# US 2025/0098547 A1 · Magnetoresistive effect element and magnetic memory

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- Number: US 2025/0098547 A1
- Document ID: US20250098547A1
- Status: Published application
- Kind: A1
- Application number: 18/470,708
- Filed: 2023-09-20
- Published: 2025-03-20
- Earliest claimed: 2023-09-20
- Assignees: TDK Corporation
- Applicants: TDK Corporation
- Inventors: Shuji OKAME; Tomoyuki SASAKI; Zhenyao TANG
- Web page: https://patentgrep.com/patent/US20250098547A1

## CPC

- H10N 50/20: Spin-polarised current-controlled devices (magnetoresistive devices H10N50/10)
- H10B 61/00: Magnetic memory devices, e.g. magnetoresistive RAM [MRAM] devices
- H10B 61/22: {of the field-effect transistor [FET] type}
- H10N 50/01: Manufacture or treatment
- H10N 50/10: Magnetoresistive devices
- H10N 50/85: Materials of the active region
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10B: ELECTRONIC MEMORY DEVICES

## Abstract

The magnetic memory of the present disclosure comprises a plurality of magnetoresistive effect elements. Each of the magnetoresistive effect elements comprises a reference layer, a magnetization free layer, a tunnel barrier layer provided between the reference layer and the magnetization free layer, a first cap layer provided on the magnetization free layer, a second cap layer; and a ferromagnetic layer provided between the first cap layer and the second cap layer. The ferromagnetic layer has a thickness less than a thickness of the magnetization free layer.

## Claims

### Claim 1

A magnetoresistive effect element comprising:
a reference layer;
a magnetization free layer;
a tunnel barrier layer provided between the reference layer and the magnetization free layer;
a first cap layer provided on the magnetization free layer;
a second cap layer; and
a ferromagnetic layer provided between the first cap layer and the second cap layer, the ferromagnetic layer having a thickness that is less than a thickness of the magnetization free layer.

### Claim 2 (depends on 1)

The magnetoresistive effect element according to claim 1, wherein the thickness of the ferromagnetic layer is 0.5 nm or less.

### Claim 3 (depends on 1)

The magnetoresistive effect element according to claim 1, wherein the thickness of the ferromagnetic layer is less than a thickness sufficient to cause self-magnetization in the ferromagnetic layer.

### Claim 4 (depends on 1)

The magnetoresistive effect element according to claim 1, wherein the ferromagnetic layer includes Fe and Co, and a concentration of Co decreases as the ferromagnetic layer approaches the second cap layer.

### Claim 5 (depends on 1)

The magnetoresistive effect element according to claim 1, wherein the ferromagnetic layer comprises a plurality of islands distributed two-dimensionally on the first cap layer.

### Claim 6 (depends on 1)

The magnetoresistive effect element according to claim 1, wherein the first cap layer comprises an oxide layer, a thickness of the oxide layer being less than a thickness of the tunnel barrier layer.

### Claim 7 (depends on 1)

The magnetoresistive effect element according to claim 1, wherein the thickness of the first cap layer is 0.5 nm or less.

### Claim 8 (depends on 1)

The magnetoresistive effect element according to claim 1, wherein a cap layer including the first cap layer, the second cap layer, and the ferromagnetic layer does not exhibit a magneto-resistive effect.

### Claim 9 (depends on 1)

The magnetoresistive effect element according to claim 1,
wherein the first cap layer includes an oxide of a first metal element;
wherein the tunnel barrier layer includes an oxide of a second metal element; and
wherein the first metal element and the second metal element are identical.

### Claim 10 (depends on 9)

The magnetoresistive effect element according to claim 9,
wherein the oxide of the first metal element is MgO; and
wherein the oxide of the second metal element is MgO.

### Claim 11 (depends on 1)

The magnetoresistive effect element according to claim 1,
wherein the first cap layer comprises a plurality of islands distributed two-dimensionally on the magnetization free layer.

### Claim 12 (depends on 1)

The magnetoresistive effect element according to claim 1,
wherein the first cap layer comprises a plurality of islands distributed two-dimensionally on the magnetization free layer; and
wherein the ferromagnetic layer fills a space between the islands.

### Claim 13 (depends on 1)

The magnetoresistive effect element of claim 1,
wherein the second cap layer comprises a nonmagnetic metal layer in contact with the ferromagnetic layer, and
wherein the nonmagnetic metal layer comprises at least one element selected from the group consisting of Ru, Mo, and W.

### Claim 14 (depends on 13)

The magnetoresistive effect element according to claim 13, wherein the nonmagnetic metal layer comprises a plurality of metal layers.

### Claim 15 (depends on 13)

The magnetoresistive effect element according to claim 13, further comprising a hard mask layer in contact with the nonmagnetic metal layer, wherein the hard mask layer comprises at least one of Ta and W.

### Claim 16 (depends on 1)

The magnetoresistive effect element according to claim 1, further comprising:
a first electrode;
a base layer provided between the first electrode and the reference layer; and
a second electrode provided on the second cap layer.

### Claim 17 (depends on 16)

The magnetoresistive effect element according to claim 16,
wherein the reference layer includes:
a first ferromagnetic layer;
a second ferromagnetic layer;
a nonmagnetic layer interposed between the first ferromagnetic layer and the second ferromagnetic layer;
wherein the tunnel barrier layer includes MgO;
wherein the first cap layer includes MgO; and
wherein the second cap layer includes a nonmagnetic metal layer.

### Claim 18 (depends on 17)

The magnetoresistive effect element according to claim 17,
wherein the base layer comprises:
a first Ta-containing layer provided on the first electrode;
a Ti-containing layer provided on the first Ta-containing layer; and
a second Ta-containing layer provided on the Ti-containing layer.

### Claim 19 (depends on 18)

The magnetoresistive effect element according to claim 18,
wherein the base layer comprises:
a metal layer provided on the second Ta-containing layer; and
a NiCr layer provided on the metal layer.

### Claim 20

A magnetic memory comprising a plurality of magnetoresistive effect elements,
wherein each of the magnetoresistive effect elements comprises:
a reference layer;
a magnetization free layer;
a tunnel barrier layer provided between the reference layer and the magnetization free layer;
a first cap layer provided on the magnetization free layer;
a second cap layer; and
a ferromagnetic layer provided between the first cap layer and the second cap layer, the ferromagnetic layer having a thickness less than a thickness of the magnetization free layer.