MAGNETIC MEMORY ELEMENT UTILIZING SPIN TRANSFER SWITCHING

• US 20100109109A1
• Filed: 03/05/2009
• Published: 05/06/2010
• Est. Priority Date: 10/31/2008
• Status: Active Grant

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Yen, Cheng-Tyng, Chen, Wei-Chuan, Wang, Ding-Yeong
• Granted Patent: US 7,829,964 B2
• Time in Patent Office: Days
• US Class Current: 257/421
• CPC Class Codes: G11C 11/161 details concerning the memory cell structure, e.g. the layers of the ferromagnetic memory cell
• CPC Class Codes: H10N 50/10 Magnetoresistive devices

Abstract

A magnetic memory element utilizing spin transfer switching includes a pinned layer, a tunneling barrier layer and a free layer structure. The tunneling barrier layer is disposed on the pinned layer. The free layer structure includes a composite free layer. The composite free layer includes a first free layer, an insert layer and a second free layer. The first free layer is disposed on the tunneling barrier layer and has a first spin polarization factor and a first saturation magnetization. The insert layer is disposed on the first free layer. The second free layer is disposed on the insert layer and has a second spin polarization factor smaller than the first spin polarization factor and a second saturation magnetization smaller than the first saturation magnetization. Magnetization vectors of the first free layer and the second free layer are arranged as parallel-coupled.

Claims

1. A magnetic memory element utilizing spin transfer switching, comprising:

a pinned layer;

a tunneling barrier layer, disposed on the pinned layer; and

a free layer structure, comprising a composite free layer, wherein the composite free layer comprises;

a first free layer, disposed on the tunneling barrier layer and having a first spin polarization factor and a first saturation magnetization;

an insert layer, disposed on the first free layer; and

a second free layer, disposed on the insert layer and having a second spin polarization factor and a second saturation magnetization, wherein

the first spin polarization factor is larger than the second spin polarization factor, the second saturation magnetization is smaller than the first saturation magnetization, and a magnetization vector of the first free layer and a magnetization vector of the second free layer are arranged as parallel-coupled.

2. The magnetic memory element utilizing spin transfer switching as claimed in claim 1, wherein a material of the tunneling barrier layer comprises magnesium oxide (MgO) or aluminum oxide.

3. The magnetic memory element utilizing spin transfer switching as claimed in claim 1, wherein a material of the first free layer comprises a magnetic material.

4. The magnetic memory element utilizing spin transfer switching as claimed in claim 3, wherein the magnetic material is a magnetic alloy of Fe, Ni, Co, and B.

5. The magnetic memory element utilizing spin transfer switching as claimed in claim 1, wherein a material of the insert layer comprises a non-magnetic material.

6. The magnetic memory element utilizing spin transfer switching as claimed in claim 5, wherein the non-magnetic material is Ta, Ru, Mg, Ti, Cu, Cr, Ag, Pt, Pd, Au, TaO_x, RuO_x, MgO or TiO_x.

7. The magnetic memory element utilizing spin transfer switching as claimed in claim 1, wherein a material of the second free layer comprises a magnetic material.

8. The magnetic memory element utilizing spin transfer switching as claimed in claim 7, wherein the magnetic material is a magnetic alloy of Fe, Ni, Co and B.

9. The magnetic memory element utilizing spin transfer switching as claimed in claim 1, wherein a thickness of the insert layer is a thickness sufficient to render the magnetization vector of the first free layer and the magnetization vector of the second free layer arranged as parallel-coupled.

10. The magnetic memory element utilizing spin transfer switching as claimed in claim 1, wherein a thickness of the insert layer is 1-6 angstroms or 12-18 angstroms.

11. The magnetic memory element utilizing spin transfer switching as claimed in claim 1, further comprising a pinning layer, wherein the pinned layer is disposed on the pinning layer.

12. The magnetic memory element utilizing spin transfer switching as claimed in claim 11, wherein a material of the pinning layer comprises an anti-ferromagnetic material.

13. The magnetic memory element utilizing spin transfer switching as claimed in claim 1, further comprising a capping layer disposed on the composite free layer.

14. The magnetic memory element-utilizing spin transfer switching as claimed in claim 13, wherein a material of the capping layer is Ta, Ti, Ru, AlO_x or MgO.

15. The magnetic memory element utilizing spin transfer switching as claimed in claim 1, wherein the free layer structure comprises a synthetic anti-ferromagnetic free layer.

16. The magnetic memory element utilizing spin transfer switching as claimed in claim 15, wherein when the free layer structure is the synthetic anti-ferromagnetic free layer, the free layer structure further comprises:

a first spacer layer, disposed on the composite free layer; and

a third free layer, disposed on the first spacer layer.

17. The magnetic memory element utilizing spin transfer switching as claimed in claim 16, wherein a material of the first spacer layer is Ru, Cr or Cu.

18. The magnetic memory element utilizing spin transfer switching as claimed in claim 16, wherein a material of the third free layer comprises a magnetic material.

19. The magnetic memory element utilizing spin transfer switching as claimed in claim 16, wherein the third free layer is an identical layer as the composite free layer.

20. The magnetic memory element utilizing spin transfer switching as claimed in claim 1, further comprising a stabilized layer disposed on the free layer structure.

21. The magnetic memory element utilizing spin transfer switching as claimed in claim 20, wherein the stabilized layer comprises an anti-ferromagnetic layer.

22. The magnetic memory element utilizing spin transfer switching as claimed in claim 21, wherein the anti-ferromagnetic layer comprises PtMn, IrMn, FeMn.

23. The magnetic memory element utilizing spin transfer switching as claimed in claim 21, wherein a thickness of the anti-ferromagnetic layer is within a range of 10 angstroms to 50 angstroms.

24. The magnetic memory element utilizing spin transfer switching as claimed in claim 21, further comprising a second spacer layer disposed between the free layer structure and the anti-ferromagnetic layer.

25. The magnetic memory element utilizing spin transfer switching as claimed in claim 24, wherein a thickness of the anti-ferromagnetic layer is greater than 50 angstroms.

26. The magnetic memory element utilizing spin transfer switching as claimed in claim 24, wherein a material of the second spacer layer comprises a metal with a spin diffusion length greater than 100 angstroms.

27. The magnetic memory element utilizing spin transfer switching as claimed in claim 26, wherein the metal is Ru, Ta, Ti, Cu, Au, Ag, Al, Pt or Pd.

28. A magnetic memory element utilizing spin transfer switching, comprising:

a pinned layer;

a tunneling barrier layer, disposed on the pinned layer;

a free layer, disposed on the tunneling barrier layer; and

a stabilized layer, disposed on the free layer and having a thickness within a range of 10 angstroms to 50 angstroms.

29. The magnetic memory element utilizing spin transfer switching as claimed in claim 28, wherein a material of the tunneling barrier layer comprises magnesium oxide (MgO) or aluminum oxide.

30. The magnetic memory element utilizing spin transfer switching as claimed in claim 28, wherein a material of the free layer comprises a magnetic material.

31. The magnetic memory element utilizing spin transfer switching as claimed in claim 28, wherein a material of the stabilized layer comprises an anti-ferromagnetic material.

32. The magnetic memory element utilizing spin transfer switching as claimed in claim 28, further comprising a pinning layer, wherein the pinned layer is disposed on the pinning layer.

33. The magnetic memory element utilizing spin transfer switching as claimed in claim 32, wherein a material of the pinning layer comprises an anti-ferromagnetic material.

34. The magnetic memory element utilizing spin transfer switching as claimed in claim 28, further comprising a capping layer disposed on the stabilized layer.

35. The magnetic memory element utilizing spin transfer switching as claimed in claim 34, wherein a material of the capping layer is Ta, Ti, Ru, AlO_x or MgO.

36. A magnetic memory element utilizing spin transfer switching, comprising:

a pinned layer;

a tunneling barrier layer, disposed on the pinned layer;

a free layer, disposed on the tunneling barrier layer;

a spacer layer, disposed on the free layer, wherein a material of the spacer layer comprises a metal with a spin diffusion length greater than 100 angstroms; and

a stabilized layer having a thickness greater than 50 angstroms, disposed on the spacer layer.

37. The magnetic memory element utilizing spin transfer switching as claimed in claim 36, wherein a material of the tunneling barrier layer comprises magnesium oxide (MgO) or aluminum oxide.

38. The magnetic memory element utilizing spin transfer switching as claimed in claim 36, wherein a material of the free layer comprises a magnetic material.

39. The magnetic memory element utilizing spin transfer switching as claimed in claim 36, wherein the metal is Ru, Ta, Ti, Cu, Au, Ag, Al, Pt or Pd.

40. The magnetic memory element utilizing spin transfer switching as claimed in claim 36, wherein a material of the stabilized layer comprises an anti-ferromagnetic material.

41. The magnetic memory element utilizing spin transfer switching as claimed in claim 36, further comprising a pinning layer, wherein the pinned layer is disposed on the pinning layer.

42. The magnetic memory element utilizing spin transfer switching as claimed in claim 41, wherein a material of the pinning layer comprises an anti-ferromagnetic material.

43. The magnetic memory element utilizing spin transfer switching as claimed in claim 36, further comprising a capping layer disposed on the stabilized layer.

44. The magnetic memory element utilizing spin transfer switching as claimed in claim 43, wherein a material of the capping layer is Ta, Ti, Ru, AlO_x or MgO.