Spinodally Patterned Nanostructures

• US 20080268288A1
• Filed: 05/10/2006
• Published: 10/30/2008
• Est. Priority Date: 05/10/2005
• Status: Active Grant

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Jin, Sungho
• Granted Patent: US 7,820,064 B2
• Time in Patent Office: Days
• US Class Current: 428/800
• CPC Class Codes: B81C 1/00031 Regular or irregular arrays of nanoscale structures, e.g. etch mask layer photomechanical, e.g. photolithographic, production of textured or patterned surfaces G03F7/00; lithographic processes for making patterned surfaces using printing and stamping G03F7/0002
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 25/00 Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: C23C 14/04 Coating on selected surface areas, e.g. using masks
• CPC Class Codes: C23C 26/00 Coating not provided for in groups C23C2/00 - C23C24/00
• CPC Class Codes: G03F 1/20 Masks or mask blanks for imaging by charged particle beam [CPB] radiation, e.g. by electron beam; Preparation thereof
• CPC Class Codes: G03F 7/0002 Lithographic processes using patterning methods other than those involving the exposure to radiation, e.g. by stamping
• CPC Class Codes: G11B 5/855 Coating only part of a support with a magnetic layer
• CPC Class Codes: H01F 1/009 bidimensional, e.g. nanoscale period nanomagnet arrays H01F10/007 takes precedence
• CPC Class Codes: H01F 41/34 in patterns, e.g. by lithography
• CPC Class Codes: H10B 69/00 Erasable-and-programmable ROM [EPROM] devices not provided for in groups H10B41/00 - H10B63/00, e.g. ultraviolet erasable-and-programmable ROM [UVEPROM] devices
• CPC Class Codes: Y10T 428/24802 Discontinuous or differential coating, impregnation or bond [e.g., artwork, printing, retouched photograph, etc.]

Abstract

Devices based on spinodally decomposed periodic structures and their fabrication techniques.

Claims

1. A method, comprising:

forming a layer to be patterned over a substrate;

forming a spinodal alloy layer on the layer to be patterned, wherein the spinodal alloy layer comprises a plurality of alloy elements and, when the spinodal alloy layer is at a temperature within a spinodal decomposition temperature range for the two phases formed by the alloy elements, decomposes into two phases that are spatially separated and spatially interleaved in a spinodally decomposed periodic structure;

controlling a temperature of the spinodal alloy layer to be within the spinodal decomposition temperature range to form the spinodally decomposed periodic structure;

patterning the spinodal alloy layer in the spinodally decomposed periodic structure to remove one of the two phases and hence to transform the spinodal alloy layer into a patterned mask which exposes the layer to be patterned according to the spinodally decomposed periodic structure; and

patterning the layer to be patterned through the patterned mask in the spinodal alloy layer to form a patterned layer.

2. The method as in claim 1, wherein:

the controlling of the temperature of the spinodal alloy layer to be within the spinodal decomposition temperature range comprises;

heating the spinodal alloy layer from a lower temperature into the spinodal decomposition temperature range.

3. The method as in claim 1, wherein:

the controlling of the temperature of the spinodal alloy layer to be within the spinodal decomposition temperature range comprises;

cooling the spinodal alloy layer from a higher temperature into the spinodal decomposition temperature range.

4. The method as in claim 1, further comprising:

removing the patterned mask in the spinodal alloy layer; and

subsequently forming a third structure within an opening or a ridge of the patterned layer.

5. The method as in claim 4, wherein:

the third structure is a quantum dot structure operable to emit light under optical excitation.

6. The method as in claim 5, wherein:

the quantum dot structure comprises one of Si, CdSe, CdS, CdTe, ZnS, InP, InAs, InGaAs, GaAs, and GaN.

7. The method as in claim 4, wherein:

the third structure is a surface plasmon resonance structure made of an electrically conductive metallic material.

8. The method as in claim 7, wherein:

the third structure comprises one of Au, Ag, Pt, Ni, and Co.

9. The method as in claim 4, wherein:

the third structure is a magnetic recording structure.

10. The method as in claim 4, wherein:

the third structure is a hetero expitaxially grown structure.

11. The method as in claim 4, wherein:

the third structure is a preferential nucleation grown structure.

12. The method as in claim 1, wherein:

the layer to be patterned is made of a hard magnetic material.

13. The method as in claim 12, wherein:

the hard magnetic material comprises FePt, CoPt ,Sm—

Co, CoCrPt, Nd—

Fe—

B, [CoPd]_n alternating multilayer, or [FePt]_n alternating multilayer.

14. The method as in claim 12, further comprising:

prior to forming the layer to be patterned, forming a soft magnetic underlayer over the substrate on which the layer to be patterned is subsequently formed and patterned.

15. The method as in claim 14, wherein:

the soft magnetic underlayer comprises a magnetic material exhibiting a magnetic coercive force less than 10 oersteds.

16. The method as in claim 14, wherein:

the soft magnetic underlayer comprises an Ni—

Fe permalloy, Fe—

Co base alloy, Fe—

Co—

B alloy, and Fe—

Ta—

N alloy.

17. The method as in claim 1, wherein:

the layer to be patterned includes a soft magnetic underlayer and a hard magnetic layer on top of the soft magnetic underlayer.

18. The method as in claim 17, further comprising:

applying an annealing treatment to the soft magnetic underlayer and the hard magnetic layer.

19. The method as in claim 1, wherein:

the patterned layer is an array of isolated islands on the substrate, and the method further comprising;

removing the patterned mask in the spinodal alloy layer; and

subsequently forming a coating layer made of a single metal element or an alloy to cover the isolated islands and areas of the substrate exposed between the isolated islands; and

applying an annealing treatment to the coating layer to cause the coating layer to retract from the areas of the substrate between the isolated islands so that the isolated islands are separately covered by the coating layer leaving a portion of each area of the substrate between two adjacent isolated islands free of the coating layer.

20. The method as in claim 19, further comprising:

applying an additional appealing treatment to cause alloying between the coating layer and each isolated island covered by the coating layer.

21. The method as in claim 19, wherein:

the layer to be patterned is made of a soft magnetic material; and

the coating layer is made of a hard magnetic material.

22. The method as in claim 1, wherein:

the layer to be patterned is made of a catalyst for nanowires or nanotubes; and

the patterned layer is an array of islands of the catalyst; and

the method further comprising;

performing a chemical vapor deposition process to grow nanowires or nanotubes at sites of the islands.

23. The method as in claim 22, wherein the layer to be patterned is made of Ni, Fe or Co as a catalyst for growing carbon nanotubes.

24. The method as in claim 22, wherein the layer to be patterned is made of Au as a catalyst for growing nanotubes.

47. A device fabricated according to claim 1.

25. A method, comprising:

forming a spinodal alloy layer on a substrate, wherein the spinodal alloy layer comprises a plurality of alloy elements and, when the spinodal alloy layer is at a temperature within a spinodal decomposition temperature range for the two phases formed by the alloy elements, decomposes into two phases that are spatially separated and spatially interleaved in a spinodally decomposed periodic structure;

controlling a temperature of the spinodal alloy layer to be within the spinodal decomposition temperature range to form the spinodally decomposed periodic structure; and

etching the substrate through the spinodal alloy layer in the spinodally decomposed periodic structure to pattern the substrate.

26. The method as in claim 25, further comprising:

removing the spinodal alloy layer from the patterned substrate; and

forming a layer on the patterned substrate.

27. The method as in claim 25, wherein:

the layer is a magnetic layer.

28. The method as in claim 25, wherein:

the layer comprises a quantum dot structure operable to emit light under optical excitation.

29. A method, comprising:

forming a spinodal alloy layer on a substrate, wherein the spinodal alloy layer comprises a plurality of alloy elements and, when the spinodal alloy layer is at a temperature within a spinodal decomposition temperature range for the two phases formed by the alloy elements, decomposes into two phases that are spatially separated and spatially interleaved in a spinodally decomposed periodic structure;

controlling a temperature of the spinodal alloy layer to be within the spinodal decomposition temperature range to form the spinodally decomposed periodic structure; and

patterning the spinodal alloy layer in the spinodally decomposed periodic structure to remove one of the two phases and hence to transform the spinodal alloy layer into a patterned spinodal alloy layer made of a remaining phase of the two phases in the spinodal alloy layer.

30. The method as in claim 29, wherein:

the patterned spinodal alloy layer is an array of islands; and

the remaining phase is a catalyst for nanowires or nanotubes; and

the method further comprising;

performing a chemical vapor deposition process to grow nanowires or nanotubes at sites of the islands.

31. The method as in claim 30, wherein:

the spinodal alloy layer is made of a Cu—

Ni—

Fe spinodal alloy which spinodally decomposes into a first Cu-rich phase and a second (Ni,Fe)-rich phase; and

the patterning of the spinodal alloy layer removes the first Cu-rich phase and leaves the second (Ni,Fe)-rich phase to form the islands for growing carbon nanotubes.

32. The method as in claim 29, wherein:

the patterned spinodal alloy layer is an array of islands, and the method further comprising;

forming a coating layer made of a single metal element or an alloy to cover the islands and areas of the substrate exposed between the islands; and

applying an annealing treatment to the coating layer to cause the coating layer to retract from the areas of the substrate between the islands so that the islands are separately covered by the coating layer leaving a portion of each area of the substrate between two adjacent islands free of the coating layer.

33. The method as in claim 32, further comprising:

applying an additional appealing treatment to cause alloying between the coating layer and each island covered by the coating layer.

34. The method as in claim 32, wherein:

the islands are made of a soft magnetic material; and

the coating layer is made of a hard magnetic material.

35. The method as in claim 29, further comprising:

forming one or more layers over the patterned spinodal alloy layer.

36. A method, comprising:

forming a spinodal alloy layer on a substrate, wherein the spinodal alloy layer comprises a plurality of alloy elements and, when the spinodal alloy layer is at a temperature within a spinodal decomposition temperature range for the two phases formed by the alloy elements, decomposes into two phases that are spatially separated and spatially interleaved in a spinodally decomposed periodic structure;

controlling a temperature of the spinodal alloy layer to be within the spinodal decomposition temperature range to form the spinodally decomposed periodic structure;

patterning the spinodal alloy layer in the spinodally decomposed periodic structure to partially remove the two phases by different amounts and hence to transform the spinodal alloy layer into a periodically patterned spinodal alloy layer made of the two phases; and

forming an additional structure on the patterned spinodal alloy layer.

37. The method as in claim 36, wherein:

the periodically patterned spinodal alloy layer has a contiguous and wavy topographic profile.

38. The method as in claim 36, wherein:

the spinodal alloy layer is Fe—

Cr—

Co, Fe—

Cr, Cu—

Ni—

Fe, Cu—

Ni—

Co, Cu—

Ni—

Ru, Al—

Si, or Al—

Si—

Co.

39. The method as in claim 38, wherein:

the additional structure on the patterned spinodal alloy layer is a perpendicular magnetic recording media structure which has a periodic pattern that matches the spinodally decomposed periodic structure of the patterned spinodal alloy layer.

40. The method as in claim 39, wherein:

the perpendicular magnetic recording media structure comprises one of FePt, CoPt, CoCrPt, Nd—

Fe—

B, [CoPd]n alternating multilayer, and [FePt]n alternating multilayer.

41. The method as in claim 39, wherein:

the perpendicular magnetic recording media structure comprises a nanocomposite of magnetic grains separated by walls of a non-magnetic oxide, nitride, carbide, or fluoride,

42. A method, comprising:

forming a long-range ordered spinodal alloy layer in the top portion of a substrate, wherein the spinodal alloy layer decomposes into two phases that are spatially separated and spatially interleaved in a spinodally decomposed periodic structure when at a temperature within a spinodal decomposition temperature range for the two phases;

controlling a temperature of the spinodal alloy layer within the substrate to be within the spinodal decomposition temperature range to form the spinodally decomposed periodic structure;

etching the spinodal alloy layer in the spinodally decomposed periodic structure to partially remove the two phases by different amounts and hence to transform the spinodal alloy layer into a patterned spinodal alloy layer made of the two phases; and

forming an additional structure on the patterned spinodal alloy layer.

43. The method as in claim 42, wherein:

the substrate is a single crystal substrate, and the long-range ordered spinodal alloy layer in the top portion of the substrate is formed by implanting metal ions into a top surface of the single crystal substrate to cause the metal ions and the substrate to react.

44. The method as in claim 42, wherein:

the substrate is a single crystal substrate, and

the long-range ordered spinodal alloy layer in the top portion of the substrate is formed by depositing a thin film of component elements of the spin alloy layer or the spinodal alloy layer on the single crystal substrate and providing an annealing treatment to allow the formation of a long-range ordered heteroepitaxially bonded spinodal alloy film on the surface of the single crystal substrate.

45. The method as in claim 42, wherein:

the substrate is a silicon substrate,

the metal ions are aluminum ions, and

the additional structure on the patterned spinodal alloy layer is a magnetic recording media structure which has a periodic pattern of a magnetic material and a non-magnetic material that matches the spinodally decomposed periodic structure of the patterned spinodal alloy layer.

46. The method as in claim 45, wherein:

the magnetic material is CoCrPt, and

the non-magnetic material is SiO2.

48. A device, comprising:

a substrate;

a spinodally decomposed periodic structure formed over the substrate; and

a periodic structure formed over the spinodally decomposed periodic structure.

49. The device as in claim 48, wherein:

the periodic structure formed over the spinodally decomposed periodic structure is an array of quantum dots that emit light under optical excitation.

50. The device as in claim 48, wherein:

the periodic structure formed over the spinodally decomposed periodic structure is an array of surface plasmon resonance elements.

51. The device as in claim 48, wherein:

the periodic structure formed over the spinodally decomposed periodic structure is an array of magnetic elements.

52. The device as in claim 51, wherein:

each magnetic element comprises a hard magnetic layer and a soft magnetic underlayer.

53. The device as in claim 48, wherein:

the periodic structure formed over the spinodally decomposed periodic structure is an array of memory elements that store data.

54. The device as in claim 53, wherein:

the memory elements are random access memory elements.

55. The device as in claim 53, wherein:

the memory elements are flash memory elements.

56. The device as in claim 48, wherein:

the periodic structure formed over the spinodally decomposed periodic structure is an array of transistors.

57. The device as in claim 48, wherein:

the periodic structure formed over the spinodally decomposed periodic structure is an array of switches.

58. The device as in claim 48, wherein:

the periodic structure formed over the spinodally decomposed periodic structure is an array of logic elements.

59. The device as in claim 48, further comprising:

an insulator matrix formed over the periodic structure; and

a second periodic structure in the insulator matrix.

60. The device as in claim 48, wherein:

the spinodally decomposed periodic structure is an array of catalyst islands for growing carbon nanotubes; and

the periodic structure is an array of islands of carbon nanotubes respectively attached to the catalyst islands.

61. The device as in claim 48, wherein:

the spinodally decomposed periodic structure is an array of catalyst islands for growing nanowires; and

the periodic structure is an array of islands of nanowires respectively attached to the catalyst islands.