Magnetoresistive stack, seed region thereof and method of manufacturing same

Patent metadata

Field	Value
Publication number	US-10141498-B2
Application number	US-201615373880-A
Country	US
Kind code	B2
Filing date	Dec 9, 2016
Priority date	Dec 10, 2015
Publication date	Nov 27, 2018
Grant date	Nov 27, 2018

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 method of manufacturing a magnetoresistive stack comprising:
depositing a seed region on an electrically conductive material, wherein depositing the seed region includes:
depositing an alloy including nickel and chromium having a thickness greater than or equal to 40 Angstroms and a material composition of chromium in the range of 25-60% by atomic percent;

depositing a fixed magnetic region on and in direct contact with the seed region, wherein depositing the fixed magnetic region includes:
depositing a multilayer unpinned, fixed synthetic antiferromagnetic structure including (i) depositing a first ferromagnetic structure on and in direct contact with the seed region, (ii) depositing a coupling material on and in direct contact with the first ferromagnetic structure, and (iii) depositing a second ferromagnetic structure on and in direct contact with the coupling material,
depositing a transition layer on and in direct contact with the second ferromagnetic structure, wherein the transition layer includes a non-ferromagnetic transition metal, and
forming a high-iron alloy interface region over the transition layer, wherein the high-iron alloy interface region has at least 50% iron by atomic composition;

depositing one or more dielectric layers wherein, after annealing, the one or more dielectric layers are on and in direct contact with the high-iron alloy interface region of the fixed magnetic region; and
depositing a free magnetic region over the one or more dielectric layers.

2. The method of claim 1 wherein depositing the alloy including nickel and chromium of the seed region includes depositing an alloy including nickel and chromium having:
a thickness greater than or equal to 50 Angstroms and less than or equal to 100 Angstroms, and
a material composition of chromium in the range of 30-50% by atomic percent.

3. The method of claim 1 wherein depositing the first ferromagnetic structure of the multilayer unpinned, fixed synthetic antiferromagnetic structure of the fixed magnetic region includes depositing a plurality of layers of at least two of cobalt, nickel and platinum.

4. The method of claim 1 wherein depositing the first ferromagnetic structure of the multilayer unpinned, fixed synthetic antiferromagnetic structure of the fixed magnetic region on and in direct contact with the seed region includes depositing alternating layers of nickel and cobalt including a layer of nickel on and in direct contact with the seed region.

5. The method of claim 1 wherein depositing the first ferromagnetic structure of the multilayer unpinned, fixed synthetic antiferromagnetic structure of the fixed magnetic region on and in direct contact with the seed region includes depositing alternating layers of cobalt and platinum including a layer of cobalt on and in direct contact with the seed region.

6. The method of claim 1 wherein depositing the alloy including nickel and chromium of the seed region includes depositing an alloy including nickel and chromium having a thickness greater than or equal to 60 Angstroms.

7. The method of claim 1 wherein depositing the alloy including nickel and chromium of the seed region includes depositing an alloy including nickel and chromium having a thickness greater than or equal to 50 Angstroms and less than or equal to 100 Angstroms.

8. The method of claim 1 wherein depositing the alloy including nickel and chromium of the seed region includes depositing an alloy including nickel and chromium having a material composition of chromium in the range of 30-50% by atomic percent.

9. The method of claim 1 wherein depositing the coupling material includes depositing ruthenium having of thickness of 4 Angstroms.

10. A magnetoresistive stack comprising:
a seed region disposed on an electrically conductive material, wherein the seed region includes an alloy including nickel and chromium having a thickness greater than or equal to 40 Angstroms and a material composition of chromium in the range of 25-60% by atomic percent;
a fixed magnetic region disposed on and in direct contact with the seed region, wherein the fixed magnetic region includes a multilayer unpinned, fixed synthetic antiferromagnetic structure including:
a first ferromagnetic structure on and in direct contact with the seed region,
a coupling layer on and in direct contact with the first ferromagnetic structure, and
a second ferromagnetic structure on and in direct contact with the coupling layer;
a transition layer on and in direct contact with the second ferromagnetic structure, wherein the transition layer includes a non-ferromagnetic transition metal, and
a high-iron alloy interface region disposed over the transition layer, wherein the high-iron alloy interface region includes at least 50% iron by atomic composition;

one or more dielectric layers disposed on and in direct contact with the high-iron alloy interface region of the fixed magnetic region; and
a free magnetic region disposed over the one or more dielectric layers.

11. The magnetoresistive stack of claim 10 wherein the first ferromagnetic structure of the multilayer unpinned, fixed synthetic antiferromagnetic structure of the fixed magnetic region includes a plurality of layers of magnetic material including at least two of cobalt, nickel and platinum.

12. The magnetoresistive stack of claim 10 wherein the first ferromagnetic structure of the multilayer unpinned, fixed synthetic antiferromagnetic structure of the fixed magnetic region includes alternating layers of nickel and cobalt including a first layer of nickel disposed on and in direct contact with the seed region.

13. The magnetoresistive stack of claim 10 wherein the first ferromagnetic structure of the multilayer unpinned, fixed synthetic antiferromagnetic structure of the fixed magnetic region includes alternating layers of platinum and cobalt including a first layer of cobalt disposed on and in direct contact with the seed region.

14. The magnetoresistive stack of claim 10 wherein the alloy including nickel and chromium of the seed region includes an alloy of nickel and chromium having a thickness greater than or equal to 60 Angstroms.

15. The magnetoresistive stack of claim 10 wherein the alloy including nickel and chromium of the seed region includes an alloy of nickel and chromium having a thickness greater than or equal to 50 Angstroms and less than or equal to 100 Angstroms.

16. The magnetoresistive stack of claim 15 wherein the alloy including nickel and chromium of the seed region includes nickel and chromium having a material composition of chromium in the range of 30-50% by atomic percent.

17. The magnetoresistive stack of claim 10 wherein the coupling material is ruthenium having of thickness of 4 Angstroms.

18. A magnetoresistive stack comprising:
an electrically conductive material disposed over a substrate;
a seed region disposed on and in direct contact with the electrically conductive material, wherein the seed region is an alloy including nickel and chromium having:
a thickness that is greater than or equal to 40 Angstroms and less than or equal to 100 Angstroms, and
a material composition of chromium in the range of 30-50% by atomic percent;

a fixed magnetic region disposed on and in direct contact with the seed region, wherein the fixed magnetic region includes:
an unpinned, fixed synthetic antiferromagnetic structure including:
a first plurality of ferromagnetic layers including a first ferromagnetic layer which is disposed on and in direct contact with the seed region,

Assignees

• Everspin Technologies Inc

Inventors

• Whig Renu
• Slaughter Jon M
• Chia Han-Jong

Classifications

• H01L43/10

  Electricity · mapped topic

• H01L43/12

  Electricity · mapped topic

• H01L43/02 Primary

  Electricity · mapped topic

• H01L43/08

  Electricity · mapped topic

• H10N50/85

  Materials of the active region · CPC title