Memory devices comprising magnetic tracks individually comprising a plurality of magnetic domains having domain walls and methods of forming a memory device comprising magnetic tracks individually comprising a plurality of magnetic domains having domain walls

• US 9,048,410 B2
• Filed: 05/31/2013
• Issued: 06/02/2015
• Est. Priority Date: 05/31/2013
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Baldi, Livio, Mariani, Marcello
• Primary Examiner(s): WILCZEWSKI, MARY A
• Application Number:
  US13/906,857
• Publication Number:
  US 20140353781A1
• Time in Patent Office: 732 Days
• Field of Search: 438/3, 438/692, 257/421
• US Class Current: 1/1
• CPC Class Codes: G11B 5/4946 for formation or displacement of magnetic domains, e.g. walls, bubbles
• CPC Class Codes: G11C 11/14 using thin-film elements
• CPC Class Codes: G11C 11/161 details concerning the memory cell structure, e.g. the layers of the ferromagnetic memory cell
• CPC Class Codes: G11C 11/1675 Writing or programming circuits or methods
• CPC Class Codes: G11C 19/0808 using magnetic domain propagation
• CPC Class Codes: H10N 50/01 Manufacture or treatment
• CPC Class Codes: H10N 50/80 Constructional details

Abstract

A method of forming a memory device having magnetic tracks individually comprising a plurality of magnetic domains having domain walls, includes forming an elevationally outer substrate material of uniform chemical composition. The uniform composition material is partially etched into to form alternating regions of elevational depressions and elevational protrusions in the uniform composition material. A plurality of magnetic tracks is formed over and which angle relative to the alternating regions. Interfaces of immediately adjacent of the regions individually form a domain wall pinning site in individual of the magnetic tracks. Other methods, including memory devices independent of method, are disclosed.

Claims

1. A method of forming a memory device comprising magnetic tracks individually comprising a plurality of magnetic domains having domain walls, comprising:

forming alternating elevationally outer regions of two different composition materials;

removing one of the two different composition materials inwardly to an elevationally outermost location of the one material that is deeper than an elevationally outermost location of the other of the two different composition materials at the end of said removing to form alternating regions of elevational depressions and elevational protrusions; and

forming a plurality of magnetic tracks over and which angle relative to the alternating regions, interfaces of immediately adjacent of the regions individually comprising a domain wall pinning site in individual of the magnetic tracks.

2. The method of claim 1 wherein the removing removes some of both of the two different composition materials.

3. The method of claim 1 wherein the removing comprises polishing.

4. The method of claim 3 wherein the removing comprises chemical mechanical polishing.

5. The method of claim 3 wherein the polishing removes some of both of the two different composition materials, the one being over-polished relative the other.

6. The method of claim 1 wherein the removing comprises chemical etching in the absence of any mechanical polishing component.

7. The method of claim 6 wherein the chemical etching does not measurably etch the other of the two different composition materials.

8. The method of claim 6 wherein the chemical etching also etches the other of the two different composition materials.

9. The method of claim 1 wherein the two materials may be characterized by chemically different compositions.

10. The method of claim 9 wherein the two chemically different compositions respectively comprise silicon dioxide and silicon nitride.

11. The method of claim 9 wherein the one is a first composition and the other is a second composition, the forming of the alternating regions comprises:

depositing one of the first composition or the second composition over underlying substrate material;

etching through said one of the first or second compositions to the underlying substrate material; and

forming said other of the first or second compositions over the underlying substrate material between said one of the first or second compositions.

12. The method of claim 9 wherein the one is a first composition and the other is a second composition, the forming of the alternating regions comprises:

depositing one of the first composition or the second composition over underlying substrate material;

etching through said one of the first or second compositions into the underlying material to form trenches in the underlying material and said one of the first and second compositions; and

over-filling the trenches with the other of the first and second compositions.

13. The method of claim 1 wherein immediately adjacent of the regions are of the same chemical composition and of different physical compositions relative one another.

14. A method of forming a memory device comprising magnetic tracks individually comprising a plurality of magnetic domains having domain walls, comprising:

forming an elevationally outer substrate material elevationally over underlying material;

etching through the elevationally outer substrate material into the underlying material to form trenches in the underlying material and the outer substrate material;

over-filling the trenches with material of different composition from that of the outer substrate material;

removing the material of different composition to expose the outer substrate material;

removing one of the material of different composition or the outer substrate material inwardly to form alternating regions of elevational depressions and elevational protrusions; and

forming a plurality of magnetic tracks over and which angle relative to the alternating regions, interfaces of immediately adjacent of the regions individually comprising a domain wall pinning site in individual of the magnetic tracks.

15. The method of claim 14 wherein the removing to form the alternating regions is of the material of different composition.

16. The method of claim 14 wherein the removing to form the alternating regions is of the outer substrate material.