# US 2018/0322994 A1 · Thermal budget enhancement of a magnetic tunnel junction

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2018/0322994 A1
- Document ID: US20180322994A1
- Status: Published application
- Kind: A1
- Application number: 15/773,339
- Filed: 2015-12-07
- Published: 2018-11-08
- Earliest claimed: 2015-12-07
- Assignees: Intel Corporation
- Applicants: Intel Corporation
- Inventors: Tofizur RAHMAN; Christopher J. WIEGAND; Daniel B. BERGSTROM
- Web page: https://patentgrep.com/patent/US20180322994A1

## CPC

- H01F 10/3254: {the spacer being semiconducting or insulating, e.g. for spin tunnel junction [STJ]}
- G11C 11/161: {details concerning the memory cell structure, e.g. the layers of the ferromagnetic memory cell}
- H01F 10/3272: {by use of anti-parallel coupled [APC] ferromagnetic layers, e.g. artificial ferrimagnets [AFI], artificial [AAF] or synthetic [SAF] anti-ferromagnets}
- H01F 41/32: for applying conductive, insulating or magnetic material on a magnetic film {, specially adapted for a thin magnetic film}
- H10B 61/00: Magnetic memory devices, e.g. magnetoresistive RAM [MRAM] devices
- H10N 50/01: Manufacture or treatment
- H10N 50/10: Magnetoresistive devices
- H10N 50/80: Constructional details
- H10N 50/85: Materials of the active region
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- G11C: STATIC STORES (semiconductor memory devices H10B)
- H10B: ELECTRONIC MEMORY DEVICES
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR

## Abstract

Embodiments of the disclosure are directed to a magnetic tunneling junction (MTJ) that includes a diffusion barrier. The diffusion barrier can be disposed between two ferromagnetic layers of the MTJ. More specifically, the diffusion barrier can be disposed between a first ferromagnetic layer, which is adjacent to a natural antiferromagnetic layer, and a second ferromagnetic layer; the first and second ferromagnetic layers and the diffusion barrier being part of a synthetic antiferromagnet. The diffusion barrier can be made of a refractory metal, such as tantalum. The diffusion barrier acts as a barrier for manganese diffusion from the natural antiferromagnetic layer into the synthetic antiferromagnet and other higher layers of the MTJ.

## Claims

### Claim 1

A magnetic tunneling junction (MTJ) stack comprising:
an antiferromagnetic layer comprising manganese (Mn);
a ferromagnetic layer; and
a diffusion barrier, the diffusion barrier comprising a material that is a barrier to Mn diffusion, the ferromagnetic layer residing between the antiferromagnetic layer and the diffusion barrier.

### Claim 2 (depends on 1)

The MTJ stack of claim 1, wherein the diffusion barrier comprises a refractory metal.

### Claim 3 (depends on 1)

The MTJ stack of claim 1, wherein the diffusion barrier comprises one of tantalum, molybdenum, tungsten, niobium, hafnium, zirconium, or titanium.

### Claim 4 (depends on 1)

The MTJ stack of claim 1, wherein the ferromagnetic layer comprises an alloy of cobalt and iron.

### Claim 5 (depends on 1)

The MTJ stack of claim 1, wherein the ferromagnetic layer is a first ferromagnetic layer, the MTJ stack further comprising a second ferromagnetic layer comprising an alloy of cobalt and iron, the diffusion barrier disposed between the first ferromagnetic layer and the second ferromagnetic layer.

### Claim 6 (depends on 5)

The MTJ stack of claim 5, wherein the first and second ferromagnetic layers are strongly ferromagnetically coupled to the antiferromagnetic layer.

### Claim 7 (depends on 6)

The MTJ stack of claim 6, wherein the first and second ferromagnetic layers comprise a magnetic exchange bias at or above 550 Oersted.

### Claim 8 (depends on 1)

The MTJ stack of claim 1, wherein the diffusion barrier comprises a thickness of 1-10 Å.

### Claim 9 (depends on 1)

The MTJ stack of claim 1, wherein the antiferromagnetic layer comprises platinum manganese.

### Claim 10

A method of creating a magnetic tunneling junction (MTJ) stack, the method comprising:
forming an antiferromagnetic layer;
forming a first ferromagnetic layer;
forming a diffusion barrier on the first ferromagnetic layer; and
forming a second ferromagnetic layer.

### Claim 11 (depends on 10)

The method of claim 10, wherein forming the antiferromagnetic layer comprises:
depositing a seed layer;
depositing the antiferromagnetic layer;
heating the antiferromagnetic layer to a predetermined temperature;
applying a magnetic field to the antiferromagnetic layer; and
cooling the antiferromagnetic layer in the presence of the magnetic field.

### Claim 12 (depends on 10)

The method of claim 10, wherein the antiferromagnetic layer comprises platinum manganese.

### Claim 13 (depends on 10)

The method of claim 10, wherein the diffusion barrier comprises a refractory metal.

### Claim 14 (depends on 10)

The method of claim 10, wherein the diffusion barrier comprises one of tantalum, molybdenum, tungsten, niobium, hafnium, zirconium, or titanium.

### Claim 15 (depends on 10)

The method of claim 10, wherein forming the diffusion barrier comprises sputtering a diffusion barrier material to a thickness in a range between 1-10 Å.

### Claim 16 (depends on 10)

The method of claim 10, further comprising annealing the MTJ stack to a temperature above 400 C.

### Claim 17 (depends on 10)

The method of claim 10, wherein the first and second ferromagnetic layers comprise an alloy of cobalt and iron.

### Claim 18 (depends on 10)

The method of claim 10, further comprising forming a synthetic antiferromagnet, the synthetic antiferromagnet comprising the first ferromagnetic layer, the diffusion barrier, and the second ferromagnetic layer, a ruthenium layer and a reference layer.

### Claim 19

A computing device comprising:
a processor mounted on a substrate;
a communications logic unit within the processor;
a memory within the processor;
a graphics processing unit within the computing device;
an antenna within the computing device;
a display on the computing device;
a battery within the computing device;
a power amplifier within the processor;
a voltage regulator within the processor; and
a non-volatile memory;
wherein the non-volatile memory comprises:
a magnetic tunneling junction (MTJ) stack comprising:
an antiferromagnetic layer comprising platinum manganese (PtMN);
a ferromagnetic layer; and
a diffusion barrier, the diffusion barrier comprising a material that is a barrier to Mn diffusion, the ferromagnetic layer residing between the antiferromagnetic layer and the diffusion barrier;
wherein the diffusion barrier comprises a refractory metal.

### Claim 20 (depends on 19)

The computing device of claim 19, wherein the diffusion barrier comprises one of tantalum, molybdenum, tungsten, niobium, hafnium, zirconium, or titanium.

### Claim 21 (depends on 19)

The computing device of claim 19, wherein the ferromagnetic layer comprises an alloy of cobalt and iron.

### Claim 22 (depends on 19)

The computing device of claim 19, wherein the ferromagnetic layer is a first ferromagnetic layer, the MTJ stack further comprising a second ferromagnetic layer comprising an alloy of cobalt and iron, the diffusion barrier disposed between the first ferromagnetic layer and the second ferromagnetic layer.

### Claim 23 (depends on 22)

The computing device of claim 22, wherein the first and second ferromagnetic layers are strongly ferromagnetically coupled to the antiferromagnetic layer.

### Claim 24 (depends on 23)

The computing device of claim 23, wherein the first and second ferromagnetic layers comprise a magnetic exchange bias at or above 550 Oersted.

### Claim 25 (depends on 19)

The computing device of claim 19, wherein the diffusion barrier comprises a thickness of 1-10 Å.