Magnetoresistive stack and method of fabricating same

Patent metadata

Field	Value
Publication number	US-10199574-B2
Application number	US-201815941153-A
Country	US
Kind code	B2
Filing date	Mar 30, 2018
Priority date	Jun 10, 2011
Publication date	Feb 5, 2019
Grant date	Feb 5, 2019

Abstract

A magnetoresistive element (e.g., a spin-torque magnetoresistive memory element) includes a fixed magnetic layer, a free magnetic layer, having a high-iron alloy interface region located along a surface of the free magnetic layer, wherein the high-iron alloy interface region has at least 50% iron by atomic composition, and a first dielectric, disposed between the fixed magnetic layer and the free magnetic layer. The magnetoresistive element further includes a second dielectric, having a first surface that is in contact with the surface of the free magnetic layer, and an electrode, disposed between the second dielectric and a conductor. The electrode includes: (i) a non-ferromagnetic portion having a surface that is in contact with a second surface of the second dielectric, and (ii) a second portion having at least one ferromagnetic material disposed between the non-ferromagnetic portion of the electrode and the conductor.

First claim

What is claimed is:

1. A magnetoresistive memory element, comprising:
a first fixed magnetic layer;
a first dielectric layer having a first surface and a second surface, the first dielectric layer juxtaposed the first fixed magnetic layer along the first surface of the first dielectric layer;
a second dielectric layer having a first surface and a second surface;
a second fixed magnetic layer juxtaposed the second dielectric layer along the first surface of the second dielectric layer; and
a free magnetic layer, disposed between the first and second dielectric layers, having a first surface in contact with the second surface of the first dielectric layer and a second surface in contact with the second surface of the second dielectric layer, wherein the free magnetic layer includes:
a first high-iron interface region located along the first surface of the free magnetic layer, wherein the first high-iron interface region has at least 50% iron by atomic composition,
a first layer of ferromagnetic material adjacent to the first high-iron interface region, the first high-iron interface region disposed between the first layer of ferromagnetic material and the first surface of the free magnetic layer,
a second layer of ferromagnetic material disposed between the first layer of ferromagnetic material and the second surface of the free magnetic layer, and
a first insertion layer located between the first layer of ferromagnetic material and the second layer of ferromagnetic material, wherein the first insertion layer (i) includes a non-ferromagnetic transition metal and (ii) does not break direct exchange coupling between the first layer of ferromagnetic material and the second layer of ferromagnetic material.

2. The magnetoresistive memory element of claim 1 , wherein the first high-iron interface region includes a discontinuous atomic layer of iron.

3. The magnetoresistive memory element of claim 1 , wherein the first high-iron interface region includes iron and boron.

4. The magnetoresistive memory element of claim 1 , wherein the free magnetic layer includes perpendicular magnetic anisotropy.

5. The magnetoresistive memory element of claim 1 , wherein the free magnetic layer further includes:
a second high-iron interface region located along the second surface of the free magnetic layer, wherein the second high-iron interface region has at least 50% iron by atomic composition.

6. The magnetoresistive memory element of claim 5 , wherein the second high-iron interface region includes a discontinuous atomic layer of iron.

7. The magnetoresistive memory element of claim 5 , further including:
a second insertion layer located between the second layer of ferromagnetic material and the second high-iron interface region, wherein the second insertion layer (i) includes a non-ferromagnetic transition metal and (ii) does not break direct exchange coupling between the second layer of ferromagnetic material and the second high-iron interface region.

8. The magnetoresistive memory element of claim 1 , wherein the first non-ferromagnetic transition metal is tantalum, titanium, molybdenum, niobium, vanadium, zirconium, hafnium, chromium, manganese, or tungsten.

9. The magnetoresistive memory element of claim 8 , wherein the first insertion layer is a discontinuous layer.

10. A magnetoresistive memory element, comprising:
a first fixed magnetic layer;
a first dielectric layer having a first surface and a second surface, the first dielectric layer disposed over the first fixed magnetic layer along the first surface of the first dielectric layer;
a second dielectric layer disposed over the first dielectric layer and having a first surface and a second surface;
a fixed, unpinned synthetic antiferromagnet (SAF) disposed over the second dielectric layer, wherein the fixed, unpinned SAF includes a second fixed magnetic layer disposed over and along the first surface of the second dielectric layer; and
a free magnetic layer, disposed between the first and second dielectric layers, having a first surface in contact with the second surface of the first dielectric layer and a second surface in contact with the second surface of the second dielectric layer, wherein the free magnetic layer includes:
a high-iron interface region located along the second surface of the free magnetic layer, wherein the high-iron interface region has at least 50% iron by atomic composition,
a first layer of ferromagnetic material adjacent to the high-iron interface region, the high-iron interface region disposed between the first layer of ferromagnetic material and the second surface of the free magnetic layer,
a second layer of ferromagnetic material disposed between the first layer of ferromagnetic material and the first surface of the free magnetic layer, and
a first insertion layer located between the first layer of ferromagnetic material and the second layer of ferromagnetic material, wherein the first insertion layer includes a non-ferromagnetic transition metal.

11. The magnetoresistive memory element of claim 10 , wherein the high-iron interface region includes a discontinuous atomic layer of iron.

12. The magnetoresistive memory element of claim 10 , wherein high-iron interface region includes iron and boron.

13. The magnetoresistive memory element of claim 10 , wherein the non-ferromagnetic transition metal is tantalum, titanium, molybdenum, niobium, vanadium, zirconium, hafnium, chromium, manganese, or tungsten.

14. The magnetoresistive memory element of claim 10 , wherein the first insertion layer is a discontinuous layer.

15. A magnetoresistive memory element, comprising:
a first fixed magnetic layer;
a first dielectric layer having a first surface and a second surface, the first dielectric layer juxtaposed the first fixed magnetic layer along the first surface of the first dielectric layer;
a second dielectric layer having a first surface and a second surface;
a fixed, unpinned synthetic antiferromagnet (SAF) juxtaposed the second dielectric layer, wherein the fixed, unpinned SAF includes a second fixed magnetic layer disposed along the first surface of the second dielectric layer; and
a free magnetic layer, disposed between the first and second dielectric layers, having a first surface in contact with the second surface of the first dielectric layer and a second surface in contact with the second surface of the second dielectric layer, wherein the free magnetic layer includes:
a first high-iron interface region located along the first surface of the free magnetic layer, wherein the high-iron interface region has at least 50% iron by atomic composition,
a second high-iron interface region located along the second surface of the free magnetic layer, wherein the high-iron interface region has at least 50% iron by atomic composition, and
a first layer of ferromagnetic material disposed between the first high-iron interface region and the second high-iron interface region, wherein the first layer of ferromagnetic material includes cobalt and iron.

16. The magnetoresistive memory element of claim 15 , wherein:
the first high-iron interface region includes a discontinuous atomic layer of iron, and
the second high-iron interface region includes a discontinuous atomic layer of iron.

17. The magnetoresistive memory element of claim 15 , wherein (i) the first high-iron interface region includes iron and boron and (ii) the second high-iron interface region includes iron and boron.

18. The magnetoresistive memory element of claim 15 , wherein the free magnetic layer furthe

Assignees

• Everspin Technologies Inc

Inventors

• Whig Renu
• Sun Jijun
• Rizzo Nicholas
• Slaughter Jon
• Houssameddine Dimitri
• Mancoff Frederick

Classifications

• G11C11/161 Primary

  details concerning the memory cell structure, e.g. the layers of the ferromagnetic memory cell · CPC title

• H01L43/02

  Electricity · mapped topic

• H01L43/08

  Electricity · mapped topic

• H01L43/10

  Electricity · mapped topic

• H01L43/12 Primary

  Electricity · mapped topic