METHODS FOR PASSIVATING A CARBONIC NANOLAYER

• US 20110163290A1
• Filed: 10/22/2010
• Published: 07/07/2011
• Est. Priority Date: 10/23/2009
• Status: Active Grant

• Current Assignee: ZEON Corporation
• Original Assignee: Nantero Incorporated
• Inventors: Sen, Rahul, Manning, H. Montgomery, Rueckes, Thomas
• Granted Patent: US 8,551,806 B2
• Time in Patent Office: Days
• US Class Current: 257/9
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: G11C 2213/16 Memory cell being a nanotube, e.g. suspended nanotube
• CPC Class Codes: H01L 27/101 including resistors or capacitors only

Abstract

Methods for passivating a carbonic nanolayer (that is, material layers comprised of low dimensional carbon structures with delocalized electrons such as carbon nanotubes and nano-scopic graphene flecks) to prevent or otherwise limit the encroachment of another material layer are disclosed. In some embodiments, a sacrificial material is implanted within a porous carbonic nanolayer to fill in the voids within the porous carbonic nanolayer while one or more other material layers are applied over or alongside the carbonic nanolayer. Once the other material layers are in place, the sacrificial material is removed. In other embodiments, a non-sacrificial filler material (selected and deposited in such a way as to not impair the switching function of the carbonic nanolayer) is used to form a barrier layer within a carbonic nanolayer. In other embodiments, carbon structures are combined with and nanoscopic particles to limit the porosity of a carbonic nanolayer.

Claims

1. A carbonic nanolayer based device, comprising:

a carbonic nanolayer comprising a plurality of carbon structures, said carbonic nanolayer having a first side and a second side;

a material layer;

wherein said carbonic nanolayer and said material layer have longitudinal axes that are substantially parallel; and

wherein the density of said carbonic nanolayer is selected such as to limit the encroachment of said material layer into said carbonic nanolayer.

2. The carbonic nanolayer based device of claim 1 wherein said carbonic nanolayer is comprised of a first sub-layer and a second sub-layer, the density of said first sub-layer being selected such as to limit the encroachment of said material layer into said second sub-layer.

3. The carbonic nanolayer based device of claim 1 wherein said carbon structures are carbon nanotubes.

4. The carbonic nanolayer based device of claim 3 wherein the density of said carbonic nanolayer is selected by limiting the length of said carbon nanotubes.

5. The carbonic nanolayer based device of claim 4 wherein the length of said carbon nanotubes is less than about 500 nm.

6. The carbonic nanolayer based device of claim 3 wherein at least a portion of said carbon nanotubes are rafted.

7. The carbonic nanolayer based device of claim 1 wherein said carbonic nanolayer is formed via one of a spin coating process, a spray coating process, or a dip coating process.

8. The carbonic nanolayer based device of claim 1 wherein said carbon structures are selected from the group consisting of single wall carbon nanotubes, multi-wall carbon nanotubes, functionalized carbon nanotubes, oxidized carbon nanotubes, buckyballs, graphene sheets, nano-scopic graphene flecks, and graphene oxide.

9. The carbonic nanolayer based device of claim 1 wherein said material layer is in direct physical contact with said carbonic nanolayer.

10. The carbonic nanolayer based device of claim 1 wherein said material layer and said carbonic nanolayer are in different planes.

11. A method for forming a carbonic nanolayer based device, comprising:

forming a carbonic nanolayer, said carbonic nanolayer comprising a plurality of carbon structures;

flowing a filler material over said carbonic nanolayer such that said filler material penetrates said carbonic nanolayer to form a barrier layer; and

depositing a material layer such that said carbonic nanolayer and said second material layer have longitudinal axes that are substantially parallel.

12. The method of claim 11 wherein said barrier layer limits the encroachment of said material layer into said carbonic nanolayer.

13. The method of claim 11 further comprising etching away excess filler material after said flowing and prior to said depositing.

14. The method of claim 11 further comprising etching at least one of said material layer, said barrier layer, and said carbonic nanolayer to form a plurality of individual carbonic nanolayer based devices prior to said volatizing.

15. The method of claim 14 wherein said barrier layer provides structural support to said carbonic nanolayer during said etching.

16. The method of claim 11 further comprising volatizing and removing at least a portion of said barrier layer after said step of depositing.

17. The method of claim 16 wherein said material layer is a non-hermetic material.

18. The method of claim 17 wherein said non-hermetic material comprises a physical vapor deposited titanium nitride (TiN), tantalum nitride (TaN), or tungsten (W).

19. The method of claim 17 wherein at least a portion of said barrier layer is volatized and removed through said non-hermetic material.

20. The method of claim 16 further comprising at least partially encapsulating at least one of said material layer, said barrier layer, and said carbonic nanolayer within a dielectric material layer prior to said volatizing.

21. The method of claim 20 wherein said dielectric material layer comprises silicon nitride (SiN).

22. The method of claim 16 wherein said volatizing is performed using a wet etch process.

23. The method of claim 22 wherein said wet etch process is a hydrofluoric etch process.

24. The method of claim 11 wherein said filler material is selected from the group consisting of phosphosilicate glass (PSG) oxide, amorphous carbon, silicon dioxide (SiO2), and silicon nitride (SiN).

25. The method of claim 11 where said filler material is a porous dielectric.

26. The method of claim 25 wherein said porous dielectric is one of silicon dioxide aerogel or porous silica.

27. The method of claim 11 wherein said barrier layer is formed through a room temperature physical vapor deposition (RTPVD) process.

28. The method of claim 27 wherein said filler material comprises tetraethyl orthosilicate (TEOS).

29. The method of claim 11 wherein said barrier layer is formed through a non-directional sputter deposition process.

30. The method of claim 29 wherein said filler material comprises titanium nitride (TiN).

31. The method of claim 11 wherein said carbon structures are selected from the group consisting of single wall carbon nanotubes, multi-wall carbon nanotubes, functionalized carbon nanotubes, oxidized carbon nanotubes, buckyballs, graphene sheets, nano-scopic graphene flecks, and graphene oxide.

32. A method for forming a carbonic nanolayer based device, comprising:

combining a first volume of carbon structures and a second volume of nanoscopic particles in a liquid medium to form an application solution;

depositing said application solution over a first material layer as to form a composite layer, said composite layer comprising a mixture of said carbon structures and said nanoscopic particles; and

depositing a second material layer such that said composite layer and said second material layer have longitudinal axes that are substantially parallel.

33. The method of claim 32 wherein said carbon structures are selected from the group consisting of single wall carbon nanotubes, multi-wall carbon nanotubes, functionalized carbon nanotubes, oxidized carbon nanotubes, buckyballs, graphene sheets, nano-scopic graphene flecks, and graphene oxide.

34. The method of claim 32 wherein said second volume of nanoscopic particles are comprised of at least one material selected from the group consisting of silicon oxide, silicon nitride, amorphous carbon, and multi-walled carbon nanotubes.

35. The method of claim 32 wherein substantially all of said nanoscopic particles within said second volume fall within a predetermined volume tolerance.

36. The method of claim 32 wherein at least one of the magnitude of said first volume of carbon structures, the magnitude of said second volume of nanoscopic particles, and the volume of said liquid medium is selected to obtain a desired degree of porosity within said composite layer.

37. The method of claim 32, wherein said first volume of carbon structures form a matrix phase and said second volume of nanoscopic particles form a discrete phase.

38. The method of claim 32, wherein said second volume of nanoscopic particles form a matrix phase and said first volume of carbon structures form a discrete phase.

39. The method of claim 32, wherein said first volume of carbon structures and said second volume of nanoscopic particles form interconnected matrix phases.

40. The method of claim 32, wherein said composite layer has less than about 10¹¹ metal atoms/cm².

41. The method of claim 32 further comprising flowing a filler material over said composite layer such that said filler material penetrates said composite layer to form a barrier layer.

42. The method of claim 41 wherein said barrier layer limits the encroachment of said material layer into said composite layer.

43. The method of claim 41 further comprising etching away excess filler material after said flowing.

44. The method of claim 41 wherein said barrier layer provides structural support to said composite layer.

45. The method of claim 41 wherein said filler material is selected from the group consisting of amorphous carbon, silicon dioxide (SiO2), and silicon nitride (SiN).

46. The method of claim 41 wherein said barrier layer is formed through a room temperature physical vapor deposition (RTPVD) process.

47. The method of claim 46 wherein said filler material comprises tetraethyl orthosilicate (TEOS).

48. The method of claim 41 wherein said barrier layer is formed through a non-directional sputter deposition process.

49. The method of claim 48 wherein said filler material comprises titanium nitride (TiN).

50. The method of claim 32 wherein at least one of said first material layer and said second material layer are flexible.

51. A nanotube switching device, comprising:

a first conductive element;

a second conductive element;

a nanotube fabric layer comprising a plurality of individual nanotube elements, said nanotube fabric layer having a first side and a second side;

wherein said first side of said nanotube fabric layer is electrical coupled to said first conductive element and said second side of said nanotube fabric layer is electrically coupled to said second conductive element; and

wherein the density of said nanotube fabric layer is selected such as to limit the encroachment of at least one of said first conductive element and said second conductive element into said nanotube fabric layer.

52. The nanotube switching device of claim 51 wherein the density of said nanotube fabric layer is selected by limiting the length of said individual nanotube elements.

53. The nanotube switching device of claim 52 wherein the length of said individual nanotube elements is limited to about 0.4 μ

m.

54. The nanotube switching device of claim 51 wherein said nanotube fabric layer is deposited via a spin coating process.

55. The nanotube switching device of claim 51 wherein said nanotube fabric layer is deposited via a dip coating process.

56. The nanotube switching device of claim 51 wherein said nanotube fabric layer is deposited in such a way that at least a portion said plurality of individual nanotube elements are rafted.

57. The nanotube switching device of claim 51 wherein at least one of said first conductive element and said second conductive element is flexible.