Magnetoresistive stack with seed region and method of manufacturing the same

Patent metadata

Field	Value
Publication number	US-12089418-B2
Application number	US-202318185725-A
Country	US
Kind code	B2
Filing date	Mar 17, 2023
Priority date	Dec 10, 2015
Publication date	Sep 10, 2024
Grant date	Sep 10, 2024

Abstract

A magnetoresistive stack/structure and method of manufacturing same comprising wherein the stack/structure includes a seed region, a fixed magnetic region disposed on and in contact with the seed region, a dielectric layer(s) disposed on the fixed magnetic region and a free magnetic region disposed on the dielectric layer(s). In one embodiment, the seed region comprises an alloy including nickel and chromium having (i) a thickness greater than or equal to 40 Angstroms (+/−10%) and less than or equal to 60 Angstroms (+/−10%), and (ii) a material composition or content of chromium within a range of 25-60 atomic percent (+/−10%) or 30-50 atomic percent (+/−10%).

First claim

What is claimed is:

1. A magnetoresistive stack comprising:
an electrically conductive material;
a seed region disposed above the electrically conductive material, wherein the seed region includes tantalum and chromium, and wherein the proportion of chromium is large enough to render the seed region substantially non-magnetic;
a fixed magnetic region disposed above the seed region, wherein the fixed magnetic region includes a synthetic antiferromagnetic structure comprising a first ferromagnetic region, a coupling layer, and a second ferromagnetic region, and wherein the first ferromagnetic region and the second ferromagnetic region comprise same materials;
a first dielectric layer disposed above at least a portion of the fixed magnetic region;
a free magnetic region disposed above the first dielectric layer;
a second dielectric layer disposed above the free magnetic region; and
a third magnetic region disposed above the second dielectric layer.

2. The magnetoresistive stack of claim 1 , wherein the fixed magnetic region is disposed on and in contact with the seed region.

3. The magnetoresistive stack of claim 1 , wherein the seed region further comprises iron, cobalt, palladium, platinum, nickel, ruthenium, tungsten, molybdenum, an alloy including: iron and boron, an alloy including: cobalt, iron, and boron, or a combination thereof.

4. The magnetoresistive stack of claim 1 , wherein the seed region has a thickness greater than or equal to approximately 30 Å.

5. The magnetoresistive stack of claim 1 , wherein:
the first ferromagnetic region is disposed above the seed region and includes cobalt, iron, and boron;
the coupling layer is disposed on and in contact with the first ferromagnetic region; and
the second ferromagnetic region is disposed on and in contact with the coupling layer and below the first dielectric layer, the second ferromagnetic region including cobalt, iron, and boron.

6. The magnetoresistive stack of claim 1 , wherein the second dielectric layer is in contact with the free magnetic region, and wherein the third magnetic region comprises iron and cobalt.

7. The magnetoresistive stack of claim 6 , further comprising a spacer region disposed above the third magnetic region.

8. The magnetoresistive stack of claim 1 , further comprising a spacer region disposed above the third magnetic region, wherein the spacer region comprises ruthenium.

9. The magnetoresistive stack of claim 1 , further comprising a spacer region disposed above the third magnetic region, wherein the spacer region comprises ruthenium, wherein the electrically conductive material is a first electrically conductive material, and the magnetoresistive stack further comprises a second electrically conductive material disposed above the spacer region, wherein the second electrically conductive material comprises tantalum.

10. A magnetoresistive stack comprising:
an electrically conductive material;
a seed region disposed above the electrically conductive material, wherein the seed region comprises one or more of nickel, chromium, or ruthenium, and wherein the proportion of chromium, when included in the seed region, is large enough to render the seed region substantially non-magnetic;
a fixed magnetic region disposed above the seed region, wherein the fixed magnetic region includes a synthetic antiferromagnetic structure that includes at least two ferromagnetic regions separated by a coupling layer, wherein each of the at least two ferromagnetic regions comprises cobalt, iron, and boron;
a first dielectric layer disposed above at least a portion of the fixed magnetic region;
a free magnetic region disposed above the first dielectric layer;
a second dielectric layer disposed above the free magnetic region; and
a third magnetic region disposed above the second dielectric layer.

11. The magnetoresistive stack of claim 10 , wherein the seed region has a thickness greater than or equal to approximately 30 Å.

12. The magnetoresistive stack of claim 10 , wherein the fixed magnetic region is disposed on and in contact with the seed region.

13. The magnetoresistive stack of claim 10 , wherein the third magnetic region comprises iron and cobalt, and
wherein the at least two ferromagnetic regions include a first ferromagnetic region and a second ferromagnetic region;
wherein the first ferromagnetic region is disposed above the seed region;
wherein the coupling layer is disposed on and in contact with the first ferromagnetic region; and
wherein the second ferromagnetic region is disposed on and in contact with the coupling layer and below the first dielectric layer.

14. A magnetoresistive stack comprising:
an electrically conductive material;
a seed region disposed above the electrically conductive material, wherein the seed region comprises tantalum and one or more of: nickel, chromium, ruthenium, iron, cobalt, palladium, platinum, tungsten, or molybdenum, and wherein the proportion of chromium, when included in the seed region, is large enough to render the seed region substantially non-magnetic;
a fixed magnetic region disposed above the seed region, wherein the fixed magnetic region includes a synthetic antiferromagnetic structure comprising a first ferromagnetic region, a coupling layer, and a second ferromagnetic region, wherein the first ferromagnetic region includes cobalt, iron, and boron, and wherein the second ferromagnetic region includes cobalt, iron, and boron;
a dielectric layer disposed above at least a portion of the fixed magnetic region;
a free magnetic region disposed above the dielectric layer; and
a third magnetic region disposed above the free magnetic region.

15. The magnetoresistive stack of claim 14 , wherein the fixed magnetic region is disposed on and in contact with the seed region.

16. The magnetoresistive stack of claim 14 , wherein the dielectric layer is a first dielectric layer, and the magnetoresistive stack further comprises a second dielectric layer disposed above the free magnetic region.

17. The magnetoresistive stack of claim 14 , wherein:
the first ferromagnetic region is disposed above the seed region;
the coupling layer is disposed on and in contact with the first ferromagnetic region; and
the second ferromagnetic region is disposed on and in contact with the coupling layer.

18. The magnetoresistive stack of claim 14 , further comprising a spacer region disposed above the free magnetic region, wherein the spacer region comprises ruthenium, and
wherein the third magnetic region comprises iron and cobalt.

19. The magnetoresistive stack of claim 14 , wherein the electrically conductive material is a first electrically conductive material, and the magnetoresistive stack further comprises a second electrically conductive material disposed above the free magnetic region, wherein the second electrically conductive material comprises tantalum.

20. The magnetoresistive stack of claim 14 , wherein the seed region has a thickness greater than or equal to approximately 30 Å.

Assignees

• Everspin Technologies Inc

Inventors

• Sun Jijun
• Aggarwal Sanjeev
• Chia Han-Jong
• Slaughter Jon M
• Whig Renu

Classifications

• H10N50/85

  Materials of the active region · CPC title

• H10N50/80

  Constructional details · CPC title

• H10N50/10

  Magnetoresistive devices · CPC title

• H10N50/01

  Manufacture or treatment · CPC title

• G11B5/3909 Primary

  Arrangements using a magnetic tunnel junction · CPC title