Nanotube-based transfer devices and related circuits

• US 20050279988A1
• Filed: 01/10/2005
• Published: 12/22/2005
• Est. Priority Date: 06/18/2004
• Status: Active Grant

• Current Assignee: Nantero Incorporated
• Original Assignee: Nantero Incorporated
• Inventors: Bertin, Claude L.
• Granted Patent: US 7,652,342 B2
• Time in Patent Office: Days
• US Class Current: 257/9
• 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: H10K 10/466 Lateral bottom-gate IGFETs comprising only a single gate
• CPC Class Codes: H10K 85/221 Carbon nanotubes
• CPC Class Codes: H10K 85/615 Polycyclic condensed aromatic hydrocarbons, e.g. anthracene

Abstract

Nanotube transfer devices controllably form a nanotube-based electrically conductive channel between a first node and a second node under the control of a control structure. A control structure induces a nanotube channel element to deflect so as to form and unform the conductive channel between the nodes. The nanotube channel element is not in permanent electrical contact with either the first node or the second node. The nanotube channel element may have a floating potential in certain states of the device. Each output node may be connected to an arbitrary network of electrical components. The nanotube transfer device may be volatile or non-volatile. In preferred embodiments, the nanotube transfer device is a three-terminal device or a four-terminal device. Electrical circuits are provided that ensure proper switching of nanotube transfer devices interconnected with arbitrary circuits. The circuits may overdrive the control structure to induce the desired state of channel formation.

Claims

1. A nanotube transfer device, comprising:

a first output node for electrical connection to a first arbitrary network;

a second output node for electrical connection to a second arbitrary network;

a nanotube channel element including at least one electrically conductive nanotube, said nanotube channel element being constructed and arranged so that it is not in electrical contact with said first output node or said second output node in a state of the device, said nanotube channel element having a first operating voltage range; and

a control structure disposed in relation to the nanotube channel element to controllably form and unform an electrically conductive channel between said first output node and said second output node for transferring a signal between said first output node and said second output node, said channel including said nanotube channel element, said control structure including a control electrode having a second operating voltage range wherein an upper operating voltage of said second operating range exceeds an upper operating voltage of said first operating range by at least an amount sufficient to ensure channel formation.

2. The device of claim 1, wherein said nanotube channel element is constructed and arranged so that no electrical signal is provided to the nanotube channel element in a state of the device.

3. The device of claim 1, wherein said nanotube channel element has a floating potential in a state of the device.

4. The device of claim 1, wherein said control structure is arranged in relation to the nanotube channel element to form said conductive channel by causing electromechanical deflection of said nanotube channel element.

5. The device of claim 4, wherein the electromechanical deflection causes the nanotube channel element to electrically contact a first output electrode in said first output node and a second output electrode in said second output node.

6. The device of claim 1, wherein said first and second output nodes each include an isolation structure disposed in relation to the nanotube channel element so that channel formation is substantially regardless of the state of the output nodes.

7. The device of claim 6, wherein said isolation structure includes electrodes disposed on opposite sides of the nanotube channel element and said electrodes produce substantially equal but opposite electrostatic forces.

8. The device of claim 7, wherein electrodes of said first and second output nodes disposed on one side of said nanotube channel element are electrically insulated from said nanotube channel element by an insulator.

9. The device of claim 7, wherein said isolation structure includes electrodes disposed on opposite sides of the nanotube channel element that are in low resistance electrical communication with each other.

10. The device of claim 1, wherein said nanotube channel element is suspended between insulative supports in spaced-relation relative to a control electrode of the control structure and wherein deflection of said nanotube channel element is in response to electrostatic attractive forces resulting from signals on the control electrode, independent of signals on the first output node or the second output node.

11. The device of claim 1, wherein said nanotube channel element is constructed from nanofabric.

12. The device of claim 1, wherein said control electrode is electrically isolated from said nanotube channel element by an insulator.

13. The device of claim 1, wherein said nanotube channel element retains a positional state when a deflecting control signal provided via the control structure is removed.

14. The device of claim 1, wherein said nanotube channel element returns to a normal positional state when a deflecting control signal provided via the control structure is removed.

15. The device of claim 1, wherein each output node includes a pair of output electrodes in electrical communication, the output electrodes of each pair being disposed on opposite sides of the nanotube channel element.

16. The device of claim 1, the control structure including a second control electrode, the control electrode and second control electrode being disposed in relation to the nanotube channel element to control formation of the electrically conductive channel between the first output node and the second output node, the control electrode and the second control electrode being positioned on opposite sides of the nanotube channel element.

17. A transfer device circuit, comprising:

a nanotube transfer device, including a first node, a second node, a nanotube channel element including at least one electrically conductive nanotube, and a control structure disposed in relation to the nanotube channel element to controllably form and unform an electrically conductive channel between said first node and said second node, said channel including said nanotube channel element; and

a signal shaping circuit electrically coupled to said control structure, said signal shaping circuit receiving an input signal and providing a control signal representative of said input signal to the control structure, a value of said control signal inducing channel formation regardless of the potential of the nanotube switching element.

18. The circuit of claim 17, wherein said signal shaping circuit overdrives said control signal to a voltage above a supply voltage to predictably induce formation of the channel.

19. The circuit of claim 17, wherein a second value of said control signal ensures the absence of channel formation regardless of the potential of the nanotube switching element.

20. The circuit of claim 17, wherein said signal shaping circuit shifts said input signal from a first range to a second range to provide said control signal, wherein the state of channel formation is predictable at the endpoints of the second range.

21. The circuit of claim 17, wherein said control structure includes a first control electrode and a second control electrode disposed on opposite sides of the nanotube channel element, the control signal being provided to the first control electrode, further comprising a second signal shaping circuit electrically coupled to said control structure, said second signal shaping circuit receiving a second input signal and providing a second control signal representative of the second input signal to the second control electrode, a value of said second input signal inducing unforming of the channel regardless of the potential of the nanotube switching element.

22. The circuit of claim 17, wherein said nanotube channel element is not in direct electrical communication with either said first node or said second node in a state of the device.