# US 2021/0082999 A1 · Magnetoresistive memory device

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- Number: US 2021/0082999 A1
- Document ID: US20210082999A1
- Status: Published application
- Kind: A1
- Application number: 16/816,775
- Filed: 2020-03-12
- Published: 2021-03-18
- Earliest claimed: 2019-09-12
- Assignees: Kioxia Corporation
- Applicants: Kioxia Corporation
- Inventors: Masaru TOKO; Tadaomi DAIBOU; Junichi ITO; Taichi IGARASHI; Tadashi KAI
- Web page: https://patentgrep.com/patent/US20210082999A1

## CPC

- H10B 61/10: {comprising components having two electrodes, e.g. diodes or MIM elements}
- G11C 11/161: {details concerning the memory cell structure, e.g. the layers of the ferromagnetic memory cell}
- G11C 11/1653: {Address circuits or decoders}
- G11C 11/1657: {Word-line or row circuits}
- G11C 11/1659: {Cell access}
- H10N 50/10: Magnetoresistive devices
- H10N 50/80: Constructional details
- H10N 50/85: Materials of the active region
- H10N 50/01: Manufacture or treatment
- H10B: ELECTRONIC MEMORY DEVICES
- G11C: STATIC STORES (semiconductor memory devices H10B)
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR

## Abstract

A magnetoresistive memory device according to one embodiment includes: first and second layer stacks, each of which includes: a first ferromagnetic layer having a magnetization directed in a first direction; a non-magnetic first conductive layer above the first ferromagnetic layer, a second ferromagnetic layer provided above the first conductive layer and having a magnetization directed in a second direction different from the first direction, a first insulating layer on an upper surface of the second ferromagnetic layer, and a third ferromagnetic layer above the first insulating layer. The second ferromagnetic layer of the second layer stack is thicker than the second ferromagnetic layer of the first layer stack.

## Claims

### Claim 1

A magnetoresistive memory device, comprising:
a first layer stack and a second layer stack, wherein
each of the first layer stack and the second layer stack includes:
a first ferromagnetic layer having a magnetization directed in a first direction;
a non-magnetic first conductive layer above the first ferromagnetic layer,
a second ferromagnetic layer provided above the first conductive layer and having a magnetization directed in a second direction different from the first direction,
a first insulating layer on an upper surface of the second ferromagnetic layer, and
a third ferromagnetic layer above the first insulating layer, and
the second ferromagnetic layer of the second layer stack is thicker than the second ferromagnetic layer of the first layer stack.

### Claim 2 (depends on 1)

The device according to claim 1, wherein
the second ferromagnetic layer includes:
a fourth ferromagnetic layer provided between the first insulating layer and the first conductive layer and being in contact with the first insulating layer, and
a fifth ferromagnetic layer provided between the fourth ferromagnetic layer and the first conductive layer and having a crystal structure different from a crystal structure of the fourth ferromagnetic layer.

### Claim 3 (depends on 2)

The device according to claim 2, wherein
each of the fourth ferromagnetic layer of the first layer stack and the fourth ferromagnetic layer of the second layer stack has a thickness equal to or greater than 0.8 nm and equal to or smaller than 1.4 nm.

### Claim 4 (depends on 2)

The device according to claim 2, wherein
a film thickness of the fourth ferromagnetic layer is thinner than a film thickness of the fifth ferromagnetic layer.

### Claim 5 (depends on 2)

The device according to claim 2, wherein
the first ferromagnetic layer of the first layer stack is antiferromagnetically coupled with the fifth ferromagnetic layer of the first layer stack.

### Claim 6

A magnetoresistive memory device comprising:
first to n-th layer stacks, where n is a natural number equal to or greater than 2, wherein
a X-th layer stack is positioned above a (X−1)-th layer stack for all cases of X, where X is every natural number from 2 to n,
each of the first to n-th layer stacks includes:
a first ferromagnetic layer having a magnetization directed in a first direction;
a non-magnetic first conductive layer above the first ferromagnetic layer,
a second ferromagnetic layer provided above the first conductive layer and having a magnetization directed in a second direction different from the first direction,
a first insulating layer on an upper surface of the second ferromagnetic layer, and
a third ferromagnetic layer above the first insulating layer, and
for each of all cases of X being 2 to n, the second ferromagnetic layer of the X-th layer stack is thicker than the second ferromagnetic layer of the (X−1)-th layer stack.

### Claim 7 (depends on 6)

The device according to claim 6, wherein
the second ferromagnetic layer includes:
a fourth ferromagnetic layer provided between the first insulating layer and the first conductive layer and being in contact with the first insulating layer, and
a fifth ferromagnetic layer provided between the fourth ferromagnetic layer and the first conductive layer and having a crystal structure different from a crystal structure of the fourth ferromagnetic layer.

### Claim 8 (depends on 7)

The device according to claim 7, wherein
the fourth ferromagnetic layer of each of the first to n-th layer stacks has a thickness equal to or greater than 0.8 nm and equal to or smaller than 1.4 nm.

### Claim 9 (depends on 7)

The device according to claim 7, wherein
a film thickness of the fourth ferromagnetic layer is thinner than a film thickness of the fifth ferromagnetic layer.

### Claim 10 (depends on 7)

The device according to claim 7, wherein
the first ferromagnetic layer of the X-th layer stack is antiferromagnetically coupled with the fifth ferromagnetic layer of the X-th layer stack for all cases of X, where X is every natural number from 2 to n.

### Claim 11

A magnetoresistive memory device comprising:
a first layer stack and a second layer stack, wherein
each of the first layer stack and the second layer stack includes:
a first ferromagnetic layer having a magnetization directed in a first direction;
a non-magnetic first conductive layer above the first ferromagnetic layer,
a second ferromagnetic layer provided above the first conductive layer and having a magnetization directed in a second direction different from the first direction,
a first insulating layer on an upper surface of the second ferromagnetic layer, and
a third ferromagnetic layer above the first insulating layer, and
the first conductive layer of the second layer stack has a thickness different from the first conductive layer of the first layer stack.

### Claim 12 (depends on 11)

The device according to claim 11, wherein
the second ferromagnetic layer includes:
a fourth ferromagnetic layer provided between the first insulating layer and the first conductive layer and being in contact with the first insulating layer, and
a fifth ferromagnetic layer provided between the fourth ferromagnetic layer and the first conductive layer and having a crystal structure different from a crystal structure of the fourth ferromagnetic layer.

### Claim 13 (depends on 12)

The device according to claim 12, wherein
each of the first conductive layer of the first layer stack and the first conductive layer of the second layer stack has a thickness equal to or greater than 0.2 nm and equal to or smaller than 0.8 nm.

### Claim 14 (depends on 12)

The device according to claim 12, wherein
the first ferromagnetic layer of the first layer stack is antiferromagnetically coupled with the fifth ferromagnetic layer of the first layer stack.

### Claim 15 (depends on 11)

The device according to claim 11, wherein
each of the first conductive layer of the first layer stack and the first conductive layer of the second layer stack has a thickness equal to or greater than 0.2 nm and equal to or smaller than 0.8 nm.

### Claim 16

A magnetoresistive memory device comprising:
first to n-th layer stacks, where n is a natural number equal to or greater than 2, wherein
a X-th layer stack is positioned above a (X−1)-th layer stack for all cases of X, where X is every natural number from 2 to n,
each of the first to n-th layer stacks includes:
a first ferromagnetic layer having a magnetization directed in a first direction;
a non-magnetic first conductive layer above the first ferromagnetic layer,
a second ferromagnetic layer provided above the first conductive layer and having a magnetization directed in a second direction different from the first direction,
a first insulating layer on an upper surface of the second ferromagnetic layer, and
a third ferromagnetic layer above the first insulating layer, and
for each of all cases of X being 2 to n, the first conductive layer of the X-th layer stack is thicker than the first conductive layer of the (X−1)-th layer stack, or
for each of all cases of X being 2 to n, the first conductive layer of the X-th layer stack is thinner than the first conductive layer of the (X−1)-th layer stack.

### Claim 17 (depends on 16)

The device according to claim 16, wherein
the second ferromagnetic layer includes:
a fourth ferromagnetic layer provided between the first insulating layer and the first conductive layer and being in contact with the first insulating layer, and
a fifth ferromagnetic layer provided between the fourth ferromagnetic layer and the first conductive layer and having a crystal structure different from a crystal structure of the fourth ferromagnetic layer.

### Claim 18 (depends on 17)

The device according to claim 17, wherein
the first conductive layer of each of the first to n-th layer stacks has a thickness equal to or greater than 0.2 nm and equal to or smaller than 0.8 nm.

### Claim 19 (depends on 17)

The device according to claim 17, wherein
the first ferromagnetic layer of the X-th layer stack is antiferromagnetically coupled with the fifth ferromagnetic layer of the X-th layer stack for all cases of X, where X is every natural number from 2 to n.

### Claim 20 (depends on 16)

The device according to claim 16, wherein
the first conductive layer of each of the first to n-th layer stacks has a thickness equal to or greater than 0.2 nm and equal to or smaller than 0.8 nm.