Methods for forming nanotube fabric layers with increased density

• US 10,084,138 B2
• Filed: 11/21/2016
• Issued: 09/25/2018
• Est. Priority Date: 10/23/2009
• Status: Active Grant

• Current Assignee: ZEON Corporation
• Original Assignee: Nantero Incorporated
• Inventors: Rueckes, Thomas, Manning, H. Montgomery, Sen, Rahul
• Primary Examiner(s): KUSUMAKAR, KAREN M
• Application Number:
  US15/357,003
• Publication Number:
  US 20170069846A1
• Time in Patent Office: 673 Days
• 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 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: H01L 21/02203 the layer being porous
• CPC Class Codes: H01L 21/02527 Carbon, e.g. diamond-like carbon
• CPC Class Codes: H01L 21/02606 Nanotubes carbon nanotubes H10K85/211
• CPC Class Codes: H01L 21/02628 using solutions
• CPC Class Codes: H01L 29/0665 the shape of the body defining a nanostructure nanotechnology per se B82B
• CPC Class Codes: H01L 29/0669 Nanowires or nanotubes carbon nanotubes as material of solid-state device active part H10K85/211
• CPC Class Codes: H01L 29/1029 of field-effect transistors
• CPC Class Codes: H01L 29/1606 Graphene
• CPC Class Codes: H10K 10/50 Bistable switching devices
• CPC Class Codes: H10K 10/88 Passivation; Containers; Encapsulations
• CPC Class Codes: H10K 71/12 using liquid deposition, e.g. spin coating
• CPC Class Codes: H10K 71/15 characterised by the solvent used
• CPC Class Codes: H10K 85/221 Carbon nanotubes
• CPC Class Codes: H10N 70/021 Formation of switching materials, e.g. deposition of layers
• CPC Class Codes: H10N 70/826 adapted for essentially vertical current flow, e.g. sandwich or pillar type devices
• CPC Class Codes: H10N 70/8845 Carbon or carbides
• CPC Class Codes: Y10S 977/842 for carbon nanotubes or fullerenes

Abstract

Methods for passivating a nanotube fabric layer within a nanotube switching device to prevent or otherwise limit the encroachment of an adjacent material layer are disclosed. In some embodiments, a sacrificial material is implanted within a porous nanotube fabric layer to fill in the voids within the porous nanotube fabric layer while one or more other material layers are applied adjacent to the nanotube fabric layer. 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 nanotube fabric layer) is used to form a barrier layer within a nanotube fabric layer. In other embodiments, individual nanotube elements are combined with and nanoscopic particles to limit the porosity of a nanotube fabric layer.

Claims

1. A method for forming a multilayer nanotube fabric, comprising:

forming a first nanotube application solution, said first nanotube application solution comprising a first plurality of nanotube elements suspended in a solvent;

depositing said first nanotube application solution over a material layer to form a first nanotube fabric layer having a first density;

selecting a second plurality of nanotube elements, said second plurality of nanotube elements having a length below a selected limit;

forming a second nanotube application solution, said second nanotube application solution comprising said selected second plurality of nanotube elements suspended in a solvent;

depositing said second nanotube application solution over said first nanotube fabric layer to form a second nanotube fabric layer with a selected second density,

wherein said first nanotube fabric layer and said second nanotube fabric layer form a multilayer nanotube fabric; and

wherein said second density is selected by selecting the length of said second plurality of nanotube elements, and said second density of said second nanotube fabric layer is sufficient to passivate said multilayer nanotube fabric.

2. The method of claim 1 wherein said selected density limits the encroachment of a second material layer formed over or adjacent to said multilayer nanotube fabric into said multilayer nanotube fabric.

3. The method of claim 1 wherein said length of second plurality of nanotube elements is limited to less than about 500 nm.

4. The method of claim 1 wherein said length of second plurality of nanotube elements is limited to less than about 100 nm.

5. The method of claim 1 wherein said first nanotube application solution and said second nanotube application solutions are deposited using one of a spin coating process, a spray coating process, or a dip coating process.

6. The method of claim 1 wherein said nanotube elements are carbon nanotubes.

7. The method of claim 1 wherein said solvent is one of dimethylformamide, n-methylpyrollidinone, n-methyl formamide, ethyl lactate, alcohol, or water.

8. The method of claim 1 wherein said second nanotube fabric layer has a substantially uniform density.

9. The method of claim 1 wherein said first density is selected to increase the switching function of said first nanotube fabric layer.