickness direction on the second antiferromagnetic layer and excavating the second antiferromagnetic layer which is exposed in the opening to form a recess portion in the second antiferromagnetic layer so that a width dimension in the track width direction of a bottom surface of the recess portion is smaller than a width dimension in the track width direction of an upper surface of the laminate; and

a step (g) of forming a second electrode layer on the second antiferromagnetic layer.

25. A method for manufacturing a magnetic sensor according to claim 24, wherein, in the step (a), the insulating barrier layer comprises an insulating material composed of one of Al—

O, Si—

O, and Al—

Si—

O.

26. A method for manufacturing a magnetic sensor according to claim 25, wherein, in the step (a), after an initial layer composed of one of Al, Si, and Al—

Si is formed on the fixed magnetic layer, the insulating barrier layer composed of one of Al—

O, Si—

O, and Al—

Si—

O is formed by oxidizing the initial layer.

27. A method for manufacturing a magnetic sensor according to claim 24, wherein, in the step (a), a protective layer composed of at least one selected from the group consisting of Ru, Ir, Rh, Os, Re, Pt, and Pd is formed on the insulating barrier layer, whereby the protective layer and the insulating barrier layer form a spacer layer.

28. A method for manufacturing a magnetic sensor according to claim 24, wherein, in the step (d), a nonmagnetic interlayer and a ferromagnetic layer are formed.

29. A method for manufacturing a magnetic sensor according to claim 28, wherein, in the step (f), the second antiferromagnetic layer is excavated to expose a surface of the ferromagnetic layer.

30. A method for manufacturing a magnetic sensor according to claim 24, wherein, in the step (f), a part of the second antiferromagnetic layer is excavated.

31. A method for manufacturing a magnetic sensor according to claim 24, wherein the mask layer formed in the step (f) is formed from an inorganic material.

32. A method for manufacturing a magnetic sensor according to claim 24, further comprising, instead of the steps (d) to (g):

a step (h) of, after the free magnetic layer is formed continuously on the insulating layers and the insulating barrier layer, forming a nonmagnetic interlayer on the free magnetic layer;

a step (i) of forming a lift-off resist layer on the nonmagnetic interlayer at a position opposing the laminate in the thickness direction, and forming ferromagnetic layers and second antiferromagnetic layers in that order on two sides, which are not covered with the resist layer, in the track width direction of the nonmagnetic interlayer so that a width dimension in the track width direction of a surface of the nonmagnetic interlayer which is exposed between the second antiferromagnetic layers is smaller than a width dimension in the track width direction of the upper surface of the laminate; and

a step (j) of removing the resist layer.