Magnetoresistance element with an improved seed layer to promote an improved response to magnetic fields

Patent metadata

Field	Value
Publication number	US-9804234-B2
Application number	US-201514591213-A
Country	US
Kind code	B2
Filing date	Jan 7, 2015
Priority date	Jan 9, 2014
Publication date	Oct 31, 2017
Grant date	Oct 31, 2017

Abstract

A magnetoresistance element can have a substrate; a ferromagnetic seed layer consisting of a binary alloy of NiFe; and a first nonmagnetic spacer layer disposed under and directly adjacent to the ferromagnetic seed layer and proximate to the substrate, wherein the first nonmagnetic spacer layer is comprised of Ta or Ru. A method fabricating of fabricating a magnetoresistance element can include depositing a seed layer structure over a semiconductor substrate, wherein the depositing the seed layer structure includes depositing at least a ferromagnetic seed layer over the substrate. The method further can further include depositing a free layer structure over the seed layer structure, wherein the depositing the ferromagnetic seed layer comprises depositing the ferromagnetic seed layer in the presence of a motion along a predetermined direction and in the presence of a predetermined magnetic field having the same predetermined direction.

First claim

What is claimed is:

1. A magnetoresistance element, comprising:
a substrate;
a seed layer structure disposed over the substrate, the seed layer structure comprising:
a ferromagnetic seed layer consisting of a binary alloy of NiFe; and
a first nonmagnetic spacer layer disposed under and directly adjacent to the ferromagnetic seed layer and proximate to the substrate, wherein the first nonmagnetic spacer layer is comprised of Ta or Ru, the magnetoresistance element further comprising:

a free layer structure disposed over the seed layer structure, wherein the ferromagnetic seed layer comprises a crystalline anisotropy, such that the free layer structure is promoted by the seed layer structure to have magnetic domains with magnetic fields oriented in a first direction and to reduce the number of domains with magnetic fields pointing in one or more second different directions.

2. The magnetoresistance element of claim 1 , wherein the seed layer structure further comprises a second nonmagnetic spacer layer disposed over and proximate to or to the ferromagnetic seed layer, wherein the second nonmagnetic spacer layer is comprised of Ta or Ru.

3. The magnetoresistance element of claim 2 , wherein the predetermined magnetic field is between about twenty Oersteds and one hundred fifty Oersteds.

4. The magnetoresistance element of claim 2 , wherein the first and second nonmagnetic spacer layers are each comprised of Ru.

5. The magnetoresistance element of claim 2 , wherein the first and second nonmagnetic spacer layers are each comprised of Ta.

6. The magnetoresistance element of claim 2 , wherein one of the first and second nonmagnetic spacer layers is comprised of Ru and the other one of the first and second nonmagnetic spacer layers is comprised of Ta.

7. The magnetoresistance element of claim 1 , further comprising:
an antiferromagnetic pinning layer disposed over the seed layer structure and under the free layer structure.

8. The magnetoresistance element of claim 7 , wherein the antiferromagnetic pinning layer is comprised of PtMn.

9. The magnetoresistance element of claim 7 , wherein the antiferromagnetic pinning layer is comprised of PtMn, IrMn, or FeMn.

10. The magnetoresistance element of claim 7 , further comprising:
a pinned layer structure disposed over the antiferromagnetic pinning layer and under the free layer structure.

11. The magnetoresistance element of claim 10 , wherein the pinned layer structure comprises:
a first ferromagnetic pinned layer disposed over the antiferromagnetic pinning layer
a third non magnetic spacer layer disposed over the first pinned ferromagnetic layer; and
a second ferromagnetic pinned layer disposed over the third nonmagnetic spacer layer.

12. The magnetoresistance element of claim 11 , wherein the first and second ferromagnetic pinned layers are comprised of CoFe and the third nonmagnetic spacer layer is comprised of Ru.

13. The magnetoresistance element of claim 10 , further comprising:
a fourth nonmagnetic spacer layer disposed between the pinned layer structure and the free layer structure.

14. The magnetoresistance element of claim 13 , wherein the fourth nonmagnetic spacer layer is comprised of Cu, Au, or Ag.

15. The magnetoresistance element of claim 13 , wherein the free layer structure comprises:
a first ferromagnetic free layer disposed over the fourth nonmagnetic spacer layer; and
a second ferromagnetic free layer disposed over the first ferromagnetic free layer.

16. The magnetoresistance element of claim 15 , wherein the first ferromagnetic free layer is comprised of CoFe and the second ferromagnetic free layer is comprised of NiFe.

17. The magnetoresistance element of claim 1 , wherein the free layer structure comprises a plurality of magnetic domains, the plurality of magnetic domains comprising:
a first plurality of magnetic domains with magnetic fields pointing in a first direction; and
a second plurality of magnetic domains with magnetic fields pointing in one or more directions different than the first direction,
wherein a material of the ferromagnetic seed layer results in a selected reduction in a quantity of magnetic domains within the second plurality of magnetic domains in the free layer structure.

18. The magnetoresistance element of claim 1 , wherein the crystalline anisotropy induced by deposition of the ferromagnetic seed layer in the presence of a motion along a predetermined direction and in the presence of a predetermined magnetic field having the same predetermined direction, the crystalline anisotropy resulting in the free layer structure having an enhanced preferential magnetic direction.

19. A method of fabricating a magnetoresistance element, comprising:
depositing a seed layer structure over a semiconductor substrate, wherein the depositing the seed layer structure comprises:
depositing at least a ferromagnetic seed layer over the substrate, wherein the method further comprises:

depositing a free layer structure over the seed layer structure, wherein the depositing the ferromagnetic seed layer comprises depositing the ferromagnetic seed layer in the presence of a motion along a predetermined direction and in the presence of a predetermined magnetic field having the same predetermined direction, resulting in the ferromagnetic seed layer having an enhanced crystalline anisotropy, and resulting in the free layer structure having an enhanced preferential magnetic direction.

20. The method of claim 19 , wherein the depositing the seed layer structure further comprises:
depositing a second nonmagnetic spacer layer over and proximate to or under and proximate to the ferromagnetic seed layer.

21. The method of claim 20 , wherein the ferromagnetic seed layer is comprised of NiFe, NiFeCr, CoFe, CoFeB, or CoFeCr.

22. The method of claim 19 , wherein the ferromagnetic seed layer is comprised of NiFe, NiFeCr, CoFe, CoFeB, or CoFeCr.

23. The method of claim 22 , wherein the predetermined magnetic field is between about twenty Oersteds and one hundred fifty Oersteds.

24. The method of claim 19 , wherein the depositing the seed layer structure further comprises:
depositing a first nonmagnetic spacer layer under and proximate to the ferromagnetic seed layer; and
depositing a second nonmagnetic spacer layer over and proximate to the ferromagnetic seed layer.

25. The method of claim 24 , wherein the ferromagnetic seed layer is comprised of NiFe, NiFeCr, CoFe, CoFeB, or CoFeCr.

26. The method of claim 25 , wherein one of the first and second nonmagnetic spacer layers is comprised of Ru and the other one of the first and second nonmagnetic spacer layers is comprised of Ta, both the first and second nonmagnetic spacer layers are comprised of Ru, or both the first and second nonmagnetic spacer layers are comprised of Ta.

27. The method of claim 19 , further comprising:
depositing an antiferromagnetic pinning layer over the seed layer structure; and
annealing the antiferromagnetic pinning layer using an annealing magnetic field having a primary direction parallel to the predetermined direction of the predetermined magnetic field used in the depositing the ferromagnetic seed layer.

28. The method of claim 27 , wherein the ferromagnetic seed layer is comprised of NiFe, NiFeCr, CoFe, CoFeB, or CoFeCr.

29. The method of claim 28 , wherein the predetermined m

Assignees

• Allegro Microsystems Llc
• Commissariat à l'Energie Atomique et aux Energies Alternatives

Inventors

• Dressler Cyril
• Fermon Claude
• Pannetier-Lecoeur Myriam
• Cyrille Marie-Claire
• Campiglio Paolo

Classifications

• H01F10/3272

  by use of anti-parallel coupled [APC] ferromagnetic layers, e.g. artificial ferrimagnets [AFI], artificial [AAF] or synthetic [SAF] anti-ferromagnets · CPC title

• G01R33/093

  using multilayer structures, e.g. giant magnetoresistance sensors (thin magnetic films H01F10/00) · CPC title

• G11B5/3906

  Details related to the use of magnetic thin film layers or to their effects · CPC title

• G01R33/09 Primary

  Magnetoresistive devices · CPC title

• G01R33/098

  comprising tunnel junctions, e.g. tunnel magnetoresistance sensors · CPC title