# US 2013/0154034 A1 · Method and system for setting a pinned layer in a magnetic tunneling junction

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- Number: US 2013/0154034 A1
- Document ID: US20130154034A1
- Status: Published application
- Kind: A1
- Application number: 13/332,093
- Filed: 2011-12-20
- Published: 2013-06-20
- Earliest claimed: 2011-12-20
- Assignees: Samsung Electronics Co., Ltd.
- Inventors: Dmytro Apalkov; Alexey Vasilyevitch Khvalkovskiy; Vladimir Nikitin; Mohamad Towfik Krounbi; Xueti Tang; Se Chung Oh; Woo Chang Lim; Jang Eun Lee; Ki Woong Kim; Kyoung Sun Kim
- Web page: https://patentgrep.com/patent/US20130154034A1

## CPC

- H10N 50/10: Magnetoresistive devices
- G11C 11/161: {details concerning the memory cell structure, e.g. the layers of the ferromagnetic memory cell}
- G11C 11/1673: {Reading or sensing circuits or methods}
- G11C 11/1675: {Writing or programming circuits or methods}
- H10N 50/01: Manufacture or treatment
- H10N 50/85: Materials of the active region
- H10B 61/22: {of the field-effect transistor [FET] type}
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- G11C: STATIC STORES (semiconductor memory devices H10B)
- H10B: ELECTRONIC MEMORY DEVICES

## Abstract

A method and system for setting the direction of pinned layers in a magnetic junction are described. In one aspect, a magnetic field greater than the coercivity of the layers in a pinned layer but less than the coupling field between the layers is applied. In another aspect the pinned layers are switched from an anti-dual state to a dual state using a spin transfer torque current. In another aspect, a magnetic junction having a partial perpendicular anisotropy (PPMA) layer in the pinned layer is provided. In some aspects, the PPMA layer is part of a synthetic antiferromagnetic structure. In some embodiments, a decoupling layer is provided between the PPMA layer and another ferromagnetic layer in the pinned layer.

## Claims

### Claim 1

A method for setting a reference layer of a pinned layer in magnetic junction including a free layer, a nonmagnetic spacer layer, and the pinned layer, the nonmagnetic spacer layer residing between the pinned layer and the free layer, the pinned layer including a plurality of ferromagnetic layers interleaved with at least one spacer layer, the plurality of ferromagnetic layers having at least one easy axis, the method comprising:
applying a magnetic field in a direction parallel to an easy axis of the at least one easy axis, the magnetic field having a magnitude greater than a coercivity of each of the plurality of layers and less than a coupling field between a portion of the plurality of layers.

### Claim 2 (depends on 1)

The method of claim 1 wherein a ferromagnetic layer of the plurality of ferromagnetic layers has a saturation magnetic moment greater than any saturation magnetic moment of any remaining layer of the plurality of ferromagnetic layers and wherein the direction is parallel to the easy axis for the ferromagnetic layer.

### Claim 3 (depends on 2)

The method of claim 2 wherein the ferromagnetic layer is a ferromagnetic pinned layer.

### Claim 4 (depends on 2)

The method of claim 2 wherein the ferromagnetic layer is a reference layer.

### Claim 5 (depends on 1)

The method of claim 1 wherein the magnetic junction includes an additional nonmagnetic spacer layer and an additional pinned layer, the additional nonmagnetic spacer layer residing between the free layer and the additional pinned layer.

### Claim 6 (depends on 1)

The method of claim 1 wherein the nonmagnetic spacer layer is a tunneling barrier layer.

### Claim 7 (depends on 1)

The method of claim 1 wherein the direction is perpendicular to plane.

### Claim 8

A method for setting a first pinned layer in magnetic junction including the first pinned layer, a first nonmagnetic spacer layer, a free layer, a second nonmagnetic spacer layer, and a second pinned layer, the first nonmagnetic spacer layer being between the first pinned layer and the free layer, the second nonmagnetic spacer layer residing between the second pinned layer and the free layer, the first pinned layer having at least one easy axis, the first pinned layer and the second pinned layer being in an anti-dual state, the first pinned layer having a first coercivity, the second pinned layer having a second coercivity greater than the first coercivity, the method comprising:
switching the first pinned layer using a spin transfer current driven through the magnetic junction

### Claim 9 (depends on 8)

The method of claim 8 wherein the spin transfer current is applied from the second pinned layer to the first pinned layer.

### Claim 10 (depends on 8)

The method of claim 8 wherein the step of switching the first pinned layer further includes:
applying a magnetic field in addition to the spin transfer current, the magnetic field being in a direction configured to switch the first pinned layer to the anti-dual state.

### Claim 11 (depends on 10)

The method of claim 10 wherein the step of switching the first pinned layer further includes:
heating at least the first pinned layer.

### Claim 12 (depends on 8)

The method of claim 8 further comprising:
setting the first pinned layer and the second pinned layer in the anti-dual state before the step of switching the first pinned layer.

### Claim 13 (depends on 8)

The method of claim 8 wherein the first pinned layer includes a plurality of ferromagnetic layers interleaved with at least one nonmagnetic layer, and wherein the step of switching the first pinned layer further includes:
switching one of the plurality of ferromagnetic layers closest to the free layer.

### Claim 14

A magnetic junction comprising:
a free layer;
a nonmagnetic spacer layer;
a pinned layer, the nonmagnetic spacer layer residing between the pinned layer and the free layer, the pinned layer including at least one partial perpendicular magnetic anisotropy (PPMA) layer.

### Claim 15 (depends on 14)

The magnetic junction of claim 14 wherein the at least one PPMA layer adjoins the nonmagnetic spacer layer.

### Claim 16 (depends on 15)

The magnetic junction of claim 15 wherein the pinned layer is a synthetic antiferromagnetic structure including a plurality of ferromagnetic layers interleaved with at least one nonmagnetic layer and wherein the at least one PPMA adjoins a ferromagnetic layer of the plurality of ferromagnetic layers closest to the free layer.

### Claim 17 (depends on 15)

The magnetic junction of claim 15 wherein the pinned layer is a synthetic antiferromagnetic structure including a plurality of ferromagnetic layers interleaved with at least one nonmagnetic layer and wherein a ferromagnetic layer of the plurality of ferromagnetic layers closest to the free layer is the at least one PPMA layer.

### Claim 18 (depends on 15)

The magnetic junction of claim 15 further wherein the free layer includes an additional PPMA layer.

### Claim 19 (depends on 15)

The magnetic junction of claim 15 further comprising
an additional pinned layer; and
an additional spacer layer between the free layer and the additional pinned layer.

### Claim 20 (depends on 19)

The magnetic junction of claim 19 wherein the additional pinned layer includes an additional PPMA layer adjoining the additional spacer layer.

### Claim 21 (depends on 20)

The magnetic junction of claim 20 wherein the additional pinned layer is a synthetic antiferromagnetic structure including a plurality of ferromagnetic layers interleaved with at least one spacer layer.

### Claim 22

A magnetic junction comprising:
a first pinned layer;
a first nonmagnetic spacer layer;
a free layer, the first nonmagnetic spacer layer being between the first pinned layer and the free layer;
a second nonmagnetic spacer layer;
a second pinned layer, the second nonmagnetic spacer layer residing between the second pinned layer and the free layer;
wherein at least one of the first pinned layer and the second pinned layer includes a plurality of ferromagnetic layers interleaved with at least one nonmagnetic layer, the plurality of ferromagnetic layers being ferromagnetically aligned, one of the ferromagnetic layers closest to the free layer being a partial perpendicular magnetic anisotropy (PPMA) layer.

### Claim 23 (depends on 22)

The magnetic junction of claim 22 wherein a nonmagnetic layer of the at least one nonmagnetic layer closest to the free layer is a decoupling layer, the decoupling layer being a seed layer for the PMA layer such that the PMA layer has a perpendicular anisotropy energy greater than an out-of-plane demagnetization energy.

### Claim 24 (depends on 23)

The magnetic junction of claim 23 wherein the decoupling layer includes Ta, Cr, Pd, Pt, Ti, W, Hf, Ge, Zr, Al, Mg, Ru or oxide or nitride of these materials.

### Claim 25

A method for providing a magnetic junction comprising:
providing a free layer;
providing a nonmagnetic spacer layer; and
providing a pinned layer, the nonmagnetic spacer layer residing between the pinned layer and the free layer, the pinned layer including at least one partial perpendicular magnetic anisotropy (PPMA) layer.

### Claim 26 (depends on 25)

The method of claim 25 wherein the at least one PPMA layer adjoins the nonmagnetic spacer layer.

### Claim 27 (depends on 26)

The method of claim 26 wherein the pinned layer is a synthetic antiferromagnetic structure including a plurality of ferromagnetic layers interleaved with at least one nonmagnetic layer and wherein the at least one PPMA adjoins a ferromagnetic layer of the plurality of ferromagnetic layers closest to the free layer.

### Claim 28 (depends on 26)

The method of claim 26 wherein the pinned layer is a synthetic antiferromagnetic structure including a plurality of ferromagnetic layers interleaved with at least one nonmagnetic layer and wherein a ferromagnetic layer of the plurality of ferromagnetic layers closest to the free layer is the at least one PPMA layer.

### Claim 29 (depends on 26)

The method of claim 26 further comprising:
providing an additional pinned layer; and
providing an additional spacer layer between the free layer and the additional pinned layer.

### Claim 30 (depends on 29)

The method of claim 29 wherein the additional pinned layer includes an additional PPMA layer adjoining the additional spacer layer.

### Claim 31 (depends on 30)

The method of claim 30 wherein the additional pinned layer is a synthetic antiferromagnetic structure including a plurality of ferromagnetic layers interleaved with at least one spacer layer.

### Claim 32 (depends on 25)

The method of claim 25 wherein the free layer includes an additional PPMA layer.

### Claim 33

A method for providing magnetic junction comprising:
providing a first pinned layer;
providing a first nonmagnetic spacer layer;
providing a free layer, the first nonmagnetic spacer layer being between the first pinned layer and the free layer;
providing a second nonmagnetic spacer layer;
providing a second pinned layer, the second nonmagnetic spacer layer residing between the second pinned layer and the free layer;
wherein at least one of the first pinned layer and the second pinned layer includes a plurality of ferromagnetic layers interleaved with at least one nonmagnetic layer, the plurality of ferromagnetic layers being ferromagnetically aligned, one of the ferromagnetic layers closest to the free layer being a partial perpendicular magnetic anisotropy (PPMA) layer.

### Claim 34 (depends on 33)

The method of claim 33 wherein a nonmagnetic layer of the at least one nonmagnetic layer closest to the free layer is a decoupling layer, the decoupling layer being a seed layer for the PMA layer such that the PMA layer has a perpendicular anisotropy energy greater than an out-of-plane demagnetization energy.

### Claim 35 (depends on 34)

The method of claim 34 wherein the decoupling layer includes Ta, Cr, Pd, Pt, Ti, W, Hf, Ge, Zr, Al, Mg, Ru or oxide or nitride of these materials.