Magnetic tunnel junction transistor device

• US 8,233,249 B2
• Filed: 01/04/2010
• Issued: 07/31/2012
• Est. Priority Date: 01/04/2010
• Status: Active Grant

• Current Assignee: Globalfoundries US Incorporated (GlobalFoundries, Inc.)
• Original Assignee: International Business Machines Corporation
• Inventors: Worledge, Daniel C.
• Primary Examiner(s): Klimowicz, Will J
• Application Number:
  US12/651,804
• Publication Number:
  US 20110164338A1
• Time in Patent Office: 939 Days
• Field of Search: 360/324.2, 360/314, 257/295, 257/421, 257/E27.006, 257/E27.104
• US Class Current: 360/324.2
• CPC Class Codes: B82Y 25/00 Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• CPC Class Codes: G01R 33/098 comprising tunnel junctions, e.g. tunnel magnetoresistance sensors
• 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

Abstract

A magnetic tunnel junction transistor (MTJT) device includes a source-drain region comprising a source electrode and a drain electrode, a double MTJ element formed between the source electrode and the drain electrode and comprising a free magnetic layer at a center region thereof, and a gate region adjacent to the source-drain region and comprising an insulating barrier layer formed on an upper layer of the double MTJ element and a gate electrode formed on the insulating barrier layer. The MTJT device switches a magnetization orientation of the free magnetic layer by application of a gate voltage to the gate electrode, thereby changing a resistance of the source-drain region.

Claims

1. A magnetic tunnel junction transistor (MTJT) device comprising:

a source-drain region comprising a source electrode and a drain electrode;

a double MTJ element formed between the source electrode and the drain electrode and comprising a free magnetic layer at a center region thereof; and

a gate region adjacent to the source-drain region and comprising an insulating barrier layer formed on an upper layer of the double MTJ element and a gate electrode formed on the barrier layer,

the magnetic tunnel junction device switching a magnetization orientation of the free magnetic layer by application of a gate voltage to the gate electrode, thereby changing a resistance of the source-drain region.

2. The MTJT device of claim 1, wherein the double MTJ element further comprises:

a first pinned layer formed on the drain electrode;

a first tunnel barrier layer formed on the first pinned layer;

the free magnetic layer formed on the first tunnel barrier layer;

a second tunnel barrier layer formed on the free magnetic layer; and

a second pinned layer formed on the second tunnel barrier layer and contacting the source electrode.

3. The MTJT device of claim 2, wherein the MTJT device switches between an on state and an off state based on the gate voltage applied to the gate electrode.

4. The MTJT device of claim 3, wherein the gate voltage ranges between approximately 0 millivolts (mV) to approximately 100 (mV).

5. The MTJT device of claim 3, wherein when the MTJT device is in an off state, the magnetization orientation of the free magnetic layer is in plane with a magnetization orientation of the first and second pinned layers such that a resistance of the source-drain region is in a high resistance state.

6. The MTJT device of claim 5, wherein when the gate voltage is applied to the gate electrode, the MTJT device is switched to an on state, and the magnetization orientation of the free magnetic layer is perpendicular to the magnetization orientation of the first and second pinned layers such that the resistance of the source-drain region is in a low resistance state.

7. The MTJT device of claim 6, wherein the source electrode, the drain electrode and the gate electrode are formed of tantalum.

8. The MTJT device of claim 6, wherein the first and second pinned layers are formed of a magnetic material including at least one of cobalt (Co), or iron (Fe), or any combination thereof.

9. The MTJT device of claim 8, wherein the first and second pinned layers are of a predetermined thickness ranging from approximately 1 nanometers (nm) to approximately 5 nanometers (nm).

10. The MTJT device of claim 6, wherein the free magnetic layer is formed of at least one of cobalt (Co), or iron (Fe), or any combination thereof.

11. The MTJT device of claim 10, wherein the free magnetic layer is of a predetermined thickness ranging from approximately 0.3 nanometers (nm) to approximately 1 nanometer (nm).

12. The MTJT device of claim 6, wherein the insulating barrier layer is formed of a predetermined thickness ranging from approximately 0.5 nanometer (nm) to approximately 2 nanometers (nm).

13. The MTJT device of claim 12, wherein the insulating barrier layer is formed on the second tunnel barrier layer.

14. The MTJT device of claim 13, wherein the insulating barrier layer and the first and second tunnel barrier layers are formed of at least one of magnesium oxide (MgO), aluminum oxide (AlO), or titanium oxide (TiO).

15. The MTJT device of claim 14, wherein the first and second tunnel barrier layers are each formed of a predetermined thickness ranging from approximately 0.5 nanometers (nm) to approximately 2 nanometers (nm).

16. A magnetic tunnel junction transistor (MTJT) device comprising:

three electrical terminals including a source electrode, and a drain electrode and gate electrode;

a double MTJ element formed between the source electrode and the drain electrode and comprising a free magnetic layer at a center region thereof; and

an insulating barrier layer formed on an upper layer of the double MTJ element contacting the gate electrode,

the magnetic tunnel junction device switching a magnetization orientation of the free magnetic layer by applying a gate voltage to the gate electrode, thereby changing a resistance between the source electrode and the drain electrode.

17. A method for forming a magnetic tunnel junction transistor (MTJT) device, the method comprising:

forming a source-drain region comprising a source electrode and a drain electrode;

forming a double MTJ element between the source electrode and the drain electrode and comprising a free magnetic layer at a center region thereof; and

forming a gate region adjacent to the source-drain region and comprising an insulating barrier layer formed on an upper layer of the double MTJ element and a gate electrode formed on the insulating barrier layer;

wherein a magnetization orientation of the free magnetic layer is switched by application of a gate voltage to the gate electrode, thereby changing a resistance of the source-drain region.

18. The method of claim 17, wherein forming the double MTJ element comprises:

forming a first pinned layer on the drain electrode;

forming a first tunnel barrier layer on the first pinned layer;

forming the free magnetic layer on the first tunnel barrier layer;

forming a second tunnel barrier layer on the free magnetic layer; and

forming a second pinned layer on the second tunnel barrier layer and contacting the source electrode.

19. A method for operating a magnetic tunnel junction transistor (MTJT) device having a source electrode, and a drain electrode and gate electrode, a double MTJ element formed between the source electrode and the drain electrode and comprising a free magnetic layer at a center region thereof, and an insulating barrier layer formed on an upper layer of the double MTJ element contacting the gate electrode, the method comprising:

switching a magnetization orientation of the free magnetic layer by application of a gate voltage to the gate electrode, thereby changing a resistance between the source electrode and the drain electrode.

20. The method of claim 19, wherein the MTJT device switches between an on state and an off state based on the gate voltage applied to the gate electrode.

21. The method of claim 20, wherein the gate voltage ranges between approximately 0 millivolts (mV) to approximately 100 (mV).

22. The method of claim 20, wherein when the MTJT device is in an off state, the magnetization orientation of the free magnetic layer is in plane with a magnetization orientation of the first and second pinned layers such that a resistance of the source-drain region is in a high resistance state.

23. The method of claim 22, wherein when the gate voltage is applied to the gate electrode, the MTJT device is switched to an on state, and the magnetization orientation of the free magnetic layer is perpendicular to the magnetization orientation of the first and second pinned layers such that the resistance of the source-drain region is in a low resistance state.