Thin films and methods of forming thin films utilizing ECAE-targets

• US 20040256218A1
• Filed: 05/12/2003
• Published: 12/23/2004
• Est. Priority Date: 05/31/2002
• Status: Abandoned Application

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Glass, Howard L., Alford, Frank, Ferrasse, Stephane
• Application Number:
  US10/436,724
• Publication Number:
  US 20040256218A1
• Time in Patent Office: Days
• US Class Current: 204/192.2
• CPC Class Codes: C23C 14/165 by cathodic sputtering
• CPC Class Codes: C23C 14/3414 Metallurgical or chemical aspects of target preparation, e.g. casting, powder metallurgy
• CPC Class Codes: C23C 14/5853 Oxidation
• CPC Class Codes: Y10T 428/32 Composite [nonstructural laminate] of inorganic material having metal-compound-containing layer and having defined magnetic layer

Abstract

The invention includes methods of forming a barrier layer. Material is ablated from an ECAE target to form a layer having a thickness variance of less than or equal to 1% of 1-sigma across a substrate surface. The invention includes a method of forming a tunnel junction. A thin film is formed between first and second magnetic layers. The thin film, the first magnetic layer, and/or the second magnetic layer are formed by ablating material from an ECAE target to provide improved layer thickness uniformity relative to corresponding layers formed utilizing non-ECAE targets. The invention includes a physical vapor deposition target and a thin film formed using the target. The target contains an alloy of aluminum and at least one alloying element selected from Ga, Zr and In. The resulting film has a thickness variance across the thin film of less than 1.5% of 1-sigma.

Claims

1. A method of forming a barrier layer comprising:

providing an equal channel angular extruded target;

providing a substrate having a surface; and

ablating material from the target to form a layer over the surface, the layer having a thickness that varies less than or equal to about 1% of 1-sigma across the surface.

2. The method of claim 1 wherein the substrate is a 200 mm wafer.

3. The method of claim 1 wherein the substrate is a 300 mm wafer.

4. The method of claim 1 wherein the layer is deposited over a magnetic layer.

5. The method of claim 1 wherein the layer comprises aluminum.

6. The method of claim 1 wherein the layer comprises an aluminum alloy containing at least one alloying element selected from the group consisting of In, Ga and Si.

7. The method of claim 1 wherein the layer comprises Ga.

8. The method of claim 1 wherein the layer comprises In.

9. The method of claim 1 further comprising oxidizing the layer after the ablating to form an oxidized layer.

10. The method of claim 9 wherein the oxidized layer comprises a thickness that deviates less than or equal to about 1% of 1-sigma.

11. The method of claim 9 wherein the oxidized layer has a thickness of less than or equal to about 100 nm.

12. The method of claim 9 wherein the oxidized layer has a thickness of less than or equal to about 10 nm.

13. The method of claim 9 wherein the oxidized layer has a thickness of less than or equal to about 1.0 nm.

14. A method of forming a magnetic tunnel junction comprising:

providing a substrate having a first magnetic layer thereon;

ablating material from an equal channel angular extrusion (ECAE) target to form a thin film over a surface of the first magnetic layer, the thin film having an resistance-area (RA) uniformity of less than or equal to about 1% of 1-sigma standard deviation across the surface; and

depositing a second magnetic layer over the thin film.

15. The method of claim 14 further comprising oxidizing the thin film to form a tunneling barrier oxide layer.

16. The method of claim 14 wherein the first magnetic layer is a fixed ferromagnetic layer.

17. The method of claim 14 wherein the second magnetic layer is a free ferromagnetic layer.

18. The method of claim 14 wherein the ECAE target comprises doped aluminum having at least one dopant element selected from the group consisting of Ag, Au, B, Ba, Be, C, Ca, Cd, Ce, Co, Cr, Cu, Dy, Er, Ey, Fe, Ga, Gd, Ge, Hf, Ho, In, Ir, La, Lu, Mg, Mn, Mo, Nb, Nd, Ni, P, Pb, Pd, Pm, Pr, Pt, Pu, Re, Ru, S, Sb, Sc, Se, Si, Sm, Sn, Sr, Ta, Tb, Te, Ti, Tm, V, W, Y, Yb, Zn, and Zr.

19. The method of claim 14 wherein the thin film comprises an aluminum alloy containing at least one alloying element selected from the group consisting of Ga and In.

20. A method of forming a tunnel junction comprising:

providing a substrate;

forming a first magnetic layer over the substrate;

forming a thin film over the first magnetic layer; and

forming a second magnetic layer over the thin film, at least one layer selected from the first magnetic layer, the thin film and the second magnetic layer being formed by a method comprising ablating material from an equal channel angular extrusion (ECAE) target, the at least one layer having an improved thickness uniformity relative to a corresponding layer formed utilizing a non-ECAE target under otherwise substantially identical conditions.

21. The method of claim 20 wherein the at least one layer has a layer thickness non-uniformity of less than or equal to about 1% of 1-sigma.

22. The method of claim 20 wherein the at least one layer is the first magnetic layer, and wherein the ECAE target comprises at least one of a nickel alloy and a cobalt alloy.

23. The method of claim 20 wherein the at least one layer is the second magnetic layer, and wherein the ECAE target comprises at least one of a nickel alloy and a cobalt alloy.

24. The method of claim 20 wherein the at least one layer is the thin film, and wherein the ECAE target comprises an aluminum alloy.

25. The method of claim 20 further comprising, prior to forming the first magnetic layer, depositing an anti-ferromagnetic layer.

26. The method of claim 25 wherein the anti-ferromagnetic layer comprises an Mn-based material. and wherein the depositing comprises sputtering material from an ECAE target to form the anti-ferromagnetic layer to have a thickness variance of less than about 1% of 1-sigma.

27. The method of claim 20 wherein the at least one layer has a thickness of less than about 10 nm.

28. The method of claim 20 wherein the at least one layer has a thickness of less than about 1.0 nm.

29. The method of claim 20 wherein the at least one layer has an average grain size of less than or equal to about 10 microns.

30. The method of claim 20 wherein the at least one layer has an average grain size of less than or equal to about 5 microns.

31. The method of claim 20 wherein the at least one layer has an average grain size of less than or equal to about 1 micron.

32. The method of claim 20 wherein the forming the thin film comprises depositing a first material having a first thickness and depositing a second material having a second thickness over-the first material.

33. The method of claim 32 further comprising oxidizing at least one of the first material and the second material.

34. The method of claim 32 wherein the first material comprises aluminum and the second material comprises at least one of Cu, Al, Ga, In, Si, and Zr.

35. The method of claim 32 wherein the second material comprises aluminum and the first material comprises at least one of Cu, Al, Ga, In, Si, and Zr.

36. A thin film comprising:

aluminum;

at least one of Ag, Au, B, Ba, Be, C, Ca, Cd, Ce, Co, Cr, Cu, Dy, Er, Ey, Fe, Ga, Gd, Ge, Hf, Ho, In, Ir, La, Lu, Mg, Mn, Mo, Nb, Nd, Ni, P, Pb, Pd, Pm, Pr, Pt, Pu, Re, Ru, S, Sb, Sc, Se, Si, Sm, Sn, Sr, Ta, Tb, Te, Ti, Tm, V, W, Y, Yb, Zn, and Zr; and

a thickness variance across the thin film of less than 1.5% of 1-sigma.

37. The thin film of claim 36 wherein the thickness variance across the film is less than or equal to about 1.0% of 1-sigma.

38. The thin film of claim 36 wherein the thin film has a thickness of less than about 100 nm, wherein the film has an absence of detectable pinholes and an absence of detectable particle defects.

39. The thin film of claim 36 wherein the thin film is formed utilizing an ECAE target and wherein the film comprises at least 50% fewer detectible particles relative to a film produced using a non-ECAE target.

40. The thin film of claim 38 wherein the thickness is less than or equal to about 10 nm.

41. The thin film of claim 38 wherein the thickness is less than or equal to about 1.0 nm.

42. The thin film of claim 36 wherein the thin film comprises a metal oxide.

43. The thin film of claim 42 wherein the metal consists essentially of an aluminum alloy.

44. The thin film of claim 43 wherein the alloy comprises at least one of In, Ga and Cu.

45. The thin film of claim 42 wherein the thin film consists essentially of an oxide of an aluminum alloy.

46. The thin film of claim 42 wherein the thin film consists essentially of aluminum, oxygen and at least one of Ga, In and Cu.

47. A physical vapor deposition target comprising an alloy of aluminum and at least one alloying element selected form the group consisting of Ga, Zr and In, a total amount of the at least one alloying element present in the alloy being greater than 1000 ppm, by weight.

48. The physical vapor deposition target of claim 47 wherein the target consists essentially of the alloy.

49. The physical vapor deposition target of claim 47 wherein the target consists essentially of aluminum and Ga.

50. The physical vapor deposition target of claim 49 wherein the alloy contains from greater than 1000 ppm to about 10% of Ga, by weight.

51. The physical vapor deposition target of claim 47 wherein the target consists essentially of aluminum and In.

52. The physical vapor deposition target of claim 51 wherein the alloy contains from greater than 1000 ppm to about 10% of In, by weight.

53. The physical vapor deposition target of claim 47 wherein the alloy consists essentially of aluminum, Ga and In.

54. The physical vapor deposition target of claim 47 wherein the target consists essentially of aluminum and Zr.

55. A thin film stack comprising:

a first layer having a first thickness;

a second layer having a second thickness disposed over the first layer; and

a third layer having a third thickness disposed over the second layer;

at least one of the first layer, the second layer and the third layer being a sputtered layer formed by a method comprising ablating material from an equal channel angular extruded target to provide a variance across the sputtered layer of less than or equal to 1% of 1-sigma.

56. The thin film stack of claim 55 wherein the first thickness, the second thickness and the third thickness are each less than 100 nm.

57. The thin film stack of claim 55 wherein the first thickness, the second thickness and the third thickness are each less than 20 nm.

58. The thin film stack of claim 55 wherein the first thickness, the second thickness and the third thickness are each less than 10 nm.

59. The thin film stack of claim 55 wherein the second thickness is less than or equal to 1.0 nm.

60. The thin film stack of claim 55 wherein the at least one layer comprises the second layer and wherein the second layer comprises aluminum.

61. The thin film stack of claim 60 wherein each of the first layer and the second layer are ferromagnetic.

62. The thin film stack of claim 55 wherein the at least one layer comprises the second layer and wherein the second layer comprises copper.

63. The thin film stack of claim 62 wherein each of the first layer and the second layer are ferromagnetic.