MRAM structure with enhanced magnetics using seed engineering

Patent metadata

Field	Value
Publication number	US-11972785-B2
Application number	US-202117526646-A
Country	US
Kind code	B2
Filing date	Nov 15, 2021
Priority date	Nov 15, 2021
Publication date	Apr 30, 2024
Grant date	Apr 30, 2024

Abstract

A memory structure, i.e., magnetoresistive random access memory (MRAM) structure, is provided that includes a seeding area including at least a tunnel barrier seed layer located beneath a chemical templating layer that is wider than the magnetic tunnel junction (MTJ) structure that is located on the chemical templating layer. Redeposited metallic material is located on at least a sidewall of the tunnel barrier seed layer of the seeding area so as to shunt that area of the structure. The memory structure has reduced resistance with minimal tunnel magnetoresistance (TMR) loss penalty.

First claim

What is claimed is:

1. A memory structure comprising:
a bottom electrode embedded in a first interconnect dielectric material layer;
a non-magnetic pedestal structure located on the bottom electrode and a portion of the first interconnect dielectric material layer;
a seeding area having a first width and located on the non-magnetic pedestal structure, wherein the seeding area comprises at least a tunnel barrier seed layer;
a chemical templating layer located on the seeding area;
a magnetic tunnel junction (MTJ) structure having a second width and located on the chemical templating layer, wherein the second width is less than the first width;
a top electrode located on the MTJ structure; and
a layer of non-oxidized metallic residue located on at least a sidewall of the tunnel barrier seed layer and intentionally shunting at least the seeding area.

2. The memory structure of claim 1 , wherein the chemical templating layer comprises an upper portion and a lower portion, wherein the lower portion has a width that is greater than the upper portion and forms an interface with the tunnel barrier seed layer.

3. The memory structure of claim 2 , further comprising a dielectric spacer located on a sidewall of the MTJ structure and the top electrode, and having a bottommost surface that is located on the lower portion of the chemical templating layer.

4. The memory structure of claim 3 , further comprising an encapsulation layer located laterally adjacent to the dielectric spacer, the seeding area and the non-magnetic pedestal structure, and having a bottommost surface located on a surface of the first interconnect dielectric material layer.

5. The memory structure of claim 4 , further comprising a second interconnect dielectric material layer located laterally adjacent to, and above, the encapsulation layer.

6. The memory structure of claim 5 , further comprising an electrically conductive structure embedded in the second interconnect dielectric material layer and contacting the top electrode.

7. The memory structure of claim 6 , wherein the electrically conductive structure has a third width that is greater than at least the second width of the MTJ structure.

8. The memory structure of claim 1 , wherein the layer of non-oxidized metallic residue extends onto a sidewall of the non-magnetic pedestal structure.

9. The memory structure of claim 1 , wherein the layer of non-oxidized metallic residue extends onto a sidewall of a lower portion of the chemical templating layer.

10. The memory structure of claim 9 , wherein the layer of non-oxidized metallic residue extends onto a sidewall of a dielectric spacer that is located laterally adjacent to at least the MTJ structure.

11. The memory structure of claim 1 , wherein the layer of non-oxidized metallic residue extends onto a sidewall of each of the non-magnetic pedestal structure, the lower portion of the chemical templating layer and a dielectric spacer that is located laterally adjacent to at least the MTJ structure.

12. The memory structure of claim 1 , wherein the seeding area further comprises a seed metal layer located beneath the tunnel barrier seed layer.

13. The memory structure of claim 1 , wherein the MTJ structure is a top pinned MTJ structure comprising, from bottom to top, a magnetic free layer, a tunnel barrier layer and a magnetic reference layer.

14. The memory structure of claim 13 , wherein the magnetic free layer comprises an ordered magnetic alloy.

15. The memory structure of claim 14 , wherein the ordered magnetic alloy is a Heusler alloy or a L10 alloy.

16. The memory structure of claim 13 , wherein the magnetic reference layer comprises a single magnetic reference layer.

17. The memory structure of claim 13 , wherein the magnetic reference layer comprises a lower magnetic reference layer, a synthetic anti-ferromagnetic coupling layer and an upper magnetic reference layer.

18. The memory structure of claim 1 , wherein the non-magnetic pedestal structure has a width that is greater than at least the second width of the MTJ structure, and the top electrode has a width that is equal to the second width of the MTJ structure.

19. The memory structure of claim 1 , wherein the layer of non-oxidized metallic residue comprises at least one metal that is present in non-magnetic pedestal structure.

20. The memory structure of claim 1 , wherein the chemical templating layer is a crystallization setting layer for a magnetic free layer of the MTJ structure.

21. The memory structure of claim 1 , wherein the tunnel barrier seed layer has a thickness sufficient to induce magnetic or crystallographic order to a magnetic free layer of the MTJ structure.

Assignees

• IBM

Inventors

• Hashemi Pouya
• Sun Jonathan Zanhong
• Hu Guohan
• Zare Saba

Classifications

• G11C11/161 Primary

  details concerning the memory cell structure, e.g. the layers of the ferromagnetic memory cell · CPC title

• 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

• H10B61/00

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

• H10N50/01 Primary

  Manufacture or treatment · CPC title

• H10N50/10

  Magnetoresistive devices · CPC title