Nanotube articles with adjustable electrical conductivity and methods of making the same

• US 20060276056A1
• Filed: 04/05/2006
• Published: 12/07/2006
• Est. Priority Date: 04/05/2005
• Status: Abandoned Application

• Current Assignee: Nantero Incorporated
• Original Assignee: Nantero Incorporated
• Inventors: Ward, Jonathan W., Segal, Brent M., Rueckes, Thomas
• Application Number:
  US11/398,126
• Publication Number:
  US 20060276056A1
• Time in Patent Office: Days
• US Class Current: 438/800
• 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 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: C01B 2202/02 Single-walled nanotubes
• CPC Class Codes: C01B 2202/06 Multi-walled nanotubes
• CPC Class Codes: C01B 2202/22 Electronic properties
• CPC Class Codes: C01B 32/168 After-treatment
• CPC Class Codes: C01B 32/18 Nanoonions; Nanoscrolls; Nanohorns; Nanocones; Nanowalls
• CPC Class Codes: H01C 17/0652 containing carbon or carbides
• CPC Class Codes: H01G 4/06 Solid dielectrics
• CPC Class Codes: H01L 21/76801 characterised by the formation and the after-treatment of the dielectrics, e.g. smoothing
• CPC Class Codes: H01L 21/76823 transforming an insulating layer into a conductive layer
• CPC Class Codes: H01L 21/76828 thermal treatment
• CPC Class Codes: H01L 21/76838 characterised by the formation and the after-treatment of the conductors etching for patterning the conductors H01L21/3213
• CPC Class Codes: H01L 21/76888 By rendering at least a portion of the conductor non conductive, e.g. oxidation
• CPC Class Codes: H01L 2221/1094 Conducting structures comprising nanotubes or nanowires
• CPC Class Codes: H01L 23/53276 containing carbon, e.g. fullerenes superconducting fullerenes H10N60/853
• CPC Class Codes: H01L 23/5329 Insulating materials
• CPC Class Codes: H01L 27/0802 Resistors only
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 : Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: Y10T 442/614 : Strand or fiber material specified as having microdimensions [i.e., microfiber]
• CPC Class Codes: Y10T 442/615 : Strand or fiber material is blended with another chemically different microfiber in the same layer
• CPC Class Codes: Y10T 442/696 : Including strand or fiber material which is stated to have specific attributes [e.g., heat or fire resistance, chemical or solvent resistance, high absorption for aqueous compositions, water solubility, heat shrinkability, etc.]
• CPC Class Codes: Y10T 442/697 : Containing at least two chemically different strand or fiber materials

Abstract

Nanotube articles having adjustable electrical conductivity, and methods of making the same. A patterned article includes conducting nanotubes that define a plurality of conductive pathways along the article, and also includes nanotubes of modified electrical conductivity. The modified nanotubes may electrically isolate the conducting nanotubes from other conductors. The nanotube segments may originally be semiconducting nanotubes, metallic nanotubes, nanotubes, single walled carbon nanotubes, multi-walled carbon nanotubes, or nanotubes entangled with nanotubes. The various segments may have different lengths and may include segments having a length shorter than the length of the article. A strapping material may be positioned to contact a portion of the plurality of nanotube segments. Such a strapping layer may also be used for making electrical contact to the nanotube fabric especially for electrical stitching to lower the overall resistance of the fabric.

Claims

1. A method of modifying the electrical resistance of individual nanostructures within a layer of said nanostructures, the method comprising:

providing a layer of nanostructures, said layer characterized by an electrical resistance; and

exposing the layer of nanostructures to a type and amount of reactive ions sufficient to increase the electrical resistance of the layer of nanostructures by a desired amount,

wherein the layer of nanostructures has a sufficiently low porosity to substantially expose each individual nanostructure within the layer to the reactive ions.

2. The method of claim 1, wherein exposure to said reactive ions increases the electrical resistance of substantially each individual nanostructure within the layer.

3. The method of claim 1, wherein exposure to said reactive ions increases the electrical resistance of the layer of nanostructures by a factor of at least 10.

4. The method of claim 1, wherein the layer of nanostructures comprises a non-woven fabric of nanostructures.

5. The method of claim 1, wherein each individual nanostructure within the layer lies substantially parallel to a substrate.

6. The method of claim 1, wherein the nanostructures comprise single-walled carbon nanotubes.

7. The method of claim 1, wherein the nanostructures comprise multi-walled carbon nanotubes.

8. The method of claim 1, wherein the nanostructures comprise nanowires.

9. The method of claim 1, further comprising heating the layer of nanostructures to reduce the electrical resistance of the layer of nanostructures.

10. The method of claim 1, further comprising depositing a patterned mask over a defined portion of the layer of nanostructures before exposing the layer to reactive ions.

11. The method of claim 10, wherein the defined portion of the layer is not exposed to the reactive ions and its electrical resistance is not increased.

12. The method of claim 10, wherein the defined portion of the layer forms an electrically conductive trace.

13. The method of claim 1, wherein the reactive ions are provided by at least one of CF₄, CHF₃, H₂, CH₄, SF₆, Ar, BCl₃, Cl₂, CCl₂F₂, SiCl₄, C₄F₈, HBr, and mixtures thereof.

14. The method of claim 1, wherein providing the layer of nanostructures comprises growing the nanostructures on a substrate.

15. The method of claim 1, wherein providing the layer of nanostructures comprises depositing pre-grown nanostructures on a substrate.

16. A nanotube fabric of adjustable electrical resistance, comprising:

a non-woven fabric of nanotubes, the non-woven fabric characterized by an electrical resistance,

wherein substantially each individual nanotube in the fabric is electrically resistive;

wherein the electrical resistance of substantially each individual nanotube in the fabric is increasable in response to reaction with a type and amount of reactive ions sufficient to increase the electrical resistance of the fabric by a desired amount; and

wherein the electrical resistance of substantially each individual nanotube in the fabric is reducible in response to a period and temperature of heating sufficient to reduce the electrical resistance of the fabric by a desired amount.

17. The fabric of claim 16, wherein the non-woven fabric of nanotubes forms an electrical insulator.

18. The fabric of claim 16, wherein the electrical resistance of the fabric is a function of a number of functional groups attached to substantially each individual nanotube of the fabric.

19. The fabric of claim 16, wherein reaction of the fabric with reactive ions at least partially functionalizes substantially each individual nanotube of the fabric.

20. The fabric of claim 16, wherein heating of the fabric at least partially drives functional groups off of substantially each individual nanotube of the fabric.

21. The fabric of claim 16, wherein heating of the fabric reduces the electrical resistance of the fabric below about 10,000 Ω

/square.

22. The fabric of claim 16, wherein the electrical resistance of the fabric is at least about 1 MΩ

/square.

23. The fabric of claim 16, wherein the electrical resistance of the fabric is at least about 1 TΩ

/square.

24. The fabric of claim 16, wherein substantially each individual nanotube of the fabric has an electrical resistance of about 1 MΩ

.

25. The fabric of claim 16, wherein the reactive ions are provided by a gas in a plasma.

26. The fabric of claim 16, wherein the gas comprises at least one of CF₄, CHF₃, H₂, CH₄, SF₆, Ar, BCl₃, Cl₂, CCl₂F₂, SiCl₄, C₄F₈, HBr, and mixtures thereof.

27. A patterned nanotube fabric, comprising:

a non-woven fabric of nanotubes, the fabric having a first defined region comprising nanotubes that substantially each individually are in a resistive state, and a second defined region comprising nanotubes that substantially each individually are in a conductive state.

28. The fabric of claim 27, wherein the first defined region has an electrical resistance that is at least about 10 times greater than that of the second defined region.

29. The fabric of claim 27, wherein the first defined region has an electrical resistance that is at least about 10⁶ times greater than that of the second defined region.

30. The fabric of claim 27, further comprising at least one nanotube having a relatively high resistance segment that overlaps the first defined region, and a relatively low resistance segment that overlaps the second defined region.

31. The fabric of claim 27, wherein the first defined region forms an electrical insulator.

32. The fabric of claim 27, wherein the second defined region forms an electrically conductive trace.

34. The fabric of claim 27, wherein the nanotubes of the second region form an electrical network of nanotubes that define a plurality of conductive pathways within the second defined region.

35. The fabric of claim 27, wherein the first region and second region touch each other along at least one border.

36. The fabric of claim 27, wherein the first region and second region are substantially coplanar.

37. The fabric of claim 27, wherein the non-woven fabric of nanotubes comprises substantially a monolayer of nanotubes.

38. The fabric of claim 27, wherein the non-woven fabric of nanotubes is porous.

39. The fabric of claim 27, wherein the non-woven fabric of nanotubes comprises substantially single-walled nanotubes.

40. The fabric of claim 27, wherein a lithographically patterned strapping material contacts at least a portion of the second defined region.

41. The fabric of claim 27, wherein the substrate is flexible.

42. The fabric of claim 27, wherein the substrate comprises at least one of plastic, glass, silicon, silicon oxide, or silicon nitride.

33. The fabric of claim 33, wherein the first defined region electrically insulates the electrically conductive trace from at least one conductor.

43. A circuit, comprising:

a first conductive electrode;

a second conductive electrode in spaced relation to the first electrode; and

a non-woven nanotube fabric of nanotubes substantially to fill the volume between the first and second electrodes, wherein substantially each individual nanotube of the fabric is in an electrically resistive state.

44. The circuit of claim 43, wherein the fabric electrically insulates the first electrode from the second electrode.

45. The circuit of claim 43, wherein the fabric substantially encapsulates the first and second electrodes.

46. The circuit of claim 43, wherein the fabric forms an interlayer dielectric between the first and second electrodes.

47. The circuit of claim 43, wherein at least one of the first and second electrodes comprises at least one of Ru, Ti, Cr, Al, Au, Pd, Ni, W, Cu, Mo, Ag, In, Ir, Pb, Sn, TiAu, TiCu, TiPd, PbIn, TiW, RuN, RuO, TiN, TaN, CoSi_x, TiSi_x, and mixtures thereof.

48. The circuit of claim 43, wherein at least one of the first and second electrodes comprises a non-woven fabric of conducting or semiconducting nanotubes.

49. A method of forming a patterned nanotube fabric, the method comprising:

providing a substrate having a top surface, the top surface having a patterned trench;

providing a non-woven nanotube fabric over the substrate, the fabric having a first portion that substantially fills the volume defined by the patterned trench and a second portion that substantially covers the rest of the top surface of the substrate; and

substantially removing the second portion of the fabric to leave the first portions of the non-woven nanotube fabric substantially filling the volume defined by the trench.

50. The method of claim 49, wherein removing the second portion of the fabric comprises mechanically polishing the top surface of the substrate.

51. The method of claim 49, wherein the removing the second portion of the fabric comprises spraying a solvent over the top surface of the substrate.

52. The method of claim 49, further comprising exposing the fabric to reactive ions of a type and amount sufficient to increase the electrical conductivity of the fabric by a desired amount.