MRAM structure using sacrificial layer for anti-ferromagnet and method of manufacture

• US 20070278602A1
• Filed: 06/06/2006
• Published: 12/06/2007
• Est. Priority Date: 06/06/2006
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Altis Semiconductor (Altis International), Infineon Technologies AG
• Inventors: Raberg, Wolfgang, Klostermann, Ulrich
• Granted Patent: US 7,782,577 B2
• Time in Patent Office: Days
• US Class Current: 257/421
• CPC Class Codes: H10N 50/01 Manufacture or treatment
• CPC Class Codes: H10N 50/10 Magnetoresistive devices

Abstract

A magnetic random access memory structure comprising an anti-ferromagnetic layer structure, a crystalline ferromagnetic structure physically coupled to the anti-ferromagnetic layer structure and a ferromagnetic free layer structure physically coupled to the crystalline ferromagnetic structure.

Claims

1. A magnetic random access memory structure, comprising:

an anti-ferromagnetic layer structure;

a crystalline ferromagnetic structure physically coupled to the anti-ferromagnetic layer structure; and

a ferromagnetic free layer structure physically coupled to the crystalline ferromagnetic structure.

2. The magnetic random access memory structure of claim 1, further comprising:

a non-magnetic barrier layer physically coupled to the ferromagnetic free layer structure; and

a magnetic reference layer structure physically coupled to the non-magnetic barrier layer.

3. The magnetic random access memory structure of claim 1, wherein the ferromagnetic free layer structure and the crystalline ferromagnetic structure are substantially matched to one another with regard to their crystal structure.

4. The magnetic random access memory structure of claim 1, wherein the ferromagnetic free layer structure comprises an amorphous layer structure.

5. The magnetic random access memory structure of claim 1, wherein the ferromagnetic free layer structure comprises a crystalline or polycrystalline layer structure.

6. The magnetic random access memory structure of claim 1, wherein the ferromagnetic free layer structure has a thickness in the range between 10 Angstrom to 200 Angstrom.

7. The magnetic random access memory structure of claim 1, wherein the ferromagnetic free layer structure is made of a material comprising elements selected from the group consisting of cobalt, iron, boron, nickel.

8. The magnetic random access memory structure of claim 7, wherein the ferromagnetic free layer structure comprises cobalt iron boron or nickel iron boron.

9. The magnetic random access memory structure of claim 1, wherein the crystalline ferromagnetic structure has a thickness in the range between 5 Angstrom to 100 Angstrom.

10. The magnetic random access memory structure of claim 1, wherein the crystalline ferromagnetic structure comprises nickel iron.

11. The magnetic random access memory structure of claim 1, wherein the anti-ferromagnetic layer structure has a thickness in the range between 20 Angstrom to 150 Angstrom.

12. The magnetic random access memory structure of claim 1, wherein the anti-ferromagnetic layer structure comprises a material comprising elements selected from the group consisting of iridium, manganese, iron and nickel.

13. The magnetic random access memory structure of claim 12, wherein the anti-ferromagnetic layer structure comprises iridium manganese, nickel manganese, iron manganese or nickel iron manganese.

14. A magnetic random access memory structure, comprising:

an anti-ferromagnetic layer structure;

a crystalline ferromagnetic structure physically coupled to the anti-ferromagnetic layer structure;

a ferromagnetic free layer structure physically coupled to the crystalline ferromagnetic structure;

a non-magnetic barrier layer physically coupled to the ferromagnetic free layer structure; and

a magnetic reference layer structure physically coupled to the non-magnetic barrier layer, wherein the ferromagnetic free layer structure and the crystalline ferromagnetic structure are substantially matched to one another with regard to their crystal structure.

15. A method for manufacturing a magnetic random access memory structure, comprising

providing an anti-ferromagnetic layer structure;

providing a crystalline ferromagnetic structure physically coupled to the anti-ferromagnetic layer structure; and

providing a ferromagnetic free layer structure physically coupled to the crystalline ferromagnetic structure.

16. The method of claim 15, further comprising annealing the anti-ferromagnetic layer structure and the crystalline ferromagnetic structure together such that the material of the crystalline ferromagnetic structure reacts with material of the anti-ferromagnetic layer structure.

17. The method of claim 16, wherein the anti-ferromagnetic layer structure and the crystalline ferromagnetic structure are annealed together at a temperature between 150°

C. and 350°

C.

18. The method of claim 17, wherein the anti-ferromagnetic layer structure and the crystalline ferromagnetic structure are annealed together at a temperature between 230°

C. and 280°

C.

19. The method of claim 16, wherein the anti-ferromagnetic layer structure and the crystalline ferromagnetic structure are annealed together for longer than one hour.