Magnetoresistive stack with seed region and method of manufacturing the same

Patent metadata

Field	Value
Publication number	US-10692926-B2
Application number	US-201916601848-A
Country	US
Kind code	B2
Filing date	Oct 15, 2019
Priority date	Dec 10, 2015
Publication date	Jun 23, 2020
Grant date	Jun 23, 2020

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:
a seed region disposed at least partially on an electrically conductive material, wherein the seed region includes:
a plurality of alloy layers, wherein each alloy layer of the plurality of alloy layers includes nickel and chromium; and
a plurality of auxiliary layers;

a fixed magnetic region disposed above the seed region, wherein the fixed magnetic region includes a synthetic antiferromagnetic structure comprising:
a first ferromagnetic region disposed above the seed region;
a coupling layer disposed on and in contact with the first ferromagnetic region; and
a second ferromagnetic region disposed on and in contact with the coupling layer;

one or more dielectric layers disposed on and in contact with the second ferromagnetic region; and
a free magnetic region disposed above the one or more dielectric layers.

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 2 , wherein the fixed magnetic region is disposed on an auxiliary layer of the plurality of auxiliary layers.

4. The magnetoresistive stack of claim 1 , wherein at least one alloy layer of the plurality of alloy layers has a combined nickel content and chromium content of at least 99 atomic percent.

5. The magnetoresistive stack of claim 1 , wherein each alloy layer of the plurality of alloy layers has a thickness of 10 Å to 25 Å.

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

7. The magnetoresistive stack of claim 1 , further comprising a dusting layer disposed between the seed region and the fixed magnetic region, wherein the dusting layer includes at least one of molybdenum, magnesium, iron, platinum, ruthenium, an alloy including cobalt and iron, or combinations thereof.

8. The magnetoresistive stack of claim 7 , wherein the dusting layer has a thickness of 1 Å to 12 Å.

9. The magnetoresistive stack of claim 1 , wherein an alloy layer of the plurality of alloy layers includes at least 30 atomic percent chromium.

10. The magnetoresistive stack of claim 1 , wherein an auxiliary layer of the plurality of auxiliary layers is disposed at least partially on the electrically conductive material.

11. A magnetoresistive stack comprising:
a seed region disposed at least partially on an electrically conductive material, wherein the seed region includes:
at least one alloy layer, wherein the at least one alloy layer includes nickel and chromium and the content of other elements in the at least one alloy layer is less than or equal to 1 atomic percent; and
at least one auxiliary layer;

a dusting layer disposed on the seed region, wherein the dusting layer comprises molybdenum, magnesium, iron, platinum, ruthenium, an alloy including cobalt and iron, or a combination thereof;
a fixed magnetic region disposed above the dusting layer, wherein the fixed magnetic region includes a synthetic antiferromagnetic structure comprising:
a first ferromagnetic region disposed above the dusting layer;
a coupling layer disposed on and in contact with the first ferromagnetic region; and
a second ferromagnetic region disposed on and in contact with the coupling layer;

one or more dielectric layers disposed on and in contact with the second ferromagnetic region; and
a free magnetic region disposed above the one or more dielectric layers.

12. The magnetoresistive stack of claim 11 , wherein the at least one alloy layer is a first alloy layer and the seed region further comprises a second alloy layer.

13. The magnetoresistive stack of claim 11 , wherein the at least one auxiliary layer is a first auxiliary layer and the seed region further comprises a second auxiliary layer.

14. The magnetoresistive stack of claim 11 , wherein the at least one alloy layer has a thickness of 10 Å to 25 Å; and
the dusting layer has a thickness of 1 Å to 12 Å.

15. The magnetoresistive stack of claim 11 , wherein the at least one alloy layer includes greater than or equal to 30 atomic percent chromium.

16. The magnetoresistive stack of claim 11 , wherein the dusting layer includes an alloy including cobalt, iron, and boron.

17. The magnetoresistive stack of claim 11 , wherein the first ferromagnetic region comprises at least one of nickel, cobalt, or platinum.

18. The magnetoresistive stack of claim 11 , wherein the at least one auxiliary layer is disposed at least partially on the electrically conductive material.

19. The magnetoresistive stack of claim 11 , wherein the dusting layer is in contact with the seed region and the fixed magnetic region.

20. The magnetoresistive stack of claim 19 , wherein the dusting layer is in contact with the at least one alloy layer of the seed region.

Assignees

• Everspin Technologies Inc

Inventors

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

Classifications

• G11B5/3909 Primary

  Arrangements using a magnetic tunnel junction · CPC title

• H10N50/85

  Materials of the active region · CPC title

• H10B61/00 Primary

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

• H10N50/80

  Constructional details · CPC title

• H10N50/10

  Magnetoresistive devices · CPC title