METHOD AND SYSTEM FOR PROVIDING FIELD BIASED MAGNETIC MEMORY DEVICES

• US 20080273380A1
• Filed: 03/27/2007
• Published: 11/06/2008
• Est. Priority Date: 03/27/2007
• Status: Active Grant

• Current Assignee: Renesas Electronics Corporation, Samsung Semiconductor Incorporated (Samsung Electronics Co. Ltd.)
• Original Assignee: Grandis, Inc. (Samsung Electronics Co. Ltd.)
• Inventors: Huai, Yiming, Diao, Zhitao, Wang, Lien-Chang
• Granted Patent: US 7,738,287 B2
• Time in Patent Office: Days
• US Class Current: 365/171
• CPC Class Codes: G11C 11/16 using elements in which the storage effect is based on magnetic spin effect
• CPC Class Codes: Y10T 29/49002 Electrical device making

Abstract

A method and system for providing a magnetic memory is disclosed. The method and system include providing a plurality of magnetic storage cells in an array, a plurality of bit lines, and at least one bias structure. Each of the plurality of magnetic storage cells includes at least one magnetic element having an easy axis and being programmable by at least one write current driven through the magnetic element. The plurality of bit lines corresponds to the plurality of magnetic storage cells. The at least one bias structure is magnetically coupled with the at least one magnetic element in each of the plurality of magnetic storage cells. The at least one bias structure provides a bias field in a direction greater than zero degrees and less than one hundred eighty degrees from the easy axis.

Claims

1. A magnetic memory comprising:

a plurality of magnetic storage cells in an array, each of the plurality of magnetic storage cells including at least one magnetic element, the at least one magnetic element having an easy axis and being programmable by at least one write current driven through the magnetic element;

a plurality of bit lines corresponding to the plurality of magnetic storage cells; and

at least one bias structure magnetically coupled with the at least one magnetic element in each of the plurality of magnetic storage cells, the at least one bias structure providing a bias field in a direction greater than zero degrees and less than one hundred eighty degrees from the easy axis.

2. The magnetic memory of claim 1 wherein the angle is at least eighty degrees and not more than one hundred degrees.

3. The magnetic memory of claim 2 wherein the angle is substantially ninety degrees.

4. The magnetic memory of claim 1 wherein the bias structure further includes:

at least one magnetically soft layer magnetostatically coupled to the at least one magnetic element.

5. The magnetic memory of claim 4 wherein the at least one magnetically soft layer is adjacent to each of the plurality of bit lines.

6. The magnetic memory of claim 5 wherein the plurality of bit lines resides between the at least one magnetic element and the at least one magnetically soft layer.

7. The magnetic memory of claim 5 wherein each of the plurality of bit lines includes at least one of Cu, Au, Al, Ag, CuAg, AlCu, Ta, Cr, NiCr, NiFeCr, Ru, and Rh.

8. The magnetic memory of claim 5 wherein the magnetically soft layer includes at least one of Co, Ni, and Fe and has a coercivity of not more than one hundred Oersteds.

9. The magnetic memory of claim 5 wherein the magnetically soft layer includes a material, the free layer also including the material.

10. The magnetic memory of claim 9 wherein the at least one magnetic element includes at least one free layer having a free layer thickness, the magnetically soft layer having a thickness greater than the free layer thickness.

11. The magnetic memory of claim 10 wherein the thickness of the magnetically soft layer is not more than few hundred nanometers.

12. The magnetic memory of claim 5 wherein each of the plurality of bit lines have a bit line direction.

13. The magnetic memory of claim 12 wherein the easy axis is substantially perpendicular to the bit line direction.

14. The magnetic memory of claim 5 wherein the bias structure further includes a stabilizing structure coupled with the magnetically soft layer.

15. The magnetic memory of claim 14 wherein the stabilizing structure further includes an antiferromagnetic material adjacent to the magnetically soft layer.

16. The magnetic memory of claim 15 wherein the antiferromagnetic material includes at least one of PtMn, NiMn, IrMn, OsMn, PdPtMn, CrPtMn, NiO, CoO, and CoNiO.

17. The magnetic memory of claim 14 wherein the stabilizing structure further includes a permanent magnetic material.

18. The magnetic memory of claim 16 wherein the permanent magnetic material includes at least one of Co, CoCr, FeCr, CoFeCr, CoCrPt, CoPt, CoCrB, CoPtB, CoP and CoNiFe.

19. The magnetic memory of claim 1 wherein the bias structure further includes a magnetic shield substantially surrounding a portion of the at least one magnetic element.

20. The magnetic memory of claim 19 wherein the bias structure further includes an insulator residing between the portion of the at least one magnetic element and the magnetic shield.

21. The magnetic memory of claim 20 wherein the at least one magnetic element includes at least one free layer, the portion of the at least one magnetic element including the at least one free layer.

22. The magnetic memory of claim 20 wherein the magnetic shield includes a material, the free layer also including the material.

23. The magnetic memory of claim 20 wherein the magnetic shield further includes at least one of CoFe, NiFe, CoFeNi, CoFeB, CoZrB, CoHfB, and FeN.

24. The magnetic memory of claim 20 wherein the bias structure further includes a stabilizing structure coupled with the magnetic shield.

25. The magnetic memory of claim 24 wherein the stabilizing structure further includes an antiferromagnetic material adjacent to the magnetic shield.

26. The magnetic memory of claim 25 wherein the antiferromagnetic material includes at least one of PtMn, NiMn, IrMn, OsMn, PdPtMn, CrPtMn, NiO, CoO, and CoNiO.

27. The magnetic memory of claim 24 wherein the stabilizing structure further includes a permanent magnetic material.

28. The magnetic memory of claim 27 wherein the permanent magnetic material includes at least one of Co, CoCr, FeCr, CoFeCr, CoCrPt, CoPt, CoCrB, CoPtB, CoP and CoNiFe.

29. The magnetic memory of claim 20 wherein each of the plurality of bit lines have a bit line direction.

30. The magnetic memory of claim 29 wherein the easy axis is substantially parallel to the bit line direction.

31. The magnetic memory of claim 29 further comprising:

a plurality of lines coupled with the magnetic storage cells, the plurality of lines and the plurality of bit lines being configured to drive at least one write current and at least one read current through the at least one magnetic element.

32. A method for providing a magnetic memory comprising:

providing a plurality of magnetic storage cells in an array, each of the plurality of magnetic storage cells including at least one magnetic element, the at least one magnetic element having an easy axis and being programmable by at least one write current driven through the magnetic element;

providing a plurality of bit lines corresponding to the plurality of magnetic storage cells; and

providing at least one bias structure magnetically coupled with the at least one magnetic element in each of the plurality of magnetic storage cells, the at least one bias structure providing a bias field in a direction greater than zero degrees and less than one hundred eighty degrees from the easy axis.