Electromechanical memory array using nanotube ribbons and method for making same

• US 8,058,089 B2
• Filed: 03/31/2009
• Issued: 11/15/2011
• Est. Priority Date: 07/25/2001
• Status: Expired due to Fees

• Current Assignee: Nantero Incorporated
• Original Assignee: Nantero Incorporated
• Inventors: Brock, Darren K., Segal, Brent M., Rueckes, Thomas
• Primary Examiner(s): COLEMAN, WILLIAM D
• Application Number:
  US12/415,247
• Publication Number:
  US 20090283803A1
• Time in Patent Office: 959 Days
• Field of Search: 438/48, 977/856, 977/888, 257/415
• US Class Current: 438/48
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: G11C 13/025 using fullerenes, e.g. C60, or nanotubes, e.g. carbon or silicon nanotubes
• CPC Class Codes: G11C 2213/16 Memory cell being a nanotube, e.g. suspended nanotube
• CPC Class Codes: G11C 2213/81 Array wherein the array conductors, e.g. word lines, bit lines, are made of nanowires
• CPC Class Codes: G11C 23/00 Digital stores characterised by movement of mechanical parts to effect storage, e.g. using balls; Storage elements therefor
• CPC Class Codes: H01H 1/0094 Switches making use of nanoelectromechanical systems [NEMS]
• 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: 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: Y10S 977/724 Devices having flexible or movable element
• CPC Class Codes: Y10S 977/742 Carbon nanotubes, CNTs
• CPC Class Codes: Y10S 977/796 for electrical or electronic purpose
• CPC Class Codes: Y10S 977/856 including etching/cutting
• CPC Class Codes: Y10S 977/888 Shaping or removal of materials, e.g. etching
• CPC Class Codes: Y10S 977/943 Information storage or retrieval using nanostructure
• CPC Class Codes: Y10T 428/24893 including particulate material
• CPC Class Codes: Y10T 428/24917 including metal layer

Abstract

Electromechanical circuits, such as memory cells, and methods for making same are disclosed. The circuits include a structure having electrically conductive traces and supports extending from a surface of the substrate, and nanotube ribbons suspended by the supports that cross the electrically conductive traces, wherein each ribbon comprises one or more nanotubes. The electro-mechanical circuit elements are made by providing a structure having electrically conductive traces and supports, in which the supports extend from a surface of the substrate. A layer of nanotubes is provided over the supports, and portions of the layer of nanotubes are selectively removed to form ribbons of nanotubes that cross the electrically conductive traces. Each ribbon includes one or more nanotubes.

Claims

1. A method of making electro-mechanical circuit elements comprising the acts of

providing a structure having electrically conductive traces and supports, the supports extending from a surface of the substrate;

providing a layer of non-woven nanotube fabric over the supports; and

selectively removing portions of the layer of non-woven nanotube fabric to form nanotube ribbons that cross the electrically conductive traces.

2. The method of claim 1 wherein the act of providing a structure provides a structure in which the electrically conductive traces are doped silicon traces.

3. The method of claim 1 wherein the act of providing a structure provides a structure in which the electrically conductive traces are nanotubes.

4. The method of claim 1 wherein the act of providing a structure provides a structure in which the electrically conductive traces are ribbons of nanotubes.

5. The method of claim 1 wherein the act of providing a structure provides a structure in which the support structures are formed as rows of material and wherein the electrically conductive traces are substantially parallel to the rows.

6. The method of claim 1 wherein the traces are separated from the supports.

7. The method of claim 1 wherein the traces contact the supports.

8. The method of claim 1 wherein the act of providing a structure provides a structure in which the supports are made from silicon nitride.

9. The method of claim 1 wherein the act of providing a structure provides a structure in which the electrically conductive traces are over a layer of insulating material to electrically isolate the traces relative to one another.

10. The method of claim 1 wherein the act of providing a structure provides a structure in which the electrically conductive traces are each over insulating material to electrically isolate the traces.

11. The method of claim 1 wherein the act of providing a layer of nanotubes provides a non-woven fabric of nanotubes.

12. The method of claim 1 in which the act of selectively removing includes the act of patterning and etching a layer of nanotubes to form the ribbons.

13. The method of claim 1 wherein the layer of nanotubes is substantially a monolayer.

14. The method of claim 5 wherein the traces are separated from the supports.

15. The method of claim 5 wherein the traces contact the supports.

16. The method of claim 11 in which the fabric is grown on the structure.

17. The method of claim 11 in which the structure includes a sacrificial layer of material over the traces and in which the fabric is grown over the sacrificial layer.

18. The method of claim 11 in which the act of selectively removing includes the act of patterning and etching the fabric of nanotubes to form the ribbons.

19. The method of claim 12 wherein the act of patterning and etching uses etchants that diffuse through the fabric.

20. The method of claim 16 in which the structure is treated with a catalyst to facilitate the growth of the fabric.

21. The method of claim 16 wherein the growth of nanotubes is substantially unrestrained over the surface of the structure.

22. The method of claim 17 in which an upper surface of the sacrificial layer is treated with a catalyst to facilitate the growth of the fabric.