MAGNETORESISTIVE ELEMENT AND PRODUCING METHOD THEREOF

• US 20130069184A1
• Filed: 09/14/2012
• Published: 03/21/2013
• Est. Priority Date: 09/20/2011
• Status: Active Grant

• Current Assignee: Kioxia Corporation
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: AIKAWA, Hisanori, YODA, Hiroaki, KISHI, Tatsuya, IKEGAWA, Sumio, NAKAYAMA, Masahiko
• Granted Patent: US 8,878,321 B2
• Time in Patent Office: Days
• US Class Current: 257/421
• 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

Abstract

According to one embodiment, a magnetoresistive element comprises a first magnetic layer, in which a magnetization direction is variable and is perpendicular to a film surface, a tunnel barrier layer that is formed on the first magnetic layer, and a second magnetic layer that is formed on the tunnel barrier layer, a magnetization direction of the second magnetic layer being variable and being perpendicular to the film surface. The second magnetic layer comprises a body layer that constitutes an origin of perpendicular magnetic anisotropy, and an interface layer that is formed between the body layer and the tunnel barrier layer. The interface layer has a permeability higher than that of the body layer and a planar size larger than that of the body layer.

Claims

1. A magnetoresistive element comprising:

a first magnetic layer, in which a magnetization direction is variable and is perpendicular to a film surface;

a tunnel barrier layer that is formed on the first magnetic layer; and

a second magnetic layer that is formed on the tunnel barrier layer, a magnetization direction of the second magnetic layer being variable and being perpendicular to the film surface,

wherein the second magnetic layer comprises a body layer that constitutes an origin of perpendicular magnetic anisotropy, and an interface layer that is formed between the body layer and the tunnel barrier layer, the interface layer having a permeability higher than that of the body layer and a planar size larger than that of the body layer.

2. The element of claim 1, wherein a shielding layer having a permeability higher than that of the body layer is formed on a side surface of the body layer.

3. The element of claim 2, wherein the shielding layer is formed while contacting the interface layer.

4. The element of claim 2, wherein a closest distance between the interface layer and the shielding layer is less than or equal to 10 nm.

5. The element of claim 1, wherein planar shapes of the interface layer and the body layer are a circular shape, and a difference in diameter between the interface layer and the body layer ranges from 2 nm to 6 nm.

6. The element of claim 1, wherein relative permeability of the interface layer is greater than or equal to 50.

7. The element of claim 1, wherein a film thickness of the interface layer ranges from 0.3 nm to 5 nm.

8. The element of claim 2, wherein the shielding layer contains at least one of Co, Fe, and Ni, and a composition ratio thereof in the shielding layer is greater than or equal to 1%.

9. The element of claim 1, wherein the interface layer contains at least one of Co, Fe, and Ni.

10. The element of claim 1, wherein the body layer comprises an alloy or a stacked structure, which contains Co, Fe, Pt, or Pd.

11. The element of claim 2, wherein an insulating layer is formed between the body layer and the shielding layer.

12. The element of claim 4, wherein the shielding layer is formed into a tapered shape in which a film thickness increases from a lower portion side toward an upper portion side.

13. A magnetoresistive element comprising:

a first magnetic layer, in which a magnetization direction is variable and is perpendicular to a film surface;

a tunnel barrier layer that is formed on the first magnetic layer; and

a second magnetic layer that is formed on the tunnel barrier layer, a magnetization direction of the second magnetic layer being variable and being perpendicular to the film surface,

wherein the second magnetic layer comprises a body layer that constitutes an origin of perpendicular magnetic anisotropy, and an interface layer that is formed between the body layer and the tunnel barrier layer, the interface layer having a permeability higher than that of the body layer, and

a shielding layer having a permeability higher than that of the body layer is formed on a side surface of the body layer.

14. The element of claim 13, wherein the interface layer is equal to the body layer in the planar size.

15. The element of claim 13, wherein the shielding layer is formed while contacting the interface layer.

16. The element of claim 13, wherein a closest distance between the interface layer and the shielding layer is less than or equal to 10 nm.

17. The element of claim 13, wherein relative permeability of the interface layer is greater than or equal to 50.

18. The element of claim 13, wherein a film thickness of the interface layer ranges from 0.3 nm to 5 nm.

19. The element of claim 13, wherein the shielding layer contains at least one of Co, Fe, and Ni, and a composition ratio thereof in the shielding layer is greater than or equal to 1%.

20. A magnetoresistive element producing method comprising:

forming a first magnetic layer, in which a magnetization direction is variable and is perpendicular to a film surface;

forming a tunnel barrier layer on the first magnetic layer;

forming an interface layer on the tunnel barrier layer, a magnetization direction of the interface layer being variable and being perpendicular to the film surface;

forming a body layer on the interface layer, a magnetization direction of the body layer being variable and being perpendicular to the film surface, the body layer constituting an origin of perpendicular magnetic anisotropy, the body layer having a permeability lower than that of the interface layer;

forming a hard mask on the body layer;

etching the body layer with the hard mask as a mask;

forming an insulating layer on a side surface of the body layer; and

etching the interface layer, the tunnel barrier layer, and the first magnetic layer with the insulating layer as a mask such that a planar size of the interface layer is larger than that of the body layer,

wherein a shielding layer having a permeability higher than that of the body layer is formed on the side surface of the body layer by performing physical etching in the etching the interface layer, the tunnel barrier layer, and the first magnetic layer.