Methods of forming perpendicular magnetoresistive elements using sacrificial layers

Patent metadata

Field	Value
Publication number	US-11805702-B2
Application number	US-202117313976-A
Country	US
Kind code	B2
Filing date	May 6, 2021
Priority date	May 6, 2021
Publication date	Oct 31, 2023
Grant date	Oct 31, 2023

Abstract

A perpendicular magnetoresistive element comprises (counting from the element bottom): a reference layer having magnetic anisotropy in a direction perpendicular to a film surface and having an invariable magnetization direction; a tunnel barrier layer; a crystalline recording layer having magnetic anisotropy in a direction perpendicular to a film surface and having a variable magnetization direction; an oxide buffer layer; and a cap layer, wherein the crystalline recording layer consists of a CoFe alloy that is substantially free of boron and has BCC (body-centered cubic) CoFe grains having epitaxial growth with (100) plane parallel to a film surface.

First claim

The invention claimed is:

1. A method of manufacturing a perpendicular magnetoresistive element (PME) comprising the steps of:
forming a reference layer having a magnetic anisotropy in a direction substantially perpendicular to a film surface and having an invariable magnetization direction;
forming a tunnel barrier layer atop the reference layer;
depositing a recording layer, atop the tunnel barrier layer, comprising a boron (B) alloy having at least one of iron (Fe) and cobalt (Co);
forming a buffer layer comprising an oxide layer atop the recording layer;
forming a sacrificial layer, atop the buffer layer, comprising a boron-absorbing composition;
conducting a plurality of thermal annealing processes to diffuse boron atoms of the recording layer through the buffer layer into the sacrificial layer, wherein, after the plurality of thermal annealing processes, the recording layer has a magnetic anisotropy in a direction substantially perpendicular to a film surface and having a variable magnetization direction;
removing the sacrificial layer or most of the sacrificial layer; and
forming a cap layer atop the buffer layer.

2. The element of claim 1 , wherein the tunnel barrier layer is made of MgO, MgZnO, MgZrO, or MgAlO.

3. The element of claim 1 , wherein, after depositing the recording layer, the recording layer comprises boron, in form(s) including but not limited to one or more of CoFeB, CoB and FeB, ideally with a ratio of boron between 10% and 30%.

4. The element of claim 1 , wherein, after depositing the recording layer, the recording layer is a tri-layer comprising a first magnetic alloy layer including at least one of CoFeB, CoFeB/CoFe, Fe/CoFeB, FeB/CoFeB and CoFe/CoFeB, a second magnetic alloy layer including at least one of CoFeB and CoB, an insertion layer provided between the first magnetic alloy layer and the second magnetic alloy layer and containing at least one element selected from the group consisting of Ta, Hf, Zr, Ti, Mg, Nb, W, Mo, Ru, Al, Cu, Si and having a thickness less than 0.5 nm.

5. The element of claim 1 , wherein the oxide layer is made of a metal oxide comprising at least one element selected from the group consisting of Mg, Ti, Ta, Na, Li, Ca, Zn, Zr, Cd, In, Sn, Ru, Al, Cu, Ag and Ni, and having a thickness less than 1.0 nm.

6. The element of claim 1 , wherein the buffer layer further comprises a metal material layer, atop the oxide layer, comprising at least one element selected from the group consisting of Pt, Ru, Rh, Pd, Ir, Ni, Cu, Ag, Au and alloy thereof, and having a thickness less than 0.5 nm.

7. The element of claim 1 , wherein the cap layer is a non-magnetic metal layer comprising at least one element selected from the group consisting of Pt, Ta, Hf, Zr, Ti, Mg, Nb, W, Mo, Ru, Ir, Al, Cu and alloy thereof, or non-magnetic nitride layer selected from the group consisting of AlN, NbN, ZrN, IrN, TaN, TiN, and SiN.

8. The element of claim 1 , wherein the boron-absorbing composition comprises Ta, Hf, Ti, V, Mo, W, Zr, Nb or alloy thereof.

9. The element of claim 1 , further comprising forming a protective layer between said forming the sacrificial layer and said conducting the thermal annealing process, wherein the protective layer is made of an oxidization-resistive alloy or a noble metal, preferred to be selected from the group consisting of Pt, Pd, Ru, Cu, Ag, Ir, Rh and Au.

10. The element of claim 1 , further comprising forming an oxidization process, between said removing the most of the sacrificial layer and said forming the cap layer, conducted by using of a mixed gas containing natural, or radical, or ionized oxygen and Argon (Ar) to oxidize the remained sacrificial layer.

11. A method of manufacturing a perpendicular magnetoresistive element (PME) comprising the steps of:
forming a reference layer having a magnetic anisotropy in a direction substantially perpendicular to a film surface and having an invariable magnetization direction;
forming a tunnel barrier layer atop the reference layer;
depositing a first recording layer, atop the tunnel barrier layer, comprising a boron (B) alloy having at least one of iron (Fe) and cobalt (Co);
forming a first buffer layer comprising a first oxide layer atop the first recording layer;
forming a first sacrificial layer, atop the first buffer layer, comprising a boron-absorbing composition;
conducting a first thermal annealing process to diffuse boron atoms of the first recording layer through the first buffer layer into the first sacrificial layer, wherein, after the first thermal annealing process, the first recording layer has a first magnetic anisotropy in a direction substantially perpendicular to a film surface and having a variable magnetization direction;
removing the first sacrificial layer or most of the first sacrificial layer;
depositing a second recording layer, atop the first buffer, comprising a boron (B) alloy having at least one of iron (Fe) and cobalt (Co);
forming a second buffer layer comprising a second oxide layer atop the second recording layer;
forming a second sacrificial layer, atop the second buffer layer, comprising a boron-absorbing composition;
conducting a second thermal annealing process to diffuse boron atoms of the second recording layer through the second buffer layer into the second sacrificial layer, wherein, after the second thermal annealing process, the second recording layer has a second magnetic anisotropy in a direction substantially perpendicular to a film surface and having a variable magnetization direction;
removing the second sacrificial layer or most of the second sacrificial layer; and
forming a cap layer atop the second buffer layer.

12. The element of claim 11 , wherein the tunnel barrier layer is made of MgO, MgZnO, MgZrO, or MgAlO.

13. The element of claim 11 , wherein, after depositing each of the first recording layer and the second recording layer, each of the first recording layer and the second recording layer comprises boron, in form(s) including but not limited to one or more of CoFeB, CoB and FeB, ideally with a ratio of boron between 10% and 30%.

14. The element of claim 11 , wherein, after depositing each of the first recording layer and the second recording layer, at least one of the first recording layer and the second recording layer is a tri-layer comprising a first magnetic alloy layer including at least one of CoFeB, CoFeB/CoFe, Fe/CoFeB, FeB/CoFeB and CoFe/CoFeB, a second magnetic alloy layer including at least one of CoFeB and CoB, an insertion layer provided between the first magnetic alloy layer and the second magnetic alloy layer and containing at least one element selected from the group consisting of Ta, Hf, Zr, Ti, Mg, Nb, W, Mo, Ru, Al, Cu, Si and having a thickness less than 0.5 nm.

15. The element of claim 11 , wherein each of the first oxide layer and the second oxide layer is made of a metal oxide comprising at least one element selected from the group consisting of Mg, Ti, Ta, Na, Li, Ca, Zn, Zr, Cd, In, Sn, Ru, Al, Cu, Ag and Ni, and having a thickness less than 1.0 nm.

16. The element of claim 11 , wherein each of the first buffer layer and the second buffer layer further comprises a metal material layer, atop each of the first oxide layer and the second oxide layer, comprising at least one element selected from the group consisting of Pt, Ru, Rh, Pd, Ir, Ni, Cu, Ag, Au and alloy thereof, and having a thickness less than 0.5 nm.

17. The element of claim 11 , wherein the cap layer is a non-magnetic metal layer comprising at least one element selected from the group consisting of Pt, Ta, Hf, Zr,

Assignees

• Guo Yimin
• Xiao Rongfu
• Chen Jun

Inventors

• Guo Yimin
• Xiao Rongfu
• Chen Jun

Classifications

• H10N50/85

  Materials of the active region · CPC title

• H10N50/01 Primary

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• G11C11/161 Primary

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• H01F10/3286

  Spin-exchange coupled multilayers having at least one layer with perpendicular magnetic anisotropy · CPC title

• H10B61/00

  Magnetic memory devices, e.g. magnetoresistive RAM [MRAM] devices · CPC title