Spin-torque based memory device using a magnesium oxide tunnel barrier

• US 8,406,040 B2
• Filed: 01/08/2010
• Issued: 03/26/2013
• Est. Priority Date: 01/08/2010
• Status: Expired due to Fees

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Worledge, Daniel C., Hu, Guohan, Sun, Jonathan Z.
• Primary Examiner(s): BERNATZ, KEVIN M
• Application Number:
  US12/684,530
• Publication Number:
  US 20110171493A1
• Time in Patent Office: 1,173 Days
• Field of Search: None
• US Class Current: 365/158
• CPC Class Codes: B82Y 25/00 Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• 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: H01F 10/3254 the spacer being semiconducting or insulating, e.g. for spin tunnel junction [STJ]
• CPC Class Codes: H01F 10/3286 Spin-exchange coupled multilayers having at least one layer with perpendicular magnetic anisotropy
• CPC Class Codes: H10N 50/10 Magnetoresistive devices
• CPC Class Codes: Y10T 428/1114 having tunnel junction effect
• CPC Class Codes: Y10T 428/1121 Multilayer
• CPC Class Codes: Y10T 428/1143 with defined structural feature

Abstract

A magnetic tunnel junction stack including a pinned magnetic layer, a tunnel barrier layer formed of magnesium oxide (MgO), a free magnetic layer adjacent to the tunnel barrier layer, and a layer of vanadium (V) adjacent to the free magnetic layer.

Claims

1. A magnetic tunnel junction stack comprising:

a pinned magnetic layer;

a tunnel barrier layer formed of magnesium oxide (MgO);

a free magnetic layer adjacent to the tunnel barrier layer; and

a layer consisting of vanadium (V) directly adjacent to the free magnetic layer;

wherein the layer of vanadium (V) is of a predetermined thickness of greater than 10 Angstroms and disposed on one of the top or bottom surface of the magnetic tunnel junction stack.

2. The magnetic tunnel junction stack of claim 1, wherein the free magnetic layer includes at least one of iron (Fe) or cobalt (Co).

3. The magnetic tunnel junction stack of claim 1, wherein the free magnetic layer includes a layer of CoFeB.

4. A magnetic tunnel junction stack comprising:

a pinned magnetic layer;

a tunnel barrier layer formed of magnesium oxide (MgO);

a free magnetic layer adjacent to the tunnel barrier layer, wherein the free magnetic layer includes a plurality of elements wherein at least one element is vanadium; and

a layer consisting of vanadium (V) directly adjacent to the free magnetic layer;

wherein the layer of vanadium (V) is of a predetermined thickness of greater than 10 Angstroms and disposed on one of the top or bottom surface of the magnetic tunnel junction stack.

5. The magnetic tunnel junction stack of claim 4, wherein the free magnetic layer is formed of a multilayer of iron (Fe), vanadium (V) and cobalt (Co).

6. The magnetic tunnel junction stack of claim 5, wherein the free magnetic layer is formed of multilayer of [x Fe|y V|z Fe] * n, wherein x and z are predetermined thicknesses ranging from approximately 5 to 15 angstroms and y is a predetermined thickness ranging from approximately 1 to 10 angstroms and n represents a predetermined number of layers.

7. The magnetic tunnel junction stack of claim 5, wherein the free magnetic layer is formed of multilayer of [x FeCo|y V|z FeCo] * n, wherein x and z are predetermined thicknesses ranging from approximately 5 to 15 angstroms and y is a predetermined thickness ranging from approximately 1 to 10 angstroms and n represents a predetermined number of layers.

8. The magnetic tunnel junction stack of claim 4, wherein the free magnetic layer is formed of multilayers of iron (Fe), vanadium (V), cobalt (Co) and boron (B) or a combination of alloys thereof.

9. The magnetic tunnel junction stack of claim 8 wherein the free magnetic layer is formed of multilayer of [x FeCoB|y V|z FeCoB] * n, wherein x and z are predetermined thicknesses ranging from approximately 5 to 15 angstroms and y is a predetermined thickness ranging from approximately 1 to 10 angstroms and n represents a predetermined number of layers.

10. The magnetic tunnel junction stack of claim 4, wherein the free magnetic layer is formed on a seed layer comprising one of silver (Ag) or vanadium (V).

11. A magnetic random access memory device comprising:

a magnetic tunnel junction stack including;

a pinned magnetic layer;

a tunnel barrier layer formed of magnesium oxide (MgO);

a free magnetic layer adjacent to the tunnel barrier layer; and

a layer consisting of vanadium (V) directly adjacent to the free magnetic layer;

wherein the layer of vanadium (V) is of a predetermined thickness of greater than 10 Angstroms and disposed on one of the top or bottom surface of the magnetic tunnel junction stack.

12. The magnetic random access memory device of claim 11, wherein the free magnetic layer includes at least one of iron (Fe) or cobalt (Co).

13. The magnetic random access memory device of claim 11, wherein the free magnetic layer includes a layer of CoFeB.

14. A magnetic random access memory device comprising:

a magnetic tunnel junction stack including;

a pinned magnetic layer;

a tunnel barrier layer formed of magnesium oxide (MgO);

a free magnetic layer adjacent to the tunnel barrier layer, wherein the free magnetic layer includes a plurality of elements wherein at least one element is vanadium; and

a layer consisting of vanadium (V) directly adjacent to the free magnetic layer;

wherein the layer of vanadium (V) is of a predetermined thickness of greater than 10 Angstroms and disposed on one of the top or bottom surface of the magnetic tunnel junction stack.

15. The magnetic random access memory device of claim 14, wherein the free magnetic layer is formed on a seed layer comprising one of silver (Ag) or vanadium (V).

16. The magnetic random access memory device of claim 14, wherein an interface region between the free magnet layer and the tunnel barrier layer comprises an alloy formed of vanadium (V).

17. The magnetic random access memory device of claim 14, wherein the free magnetic layer is formed of a multilayer of iron (Fe), vanadium (V) and cobalt (Co).

18. The magnetic random access memory device of claim 17, wherein the free magnetic layer is formed of multilayer of x Fe|y V|z Fe] * n, wherein x and z are predetermined thicknesses ranging from approximately 5 to 15 angstroms and y is a predetermined thickness ranging from approximately 1 to 10 angstroms and n represents a predetermined number of layers.

19. The magnetic random access memory device of claim 17, wherein the free magnetic layer is formed of multilayer of [x FeCo|y V|z FeCo] * n, wherein x and z are predetermined thicknesses ranging from approximately 5 to 15 angstroms and y is a predetermined thickness ranging from approximately 1 to 10 angstroms and n represents a predetermined number of layers.

20. The magnetic random access memory device of claim 14, wherein the free magnetic layer is formed of multilayers of iron (Fe), vanadium (V), cobalt (Co) and boron (B) or a combination of alloys thereof.

21. The magnetic random access memory device of claim 20 wherein the free magnetic layer is formed of multilayer of [x FeCoB|y V|z FeCoB] * n, wherein x and z are predetermined thicknesses ranging from approximately 5 to 15 angstroms and y is a predetermined thickness ranging from approximately 1 to 10 angstroms and n represents a predetermined number of layers.