HIGH STABILITY SPINTRONIC MEMORY

• US 20140291663A1
• Filed: 03/28/2013
• Published: 10/02/2014
• Est. Priority Date: 03/28/2013
• Status: Active Grant

• Current Assignee: Tahoe Research Limited (f/k/a Learndale Limited) (Vector Capital Corporation)
• Original Assignee: Intel Corporation
• Inventors: Kuo, Charles, Oguz, Kaan, Doyle, Brian, Mojarad, Roksana Golizadeh, Kencke, David, Chau, Robert, Karpov, Elijah Ilya
• Granted Patent: US 9,231,194 B2
• Time in Patent Office: Days
• US Class Current: 257/43
• CPC Class Codes: G11C 11/161 details concerning the memory cell structure, e.g. the layers of the ferromagnetic memory cell
• CPC Class Codes: H01F 10/3286 Spin-exchange coupled multilayers having at least one layer with perpendicular magnetic anisotropy
• CPC Class Codes: H01F 10/329 Spin-exchange coupled multilayers wherein the magnetisation of the free layer is switched by a spin-polarised current, e.g. spin torque effect
• 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
• CPC Class Codes: H10N 52/01 Manufacture or treatment
• CPC Class Codes: H10N 52/101 Semiconductor Hall-effect devices

Abstract

An embodiment includes a magnetic tunnel junction (MTJ) including a free magnetic layer, a fixed magnetic layer, and a tunnel barrier between the free and fixed layers; the tunnel barrier directly contacting a first side of the free layer; and an oxide layer directly contacting a second side of the free layer; wherein the tunnel barrier includes an oxide and has a first resistance-area (RA) product and the oxide layer has a second RA product that is lower than the first RA product. The MTJ may be included in a perpendicular spin torque transfer memory. The tunnel barrier and oxide layer form a memory having high stability with an RA product not substantively higher than a less table memory having a MTJ with only a single oxide layer. Other embodiments are described herein.

Claims

1. An apparatus comprising:

a magnetic tunnel junction (MTJ) including a free magnetic layer, a fixed magnetic layer, and a tunnel barrier between the free and fixed layers;

the tunnel barrier directly contacting a first side of the free layer; and

an oxide layer directly contacting a second side of the free layer;

wherein the tunnel barrier includes an oxide and has a first resistance-area (RA) product and the oxide layer has a second RA product that is lower than the first RA product.

2. The apparatus of claim 1, wherein the tunnel barrier includes magnesium oxide and the oxide layer includes at least one of tungsten oxide, vanadium oxide, indium oxide, aluminum oxide, ruthenium oxide, and tantalum oxide.

3. The apparatus of claim 2, wherein the second RA product is less than 10 mOhm-cm².

4. The apparatus of claim 3, wherein the second side is primarily located in a plane and the free layer has a thickness, orthogonal to the plane, of less than 2 nm.

5. The apparatus of claim 4, wherein the tunnel barrier has a thickness less than 3 nm and greater than the thickness of the free layer.

6. The apparatus of claim 2, wherein the free layer includes cobalt, iron, and boron.

7. The apparatus of claim 1 comprising a perpendicular spin torque transfer memory (STTM) that includes the MTJ.

8. The apparatus of claim 1, wherein the second side is in a plane and the free layer has a thickness, orthogonal to the plane, less than a thickness of the tunnel barrier layer.

9. The apparatus of claim 1, wherein the tunnel barrier includes a first metal and the oxide layer includes a second metal unequal to the first metal.

10. The apparatus of claim 1, wherein the first side is directly opposite the second side.

11. The apparatus of claim 10 comprising alternating layers of first and second materials, wherein one of the alternating layers directly contacts the oxide layer opposite where the free layer contacts the oxide layer.

12. The apparatus of claim 1, wherein the oxide layer, the fixed and free layers, and the tunnel barrier are all thin films.

13. The apparatus of claim 1, wherein the second RA product is less than 10% of the first RA product.

14. The apparatus of claim 1, wherein the MTJ has perpendicular anisotropy.

15. A method comprising:

forming a magnetic tunnel junction (MTJ) on a substrate, the MTJ including a free magnetic layer, a fixed magnetic layer, and a tunnel barrier layer between the free and fixed layers;

the tunnel barrier directly contacting a first side of the free layer; and

forming an oxide layer directly contacting a second side of the free layer;

wherein the tunnel barrier has a first resistance-area (RA) product and the oxide layer has a second RA product that is lower than the first RA product.

16. The method of claim 15, wherein the oxide layer, the fixed and free layers, and the tunnel barrier are all thin films.

17. The method of claim 16, wherein the second side is primarily located in a plane and the free layer has a thickness, orthogonal to the plane, of less than 2 nm and the tunnel barrier layer has a thickness less than 3 nm and greater than the thickness of the free layer.

18. The method of claim 16, wherein the second RA product is less than 10% of the first RA product.

19. A perpendicular spin torque transfer memory (STTM) comprising:

a magnetic tunnel junction (MTJ) including a tunnel barrier layer between free and fixed layers and directly contacting a side of the free layer; and

an oxide layer directly contacting an opposing side of the free layer;

wherein the tunnel barrier has a first resistance-area (RA) product and the oxide layer has a second RA product that is lower than the first RA product.

20. The memory of claim 19, wherein the second RA product is less than 10% of the first RA product.

21. The memory of claim 20, wherein the oxide layer, the fixed and free layers, and the tunnel barrier are all thin films.