Demultiplexer for a molecular wire crossbar network (MWCN DEMUX)

• US 6,256,767 B1
• Filed: 03/29/1999
• Issued: 07/03/2001
• Est. Priority Date: 03/29/1999
• Status: Expired due to Term

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Kuekes, Philip J., Williams, R. Stanley
• Primary Examiner(s): Smith, Matthew
• Assistant Examiner(s): Speight, Jibreel
• Application Number:
  US09/282,049
• Time in Patent Office: 827 Days
• Field of Search: 326/41, 700/121, 365/151, 427/126.3, 716/9, 257/23
• US Class Current: 365/151
• 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 13/0009 RRAM elements whose operation depends upon chemical change
• CPC Class Codes: G11C 13/02 using elements whose operation depends upon chemical change G11C13/0009 takes precedence
• CPC Class Codes: G11C 2213/14 Use of different molecule structures as storage states, e.g. part of molecule being rotated
• 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 8/00 Arrangements for selecting an address in a digital store for stores using transistors G11C11/407, G11C11/413
• CPC Class Codes: G11C 8/10 Decoders
• CPC Class Codes: Y10S 977/943 Information storage or retrieval using nanostructure

Abstract

A demultiplexer for a two-dimensional array of a plurality of nanometer-scale switches (molecular wire crossbar network) is disclosed. Each switch comprises a pair of crossed wires which form a junction where one wire crosses another and at least one connector species connecting said pair of crossed wires in said junction. The connector species comprises a bi-stable molecule. The demultiplexer comprises a plurality of address lines accessed by a first set of wires in the two-dimensional array by randomly forming contacts between each wire in the first set of wires to at least one of the address lines. The first set of wires crosses a second set of wires to form the junctions. The demultiplexer solves both the problems of data input and output to a molecular electronic system and also bridges the size gap between CMOS and molecules with an architecture that can scale up to extraordinarily large numbers of molecular devices. Further, the demultiplexer is very defect tolerant, and can work despite a large number of defects in the system.

Claims

1. At least one demultiplexer for a two-dimensional array of a plurality of nanometer-scale switches, each switch comprising a junction formed by a pair of crossed wires where one wire crosses another and at least one connector species connecting said pair of crossed wires in said junction, said at least one connector species comprising a bi-stable molecule, said demultiplexer is either (a) assembled in parallel and comprises a first set of wires in said two-dimensional array accessed by a plurality of address lines by randomly forming contacts between each wire in said first set of wires to at least one of said address lines, said first set of wires crossing a second set of wires to form said junctions or (b) assembled serially and comprises said first set of wires in said two-dimensional array accessed by said plurality of address lines by sequentially forming contacts between each wire in said first set of wires to at least one of said address lines, said first set of wires crossing said second set of wires to form said junctions.

2. The demultiplexer of claim 1 further including means for determining a unique address of each wire in said first set of wires using an AND array connected to at least one OR gate.

3. The demultiplexer of claim 1 further including means for determining a linear order of each wire in said first set of wires, by ascertaining which wire is next to which other wire.

4. The demultiplexer of claim 1 wherein said junction has a state that is altered by application of a voltage.

5. The demultiplexer of claim 1 wherein said junction has a state that is sensed by determining its resistance value.

6. The demultiplexer of claim 1 wherein said contact forms an asymmetric non-linear resistor.

7. The demultiplexer of claim 1 wherein said contact forms a diode.

8. The demultiplexer of claim 1 wherein said contact forms a transistor.

9. The demultiplexer of claim 1 wherein at least one of said two wires has a thickness that is about the same size as said at least one connector species, and over an order of magnitude longer than its diameter.

10. The demultiplexer of claim 9 wherein both of said two wires have a thickness that is about the same size as said at least one connector species.

11. The demultiplexer of claim 1 wherein both of said two wires have a thickness that ranges from sub-micrometer to micrometer.

12. The demultiplexer of claim 1 wherein said demultiplexer is serially assembled and there are N wires in said first set of wires, N wires in said second set of wires, and 2 log N address lines, where N is an integer.

13. The demultiplexer of claim 1 wherein said demultiplexer is assembled in parallel and there are N wires in said first set of wires and at least 4 log N address lines associated with said first set of wires, where N is an integer and said contact between a said wire of said first set of wires is either to a gate of a transistor on said address line or to a diode or to an asymmetric non-linear resistor.

14. The demultiplexer of claim 13 wherein said first set of wires extends from a first end to a second end, with said address lines near said first end and said two-dimensional array near said second end, and further including a CMOS driver at said first end and means for logically performing an OR function of said first set of wires at said second end.

15. The demultiplexer of claim 14 in which there are M groups of L wires each, where M×

L=N, each group including a said CMOS driver at said first end and a said logical OR means at said second end.

16. Two said demultiplexers of claim 1, a first said demultiplexer associated with said first set of wires in said two-dimensional array and a second said demultiplexer associated with said second set of wires in said two-dimensional array.

17. A method of fabricating at least one demultiplexer for a two-dimensional crossbar array comprising a plurality of crossed-wire devices, each device comprising a junction formed by a pair of crossed wires where a first wire is crossed by a second wire and at least one connector species connecting said pair of crossed wires in said junction, said at least one connector species comprising a bi-stable molecule, said junction having a functional dimension in nanometers, wherein said at least one connector species and said pair of crossed wires form an electrochemical cell, said method comprising (a) forming a first set of wires comprising a plurality of said first wires, (b) depositing said at least one connector species over at least a portion of said first set of wires, (c) forming a second set of wires comprising a plurality of said second wires over said first set of wires so as to form a said junction at each place where a second said wire crosses a first said wire, (d) forming a plurality of address lines outside of said array, and either (e1) randomly forming contacts between each wire in said second set of wires in said array and at least one of said address lines or (e2) sequentially forming contacts between each wire in said second set of wires in said array and at least one of said address lines.

18. The method of claim 17 further including providing means for determining a unique address of each wire in said first set of wires using an AND array connected to at least one OR gate.

19. The method of claim 17 further including providing means for determining a linear order of each wire in said first set of wires, by ascertaining which wire is next to which other wire.

20. The method of claim 19 wherein said ascertaining is accomplished by (a) cutting a said second wire with a first said wire, (b) testing all other said first wires to determine if they are above or below said first cutting wire, (c) reconnecting said cut second wire, (d) recursively repeating steps (a) through (c) for said -first wires above said cut wire, and (e) recursively repeating steps (a) through (c) for said first wires below said cut wire, until said order is determined.

21. The method of claim 17 wherein said junction has a state that is altered by application of a voltage.

22. The method of claim 17 wherein said junction has a state that is sensed by determining its resistance value.

23. The method of claim 17 wherein said contact forms an asymmetric non-linear resistor.

24. The method of claim 17 wherein said contact forms a diode.

25. The method of claim 17 wherein said contact forms a transistor.

26. The method of claim 17 wherein at least one of said two wires has a thickness that is about the same size as said at least one connector species, and over an order of magnitude longer than its diameter.

27. The method of claim 26 wherein both of said two wires have a thickness that is about the same size as said at least one connector species.

28. The method of claim 17 wherein both of said two wires have a thickness that ranges from sub-micrometer to micrometer.

29. The method of claim 17 wherein said demultiplexer is serially assembled and there are N wires in said first set of wires, N wires in said second set of wires, and 2 log N address lines, where N is an integer.

30. The method of claim 17 wherein said demultiplexer is assembled in parallel and there are L wires in said first set of wires, N wires in said second set of wires, and at least 4 log N address lines, where N is an integer and said contact between a said wire of said first set of wires is either to a gate of a transistor on said address line or to a diode or to an asymmetric non-linear resistor.

31. The method of claim 30 wherein said first set of wires extends from a first end to a second end, with said address lines near said first end and said two-dimensional array near said second end, and further including a CMOS driver at said first end and means for logically performing an OR function of said first set of wires at said second end.

32. The method of claim 31 in which there are M groups of L wires each, where M×

L=N, each group including a said CMOS driver at said first end and a said logical OR means at said second end.

33. The method of claim 17 wherein two said demultiplexers are formed, a first said demultiplexer associated with said first set of wires of said two-dimensional array and a second said demultiplexer associated with said second set of wires of said two-dimensional array.