MAGNETIC TUNNEL JUNCTION FOR MRAM DEVICE

• US 20150279904A1
• Filed: 04/01/2014
• Published: 10/01/2015
• Est. Priority Date: 04/01/2014
• Status: Abandoned Application

• Current Assignee: Spin Transfer Technologies, Inc.
• Original Assignee: Spin Transfer Technologies, Inc.
• Inventors: Pinarbasi, Mustafa, Kardasz, Bartek
• Application Number:
  US14/242,419
• Publication Number:
  US 20150279904A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G11C 11/161 details concerning the memory cell structure, e.g. the layers of the ferromagnetic memory cell
• CPC Class Codes: H01L 29/66984 Devices using spin polarized carriers
• CPC Class Codes: H01L 29/82 controllable by variation of the magnetic field applied to the device
• 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 random-access memory device with a magnetic tunnel junction stack having a significantly improved performance of the free layer in the magnetic tunnel junction structure. The memory device includes an antiferromagnetic structure and a magnetic tunnel junction structure disposed on the antiferromagnetic structure. The magnetic tunnel junction structure includes a reference layer and a free layer with a barrier layer sandwiched therebetween. Furthermore, a capping layer including a tantalum nitride film is disposed on the free layer of the magnetic tunnel junction structure.

Claims

1. A magnetic device, comprising:

an antiferromagnetic structure including a reference layer;

a barrier layer disposed on the reference layer;

a free layer disposed on the barrier layer;

a thin tantalum nitride capping layer disposed on the free layer, wherein the thin tantalum nitride capping layer comprises a thickness between 0.1 and 10 nanometers, and which keeps the damping constant of the free layer to 0.011 or lower;

a nonmagnetic spacer disposed on the thin tantalum nitride capping layer, the nonmagnetic spacer comprised of a copper laminate;

a perpendicular polarizer layer disposed on the nonmagnetic spacer, the perpendicular polarizer layer magnetized perpendicularly to free layer, thereby forming an orthogonal spin transfer torque structure; and

wherein the reference layer, the free layer, the barrier layer and the thin tantalum nitride capping layer collectively form a magnetic tunnel junction.

3. The magnetic device according to claim 1, wherein the thin tantalum nitride capping layer comprises a thickness of approximately 1.0 nanometer.

4. The magnetic device according to claim 1, wherein the thin tantalum nitride capping layer comprises a thickness of approximately 10 nanometers.

5. The magnetic device according to claim 1, wherein the thin tantalum nitride capping layer is disposed directly on the free layer.

6. The magnetic device according to claim 1

wherein the perpendicular polarizer disposed on the nonmagnetic spacer, such that the perpendicular polarizer polarizes a current of electrons applied to the magnetic device.

7. The magnetic device according to claim 6, wherein the magnetic device is an orthogonal spin transfer torque structure.

9. The magnetic device according to claim 1, wherein the thin tantalum nitride capping layer is formed on the free layer by a thin film sputter process with a tantalum target and a nitrogen gas.

11. The magnetic device according to claim 1, wherein the reference layer and the free layer each comprise a CoFeB thin film layer having a thickness of approximately 2.3 nm.

12. The magnetic device according to claim 11, wherein the barrier layer comprise MgO and has a thickness of approximately 1.02 nm.

21. The magnetic device according to claim 1, wherein the nonmagnetic spacer is approximately 10 nm thick.

2. (canceled)

8. (canceled)

10. (canceled)

13. A memory array comprising:

at least one bit cell including;

an antiferromagnetic structure including a reference layer;

a barrier layer disposed on the reference layer;

a free layer disposed on the barrier layer;

a thin tantalum nitride capping layer disposed on the free layer, wherein the thin tantalum nitride capping layer comprises a thickness between 0.1 and 10 nanometers, and which keeps the damping constant of the free layer to 0.011 or lower;

a nonmagnetic spacer disposed on the thin tantalum nitride capping layer, the nonmagnetic spacer comprised of a copper laminate;

a perpendicular polarizer layer disposed on the nonmagnetic spacer, the perpendicular polarizer layer magnetized perpendicularly to free layer, thereby forming an orthogonal spin transfer torque structure; and

wherein the reference layer, the free layer, the barrier layer and the thin tantalum nitride capping layer collectively form a magnetic tunnel junction.

15. The memory array according to claim 13, wherein the thin tantalum nitride capping layer of the at least one bit cell comprises a thickness of approximately 1.0 nanometer.

16. The memory array according to claim 13, wherein the thin tantalum nitride capping layer of the at least one bit cell comprises a thickness of approximately 10 nanometers.

17. The memory array according to claim 13, wherein the thin tantalum nitride capping layer of the at least one bit cell is disposed directly on the free layer.

18. The memory array according to claim 13, wherein

the perpendicular polarizer polarizes a current of electrons applied to the magnetic device.

19. The memory array according to claim 18, wherein the at least one bit cell is an orthogonal spin transfer torque structure.

22. The memory array according to claim 13, wherein the nonmagnetic spacer is approximately 10 nm thick.

14. (canceled)

20. (canceled)