Non-volatile electromechanical field effect devices and circuits using same and methods of forming same

• US 20050237781A1
• Filed: 10/18/2004
• Published: 10/27/2005
• Est. Priority Date: 06/09/2003
• Status: Active Grant

• Current Assignee: Nantero Incorporated
• Original Assignee: Nantero Incorporated
• Inventors: Bertin, Claude L., Rueckes, Thomas, Berg, John E.
• Granted Patent: US 7,274,064 B2
• Time in Patent Office: Days
• US Class Current: 365/145
• 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 11/412 using field-effect transistors only
• CPC Class Codes: G11C 11/54 using elements simulating biological cells, e.g. neuron
• CPC Class Codes: G11C 13/025 using fullerenes, e.g. C60, or nanotubes, e.g. carbon or silicon nanotubes
• CPC Class Codes: G11C 16/0416 comprising cells containing a single floating gate transistor and no select transistor, e.g. UV EPROM
• 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: G11C 8/10 Decoders
• 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 977/733 Nanodiaphragm

Abstract

Non-volatile field effect devices and circuits using same. A non-volatile field effect device includes a source, drain and gate with a field-modulatable channel between the source and drain. Each of the source, drain, and gate have a corresponding terminal. An electromechanically-deflectable, nanotube switching element is electrically positioned between one of the source, drain and gate and its corresponding terminal. The others of the source, drain and gate are directly connected to their corresponding terminals. The nanotube switching element is electromechanically-deflectable in response to electrical stimulation at two control terminals to create one of a non-volatile open and non-volatile closed electrical communication state between the one of the source, drain and gate and its corresponding terminal. Under one embodiment, one of the two control terminals has a dielectric surface for contact with the nanotube switching element when creating a non-volatile open state. Under one embodiment, the source, drain and gate may be stimulated at any voltage level from ground to supply voltage, and wherein the two control terminals are stimulated at any voltage level from ground to a switching threshold voltage larger in magnitude than the supply voltage. Under one embodiment, the nanotube switching element includes an article made from nanofabric that is positioned between the two control terminals. Under one embodiment, one of the two control terminals is a release electrode for electrostatically pulling the nanotube article out of contact with the one of the source, drain and gate so as to form a non-volatile open state. Under one embodiment, the other of the two control terminals is a set electrode for electrostatically pulling the nanotube article into contact with the one of the source, drain and gate so as to form a non-volatile closed state.

Claims

1. A non-volatile field effect device, comprising:

a lithographically-dimensioned source, drain, and gate with a field-modulatable channel between the source and drain, each of the source, drain, and gate having a corresponding terminal; and

a lithographically-dimensioned, electromechanically-deflectable, nanotube switching element that is coincident with an abutted edge of the gate such that it is in electrical and physical contact with the gate and its corresponding terminal, the others of said source and drain being directly connected to their corresponding terminals;

wherein the nanotube switching element is;

electromechanically-deflectable in response to electrical stimulation at two control terminals to create one of a non-volatile open and non-volatile closed electrical communication state between the one of the source, drain and gate and its corresponding terminal, wherein one of the control terminals is positioned over the gate; and

adjacent to and non-overlapping with the field-modulatable channel.

2. The device of claim 1, wherein the nanotube switching element includes an article formed of nanotube fabric.

3. The device of claim 2 wherein the nanotube fabric is a porous nanotube fabric.

4. The device of claim 1 wherein one of the two control terminals has a dielectric surface for contact with the nanotube switching element when creating a non-volatile open state.

5. The device of claim 1 wherein the source, drain and gate may be stimulated at any voltage level from ground to supply voltage, and wherein the two control terminals are stimulated at any voltage level from ground to a switching threshold voltage larger in magnitude than the supply voltage.

6. The device of claim 2 wherein the nanotubes are single-walled carbon nanotubes.

7. The device of claim 1 wherein modulation of the channel region includes inverting the conductivity type of the channel region.

8. The device of claim 1 wherein the fabric is substantially a monolayer of nanotubes.

9. The device of claim 1 wherein the nanotube switching element includes an article made from nanofabric that is positioned between the two control terminals.

10. The device of claim 9 wherein one of the two control terminals is a release electrode for electrostatically pulling the nanotube article out of contact with the one of the source, drain and gate so as to form a non-volatile open state.

11. The device of claim 10 wherein the other of the two control terminals is a set electrode for electrostatically pulling the nanotube article into contact with the one of the source, drain and gate so as to form a non-volatile closed state.

12. The device of claim 9 wherein the one of the source, drain and gate is a set electrode for electrostatically pulling the nanotube article into contact with the terminal corresponding to the one of the source, drain and gate so as to form a non-volatile closed state.

13. The device of claim 1 wherein the device has only four terminals to control its operation.

14. The device of claim 1 wherein, when the nanotube switching element is in a closed state, the channel conductivity and operation of the device is responsive to electrical stimulus at the terminals corresponding to the source, gate and drain.

15. The device of claim 1 wherein one of the two control terminals is operably in communication with the nanotube switching element to turn the device into an on mode and an off mode, such that in the on mode the device the source, drain, and gate may be used to module the channel and in the off mode the channel is non-conductive irrespective of source, drain, and gate stimulus.

16. The device of claim 1 wherein the device is a memory cell with information state non-volatilely stored by the position of the nanotube switching element.

17. The device of claim 15 wherein when the device is in the on mode the source signal is a digital inversion of the gate signal.

18. The device of claim 15 wherein when the device is in the on mode the source signal is an analog inversion of the gate signal.