Magnetic memory cells and methods of formation

Patent metadata

Field	Value
Publication number	US-9548444-B2
Application number	US-201514685236-A
Country	US
Kind code	B2
Filing date	Apr 13, 2015
Priority date	Mar 22, 2012
Publication date	Jan 17, 2017
Grant date	Jan 17, 2017

Abstract

Memory cells including cell cores having free regions are disclosed. The free regions exhibit a strain that affects a magnetization orientation within the cell core. A stressor structure may exert a stress upon at least a portion of the cell core to effect the strain state of the free region. Also disclosed are semiconductor device structures and systems including such memory cells as well as methods for forming such memory cells.

First claim

What is claimed is:

1. A magnetic memory cell, comprising:
a cell core comprising:
a free region exhibiting a vertical magnetic orientation;
a pinned region exhibiting a vertical magnetic orientation; and
a nonmagnetic region between the free region and the pinned region;

a stressor structure external to the cell core and directly, laterally about at least a portion of the cell core, the stressor structure applying a stress to at least the portion of the cell core to effect a strain exhibited by the free region, the strain effecting the vertical magnetic orientation exhibited by the free region, the stressor structure defining a uniform lateral thickness along a height of the stressor structure;
an insulative material directly, laterally about the stressor structure;
a conductive material above the cell core and the stressor structure; and
another conductive material beneath the cell core and the stressor structure.

2. The magnetic memory cell of claim 1 , wherein the stressor structure comprises at least one of silicon oxide (SiO) and silicon nitride (Si 3 N 4 ).

3. The magnetic memory cell of claim 1 , wherein the stressor structure defines a width less than or equal to a width defined by at least one of the conductive material and the another conductive material.

4. The magnetic memory cell of claim 1 , further comprising another stressor structure physically isolated from the cell core.

5. The magnetic memory cell of claim 1 , wherein the stressor structure comprises a first stressor material and a second stressor material.

6. The magnetic memory cell of claim 5 , wherein the first stressor material is disposed between the cell core and the second stressor material.

7. The magnetic memory cell of claim 1 , further comprising another stressor structure vertically adjacent the cell core.

8. A method of forming a magnetic memory cell, the method comprising:
forming a cell core comprising at least one magnetic region over a substrate;
forming a stressor structure proximate to and isolated from the cell core, isolated from a conductive material directly above the cell core, and isolated from another conductive material directly beneath the cell core; and
cooling the stressor structure and the cell core to contract the stressor structure and apply a stress upon at least the at least one magnetic region of the cell core, the stress effecting a strain in the at least one magnetic region that effects a vertical magnetic orientation exhibited by the at least one magnetic region.

9. The method of claim 8 , wherein forming a stressor structure comprises forming a spin-on glass material.

10. The method of claim 8 , wherein forming a stressor structure proximate to and isolated from the cell core comprises forming the stressor structure laterally surrounding at least a portion of the cell core.

11. The method of claim 10 , further comprising forming another stressor structure proximate to and isolated from at least the portion of the cell core.

12. The method of claim 8 , further comprising:
forming the conductive material above the cell core and the stressor structure; and
forming the another conductive material beneath the cell core and the stressor structure.

13. A magnetic memory cell, comprising:
a stressor structure comprising silicon oxide;
a cell core structure free of internal stressor material and extending through the stressor structure, the cell core structure comprising a magnetic tunnel junction comprising a magnetic region exhibiting a strain effected by a stress applied by the stressor structure, the strain effecting a vertical magnetic orientation exhibited by the magnetic region;
an insulative material laterally adjacent the stressor structure;
a conductive material above the stressor structure; and
another conductive material beneath the stressor structure.

14. The magnetic memory cell of claim 13 , wherein the stressor structure extends directly between the conductive material and the another conductive material.

15. The magnetic memory cell of claim 13 , wherein the insulative material laterally surrounds the stressor structure.

16. The magnetic memory cell of claim 13 , wherein the insulative material is further vertically about the stressor structure.

17. The magnetic memory cell of claim 13 , wherein the vertical magnetic orientation exhibited by the magnetic region is a switchable vertical magnetic orientation.

18. The magnetic memory cell of claim 13 , wherein the stressor structure contacts the cell core structure.

19. The magnetic memory cell of claim 13 , wherein the stressor structure extends laterally beyond at least one of the conductive material and the another conductive material.

20. The magnetic memory cell of claim 13 , wherein the stressor structure extends at least a height of the magnetic tunnel junction.

Assignees

• Micron Technology Inc

Inventors

• Sandhu Gurtej S
• Kinney Wayne I

Classifications

• G11C11/15

  using multiple magnetic layers (G11C11/155 takes precedence) · CPC title

• G11C11/161 Primary

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

• H01F10/3286 Primary

  Spin-exchange coupled multilayers having at least one layer with perpendicular magnetic anisotropy · CPC title

• H01F10/1936

  Half-metallic, e.g. epitaxial CrO2 or NiMnSb films · CPC title

• H01F10/329

  Spin-exchange coupled multilayers wherein the magnetisation of the free layer is switched by a spin-polarised current, e.g. spin torque effect · CPC title