ENCAPSULATING AND TRANSFERRING LOW DIMENSIONAL STRUCTURES

• US 20100012180A1
• Filed: 10/11/2007
• Published: 01/21/2010
• Est. Priority Date: 10/11/2006
• Status: Active Application

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Heffernan, Jonathan, Altebaeumer, Thomas Heinz-Helmut, Day, Stephen
• Application Number:
  US12/444,875
• Publication Number:
  US 20100012180A1
• Time in Patent Office: Days
• US Class Current: 136/256
• CPC Class Codes: B81C 2201/0191 Transfer of a layer from a carrier wafer to a device wafer
• CPC Class Codes: B81C 99/008 separating the processed structure from a mother substrate
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: H01L 21/02532 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02603 Nanowires
• CPC Class Codes: H01L 21/02642 Mask materials other than SiO2 or SiN
• CPC Class Codes: H01L 21/02645 Seed materials
• CPC Class Codes: H01L 21/02653 Vapour-liquid-solid growth
• CPC Class Codes: H01L 21/02664 Aftertreatments planarisation in general H01L21/304
• CPC Class Codes: H01L 29/0665 the shape of the body defining a nanostructure nanotechnology per se B82B
• CPC Class Codes: H01L 29/0673 oriented parallel to a substrate
• CPC Class Codes: H01L 29/0676 oriented perpendicular or at an angle to a substrate
• CPC Class Codes: H01L 29/42392 fully surrounding the channel, e.g. gate-all-around
• CPC Class Codes: H01L 29/66409 Unipolar field-effect transistors
• CPC Class Codes: H01L 29/78696 characterised by the structure of the channel, e.g. multichannel, transverse or longitudinal shape, length or width, doping structure, or the overlap or alignment between the channel and the gate, the source or the drain, or the contacting structure of the channel H01L29/78612 takes precedence; transistors having a drain offset region or a lightly doped drain [LDD] H01L29/78621
• CPC Class Codes: H01L 29/868 PIN diodes
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/54 having a particular shape
• CPC Class Codes: Y10T 428/24744 Longitudinal or transverse tubular cavity or cell

Abstract

A method of encapsulating low dimensional structures comprises forming a first group (3a) of low dimensional structures (1) and a second group (3b) of low dimensional structures (1) on a first substrate. The first group (3a) of low dimensional structures (1) and the second group (3b) of low dimensional structures (1) are encapsulated in a matrix (5), with the first group (3a) of low dimensional structures (1) being encapsulated separately from the second group (3b) of low dimensional structures (1). After encapsulation, the first group (3a) of low dimensional structures (1) may be separated from the second group (3b) of low dimensional structures (1). Each group may then be processed, for example by transfer to a second substrate (7). The number of low dimensional structures in a group, and the aspect ratio of a group is defined when the low dimensional structures are formed, and can therefore be controlled more accurately than in a conventional method in which groups are defined using a patterning technique.

Claims

1. A method of encapsulating low dimensional structures, the method comprising:

forming a first group of low dimensional structures and a second group of low dimensional structures on a first substrate; and

encapsulating the first group of low dimensional structures and the second group of low dimensional structures in a matrix, the first group of low dimensional structures being encapsulated separately from the second group of low dimensional structures.

2. A method as claimed in claim 1 and comprising encapsulating the first and second groups of low dimensional structures such that the matrix encapsulating the first group of low dimensional structures is continuous with the matrix encapsulating the second group of low dimensional structures only near the first substrate.

3. A method as claimed in claim 1 and comprising encapsulating the first and second groups of low dimensional structures such that the matrix encapsulating the first group of low dimensional structures is not continuous with the material encapsulating the second group of low dimensional structures.

4. A method as claimed in claim 1 and comprising the further step of separating the matrix encapsulating the first group of low dimensional structures from the matrix encapsulating the second group of low dimensional structures.

5. A method as claimed in claim 3 and comprising the further step of transferring at least one of the first group of low dimensional structures and the second group of low dimensional structures to a second substrate.

6. A method as claimed in claim 3 and comprising the further step of re-orienting and/or re-positioning at least one of the first group of low dimensional structures and the second group of low dimensional structures on the first substrate.

7. A method as claimed in claim 1, wherein the spacing between the first group and the second group is greater than the maximum spacing between adjacent low dimensional structures in any of the groups.

8. A method as claimed in claim 1 wherein the low dimensional structures in each group are arranged along a respective line.

9. A method as claimed in claim 8 wherein the low dimensional structures in each group are arranged along a respective straight or substantially straight line.

10. A method as claimed in claim 1 wherein the low dimensional structures in each group are regularly spaced.

11. A method as claimed in claim 1 wherein the low dimensional structures in each group are irregularly spaced.

12. A method as claimed in claim 1 and further comprising the steps of:

forming a layer over the first substrate; and

defining a plurality of holes in the layer so as to expose the first substrate; and

wherein the step of forming the first and second groups of low dimensional structures comprises forming each structure at a respective hole in the layer.

13. A method as claimed in claim 12 and comprising the further step of removing the layer after forming the first and second groups of low dimensional structures.

16. A method as claimed in claim 12 wherein the layer is a silica or silicon nitride layer.

17. A method as claimed in claim 1 and comprising the further step of removing at least a portion of the matrix.

18. A method as claimed in claim 17 wherein the step of removing at least a portion of the matrix comprises planarising at least one surface of the matrix.

19. A method as claimed in claim 17 wherein the step of removing at least a portion of the matrix comprises exposing at least a portion of at least one low dimensional structure.

20. A method as claimed in claim 1 wherein forming the low dimensional structures on the first substrate comprises forming the low dimensional structures with a first substantially unidirectional orientation.

21. A method as claimed in claim 20 wherein forming the low dimensional structures on the first substrate comprises forming elongate structures with their longitudinal axes substantially perpendicular to the first substrate.

23. A method as claimed in claim 21 wherein the transferring step comprises transferring the elongate structures to the second substrate with their longitudinal axes substantially parallel to the first substrate,

and comprising encapsulating the first and second groups of low dimensional structures such that the matrix encapsulating the first group of low dimensional structures is not continuous with the material encapsulating the second group of low dimensional structures

and comprising the further step of transferring at least one of the first group of low dimensional structures and the second group of low dimensional structures to a second substrate.

24. A method as claimed in claim 1 wherein the step of encapsulating the low dimensional structures comprises forming at least a layer of a first encapsulant material over the low dimensional structures.

25. A method as claimed in claim 1 wherein the step of encapsulating the low dimensional structures comprises forming at least a layer of a first encapsulant material over the low dimensional structures and forming a layer of a second encapsulant material different from the first encapsulant material over the layer of the first encapsulant material.

26. A method as claimed in claim 1 wherein the step of encapsulating the low dimensional structures comprises forming at least a layer of a first encapsulant material over the low dimensional structures, and transforming at least part of the first encapsulant material to a second encapsulant material different from the first encapsulant material.

66. A method as claimed in claim 4 and comprising the further step of transferring at least one of the first group of low dimensional structures and the second group of low dimensional structures to a second substrate.

67. A method as claimed in claim 4 and comprising the further step of re-orienting and/or re-positioning at least one of the first group of low dimensional structures and the second group of low dimensional structures on the first substrate.

78. A method as claimed in claim 21 wherein the transferring step comprises transferring the elongate structures to the second substrate with their longitudinal axes substantially parallel to the first substrate;

and comprising the further step of separating the matrix encapsulating the first group of low dimensional structures from the matrix encapsulating the second group of low dimensional structures;

and comprising the further step of transferring at least one of the first group of low dimensional structures and the second group of low dimensional structures to a second substrate.

14. A method comprising:

forming a layer over a first substrate;

defining a plurality of holes in the layer so as to expose the substrate;

forming a plurality of low dimensional structures over the substrate, each structure at a respective hole in the layer;

encapsulating the low dimensional structures in a matrix; and

removing the layer.

15. A method as claimed in claim 14 and comprising the further step of transferring the low dimensional structures to a second substrate.

22. A method as claimed in claim 20 when dependent directly or indirectly from claim 5 or claim 15 comprising encapsulating the first and second groups of low dimensional structures such that the matrix encapsulating the first group of low dimensional structures is not continuous with the material encapsulating the second group of low dimensional structures, comprising the further step of transferring at least one of the first group of low dimensional structures and the second group of low dimensional structures to a second substrate, and wherein the transferring step comprises transferring the low dimensional structures to the second substrate with a second substantially unidirectional orientation different from the first substantially unidirectional orientation.

68. A method as claimed in claim 14 wherein the layer is a silica or silicon nitride layer.

69. A method as claimed in claim 14 and comprising the further step of removing at least a portion of the matrix.

70. A method as claimed in claim 14 wherein forming the low dimensional structures on the first substrate comprises forming the low dimensional structures with a first substantially unidirectional orientation.

71. A method as claimed in claim 14 wherein the step of encapsulating the low dimensional structures comprises forming at least a layer of a first encapsulant material over the low dimensional structures.

72. A method as claimed in claim 14 wherein the step of encapsulating the low dimensional structures comprises forming at least a layer of a first encapsulant material over the low dimensional structures and forming a layer of a second encapsulant material different from the first encapsulant material over the layer of the first encapsulant material.

73. A method as claimed in claim 14 wherein the step of encapsulating the low dimensional structures comprises forming at least a layer of a first encapsulant material over the low dimensional structures, and transforming at least part of the first encapsulant material to a second encapsulant material different from the first encapsulant material.

74. A method as claimed in claim 69 wherein the step of removing at least a portion of the matrix comprises planarising at least one surface of the matrix.

75. A method as claimed in claim 69 wherein the step of removing at least a portion of the matrix comprises exposing at least a portion of at least one low dimensional structure.

76. A method as claimed in claim 70 wherein forming the low dimensional structures on the first substrate comprises forming elongate structures with their longitudinal axes substantially perpendicular to the first substrate.

77. A method as claimed in claim 70 comprising the further step of transferring the low dimensional structures to a second substrate, wherein the transferring step comprises transferring the low dimensional structures to the second substrate with a second substantially unidirectional orientation different from the first substantially unidirectional orientation.

79. A method as claimed in claim 76 wherein the transferring step comprises transferring the elongate structures to the second substrate with their longitudinal axes substantially parallel to the first substrate;

and comprising the further step of transferring the low dimensional structures to a second substrate.

27-34. -34. (canceled)

35. A composite structure comprising:

a matrix; and

a plurality of low dimensional structures embedded in the matrix;

wherein the low dimensional structures are arranged along at least a line extending generally perpendicular to an axis of the low dimensional structures; and

wherein the low dimensional structures are arranged along a substantially straight line; and

wherein the low dimensional structures are substantially unidirectionally oriented; and

wherein the low dimensional structures lie substantially within a common plane, where said common plane is substantially parallel to at least one side face of the composite structure; and

wherein the low dimensional structures are substantially straight; and

wherein the matrix is a material compatible with a substantially isotropic deposition process.

37. A structure as claimed in claim 35 wherein the maximum separation between any two adjacent neighbouring structures is less than the smallest dimension of the matrix.

39. A structure as claimed in claim 35 wherein the low dimensional structures are regularly spaced.

40. A structure as claimed in claim 35 wherein the low dimensional structures are irregularly spaced.

41. A structure as claimed in claim 35 wherein the low dimensional structures are elongate structures arranged along at least a line extending generally perpendicular to the longitudinal axes of the low dimensional structures.

42. A structure as claimed in claim 35 wherein at least a portion of one or more of the low dimensional structures is not covered by the matrix.

43. A structure as claimed in claim 35 wherein at least one of the low dimensional structures is not covered by the matrix along substantially its entire length.

44. A structure as claimed in claim 35 wherein the matrix comprises at least a layer of a first encapsulant material disposed over each of the low dimensional structures.

45. A structure as claimed in claim 35 wherein the matrix comprises at least a layer of a first encapsulant material disposed over each of the low dimensional structures and a layer of a second encapsulant material different from the first encapsulant material disposed over the first encapsulant material.

52. A structure as claimed in claim 42 and comprising a transistor.

53. A structure as claimed in claim 52 wherein the matrix encapsulates an intermediate portion of the low dimensional structures but does not encapsulate each end portion of the low dimensional structures;

wherein first end portions of the low dimensional structures are electrically connected to a first electrical contact;

wherein second end portions of the low dimensional structures are electrically connected to a second electrical contact; and

wherein the matrix is electrically connected to a third electrical contact.

54. A structure as claimed in claim 35 wherein the structure is a light emissive structure.

55. A structure as claimed in claim 54 and comprising means for driving the low-dimensional structures to emit light.

56. A structure as claimed in claim 55 and comprising means for electrically driving the low-dimensional structures to emit light.

57. A structure as claimed in claim 54 wherein the encapsulant material absorbs light, in use, thereby to cause the low-dimensional structures to re-emit light.

58. A structure as claimed in claim 35 wherein the structure is a light sensing structure.

59. A structure as claimed in claim 35 wherein the structure is a photo-voltaic structure.

60. A structure as claimed in claim 58 wherein the encapsulant material is arranged to re-direct incident light onto the low-dimensional structures.

61. A structure as claimed in claim 35 wherein the structure comprises a memory device.

62. A structure as claimed in claim 61 wherein matrix comprises, in sequence:

a first electrically insulating layer;

a first electrically conductive layer;

a second electrically insulating layer; and

a second electrically conductive layer;

wherein the first electrically insulating layer around a low-dimensional structure is separate from the first electrically insulating layer around an adjacent low-dimensional structure;

wherein the first electrically conductive layer around a low-dimensional structure is separate from the first electrically conductive layer around an adjacent low-dimensional structure;

wherein the second electrically insulating layer around a low-dimensional structure is continuous with the second electrically insulating layer around an adjacent low-dimensional structure; and

wherein the second electrically conductive layer around a low-dimensional structure is continuous with the second electrically conductive layer around an adjacent low-dimensional structure.

63. A structure as claimed in claim 35 wherein the structure comprises a first group of low-dimensional structures encapsulated in a first matrix and a second group of low-dimensional structures encapsulated in a second matrix, the first group of low-dimensional structures being opposed to the second group of low dimensional structures;

and wherein the first matrix and the second matrix are electrically conductive.

64. A structure as claimed in claim 35 wherein the aspect ratio of the composite structure is greater than 10:

1.

65. A structure as claimed in claim 35 wherein the matrix possess properties essential to the performance of subsequent devices in which the structure is incorporated.

80. A structure as claimed in claim 59 wherein the encapsulant material is arranged to re-direct incident light onto the low-dimensional structures.

36. (canceled)

38. (canceled)

46-51. -51. (canceled)