Magnetoresistive element and method of manufacturing the same

• US 9,028,909 B2
• Filed: 08/13/2012
• Issued: 05/12/2015
• Est. Priority Date: 01/30/2008
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Fukuzawa, Hideaki, Murakami, Shuichi, Yuasa, Hiromi, Fuji, Yoshihiko
• Primary Examiner(s): LOUIE, MANDY C
• Application Number:
  US13/584,293
• Publication Number:
  US 20120308728A1
• Time in Patent Office: 1,002 Days
• US Class Current: 427/127
• 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 33/04 using the flux-gate principle
• CPC Class Codes: G01R 33/093 using multilayer structures, e.g. giant magnetoresistance sensors thin magnetic films H01F10/00
• 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 5/3906 Details related to the use of magnetic thin film layers or to their effects
• CPC Class Codes: G11C 11/16 using elements in which the storage effect is based on magnetic spin effect
• CPC Class Codes: G11C 11/161 details concerning the memory cell structure, e.g. the layers of the ferromagnetic memory cell
• CPC Class Codes: G11C 11/1673 Reading or sensing circuits or methods
• CPC Class Codes: G11C 11/1675 Writing or programming circuits or methods
• CPC Class Codes: H10B 61/22 of the field-effect transistor [FET] type
• CPC Class Codes: H10N 50/01 Manufacture or treatment
• CPC Class Codes: H10N 50/10 Magnetoresistive devices
• CPC Class Codes: H10N 50/85 Magnetic active materials

Abstract

A magnetoresistive element includes a magnetoresistive film including a magnetization pinned layer, a magnetization free layer, an intermediate layer arranged between the magnetization pinned layer and the magnetization free layer, a cap layer arranged on the magnetization pinned layer or on the magnetization free layer, and a functional layer arranged in the magnetization pinned layer, in the magnetization free layer, in the interface between the magnetization pinned layer and the intermediate layer, in the interface between the intermediate layer and the magnetization free layer, or in the interface between the magnetization pinned layer or the magnetization free layer and the cap layer, and a pair of electrodes which pass a current perpendicularly to a plane of the magnetoresistive film, in which the functional layer is formed of a layer including nitrogen and a metal material containing 5 atomic % or more of Fe.

Claims

1. A method of manufacturing a magnetoresistive element comprising a magnetoresistive film, wherein the method comprises forming a functional layer disposed at an interface between a lower magnetization pinned layer and an upper magnetization pinned layer, at an interface between a lower magnetization free layer and an upper magnetization free layer, at an interface between a magnetization pinned layer and an intermediate layer, at an interface between the intermediate layer and a magnetization free layer, at an interface between the magnetization pinned layer and a cap layer, or at an interface between the magnetization free layer and the cap layer, and providing a pair of electrodes which passes a current perpendicularly to a plane of the magnetoresistive film, wherein forming the functional layer includes:

repeating consecutively two or more processes each comprising depositing a metal layer containing 5 atomic % or more of Fe and exposing the metal layer to a nitrogen atmosphere to form a nitride of an Fe-containing metal.

2. The method according to claim 1, wherein a thickness T of the layer in nanometers and a number of times N, by which processes are repeated, satisfies the following formula:

N≧

(T/0.5)×

X,

where X is a constant of 1 to 2, and T≧

1.

3. The method according to claim 1, wherein a thickness of the metal layer deposited in one process is 1 nm or less.

4. The method according to claim 1, wherein the functional layer has a crystalline orientation dispersion angle of 5 degrees or less.

5. The method according to claim 1, wherein the magnetization pinned layer or the magnetization free layer has a crystalline orientation dispersion angle of 5 degrees or less.

6. The method according to claim 1, wherein the functional layer is formed of an alloy including Fe and Co.

7. The method according to claim 1, wherein the functional layer has a thickness from 0.3 nm to 5 nm.

8. The method according to claim 1, wherein the functional layer has a Fe content of 50 atomic % or more.

9. The method according to claim 1, wherein the intermediate layer is a metal layer comprising an element selected from the group consisting of Au, Ag and Cu.

10. The method according to claim 1, wherein the intermediate layer comprises an insulating layer comprising nitrogen or oxygen and a current path penetrating the insulating layer.

11. The method according to claim 10, wherein the current path comprises an element selected from the group consisting of Au, Ag, Cu, Fe, Co and Ni.

12. The method according to claim 10, wherein the current path has a diameter of 1 nm or more and 7 nm or less.

13. The method according to claim 1, wherein the functional layer is formed of a layer comprising nitrogen;

Fe;

an element selected from the group consisting of Co and Ni; and

B, where the Fe content of a total of Fe, Co, Ni and B is 5 atomic % or more.

14. A method of manufacturing a magnetoresistive element comprising a magnetoresistive film, wherein the method comprises forming a functional layer disposed at an interface between a lower magnetization pinned layer and an upper magnetization pinned layer, at an interface between a lower magnetization free layer and an upper magnetization free layer, at an interface between a magnetization pinned layer and an intermediate layer, at an interface between the intermediate layer and a magnetization free layer, at an interface between the magnetization pinned layer and a cap layer, or at an interface between the magnetization free layer and the cap layer, and providing a pair of electrodes which passes a current perpendicularly to a plane of the magnetoresistive film, wherein forming the functional layer includes:

depositing a first metal layer containing 5 atomic % or more of Fe and exposing the first metal layer to a nitrogen atmosphere to form a lower functional layer comprising a nitride of an Fe-containing first metal; and

depositing a second metal layer, directly on the lower functional layer, containing 5 atomic % or more of Fe and exposing the second metal layer to a nitrogen atmosphere to form an upper functional layer comprising a nitride of an Fe-containing second metal, thereby forming the functional layer.

15. A method of manufacturing a magnetoresistive element comprising a magnetoresistive film, wherein the method comprises forming a magnetization pinned layer, a magnetization direction of which is substantially pinned in one direction, a magnetization free layer, a magnetization direction of which is varied depending on an external magnetic field, an intermediate layer arranged between the magnetization pinned layer and the magnetization free layer, a cap layer arranged on the magnetization pinned layer or on the magnetization free layer, and a functional layer disposed at an interface between a lower magnetization pinned layer and an upper magnetization pinned layer, at an interface between a lower magnetization free layer and an upper magnetization free layer, at an interface between the magnetization pinned layer and the intermediate layer, at an interface between the intermediate layer and the magnetization free layer, at an interface between the magnetization pinned layer and the cap layer, or at an interface between the magnetization free layer and the cap layer, and providing a pair of electrodes which passes a current perpendicularly to a plane of the magnetoresistive film, wherein forming the functional layer includes:

repeating consecutively two or more processes each comprising depositing a metal layer containing 5 atomic % or more of Fe and exposing the metal layer to a nitrogen atmosphere to form a nitride of an Fe-containing metal.