Magnetoresistive stack with seed region and method of manufacturing the same

Patent metadata

Field	Value
Publication number	US-10483320-B2
Application number	US-201816195178-A
Country	US
Kind code	B2
Filing date	Nov 19, 2018
Priority date	Dec 10, 2015
Publication date	Nov 19, 2019
Grant date	Nov 19, 2019

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 an alloy layer including at least 99 atomic percent (at. %) of nickel and chromium and comprises:
a first alloy layer including nickel and chromium in contact with the electrically conductive material;
a second alloy layer including nickel and chromium in contact with a fixed magnetic region; and
at least one auxiliary layer disposed between the first alloy layer and the second alloy layer;

the fixed magnetic region disposed at least partially on and in contact with the seed region, wherein the fixed magnetic region includes a synthetic antiferromagnetic structure comprising:
a first ferromagnetic region disposed on and in contact with 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 on the one or more dielectric layers.

2. The magnetoresistive stack of claim 1 , wherein the alloy layer includes at least 30 at. % chromium (Cr).

3. The magnetoresistive stack of claim 1 , wherein the seed region further includes at least one auxiliary layer.

4. The magnetoresistive stack of claim 1 , wherein the alloy layer is in contact with the electrically conductive material.

5. The magnetoresistive stack of claim 1 , wherein the seed region further includes at least one auxiliary layer in contact with the electrically conductive material.

6. The magnetoresistive stack of claim 1 , wherein the seed region further includes at least one auxiliary layer in contact with the electrically conductive material, and wherein the auxiliary layer has a same composition as a composition of the electrically conductive material.

7. The magnetoresistive stack of claim 1 , wherein the seed region further includes at least one auxiliary layer, and wherein the alloy layer is in contact with the fixed magnetic region.

8. The magnetoresistive stack of claim 1 , wherein the seed region further includes at least one auxiliary layer in contact with the fixed magnetic region.

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

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

11. A magnetoresistive stack comprising:
a seed region disposed at least partially on an electrically conductive material, wherein the seed region includes:
a first alloy layer including nickel and chromium in contact with the electrically conductive material;
a second alloy layer including nickel and chromium in contact with a dusting layer; and
at least one auxiliary layer disposed between the first alloy layer and the second alloy layer;

the dusting layer disposed on the seed region, wherein the dusting layer includes at least one of molybdenum, magnesium, iron, platinum, ruthenium, or an alloy including cobalt and iron;
a fixed magnetic region disposed on and in contact with the dusting layer, wherein the fixed magnetic region comprises:
a first ferromagnetic region disposed on and in contact with 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 on the one or more dielectric layers.

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

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

14. The magnetoresistive stack of claim 11 , wherein the seed region comprises an alloy layer including nickel and at least 30 atomic percent (at. %) chromium.

15. The magnetoresistive stack of claim 11 , wherein the seed region comprises an alloy layer including at least 99 atomic percent (at. %) of nickel and chromium.

16. The magnetoresistive stack of claim 11 , wherein the dusting layer has a thickness of 1 Å to 12Å.

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 coupling layer includes ruthenium.

19. A method of manufacturing a magnetoresistive stack, the method comprising:
depositing a seed region, including:
depositing a first alloy layer including nickel and chromium;
depositing a second alloy layer including nickel and chromium in contact with a fixed magnetic region; and
depositing at least one auxiliary layer disposed between the first alloy layer and the second alloy layer;

depositing a dusting layer of at least one of molybdenum, magnesium, iron, platinum, or ruthenium on and in contact with the seed region;
depositing the fixed region including a synthetic antiferromagnetic structure on and in contact with the dusting layer, wherein depositing the synthetic antiferromagnetic structure comprises:
depositing a first ferromagnetic region on and in contact with the dusting layer;
depositing a coupling layer on and in contact with the first ferromagnetic region; and
depositing a second ferromagnetic region on and in contact with the coupling layer;
depositing one or more dielectric layers on the second ferromagnetic region; and
depositing a free magnetic region on the one or more dielectric layers.

20. The method of claim 19 , wherein depositing a first alloy layer, a second alloy layer, or both, comprises:
depositing at least one alloy layer including at least 99 atomic percent (at. %) of nickel and chromium.

21. The method of claim 19 , further comprising:
depositing a reference layer on and in contact with the synthetic antiferromagnetic structure.

Assignees

• Everspin Technologies Inc

Inventors

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

Classifications

• G11C11/1673

  Reading or sensing circuits or methods · CPC title

• G11B5/3909 Primary

  Arrangements using a magnetic tunnel junction · CPC title

• H01L27/222 Primary

  Electricity · mapped topic

• H01L43/10

  Electricity · mapped topic

• H01L43/08

  Electricity · mapped topic