Non-volatile electromechanical field effect devices and circuits using same and methods of forming same
View Patent ↗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.
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, wherein the source and drain are directly connected to their corresponding terminals; 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,
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 gate and its corresponding terminal, wherein one of the control terminals is positioned over the gate; and
wherein the nanotube switching element is offset from 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 nanotube fabric comprises 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 2 wherein the nanotube fabric comprises 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 terminal corresponding to the 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 terminal corresponding to the gate so as to form a non-volatile closed state.
12. The device of claim 1 wherein the device has only four terminals to control its operation.
13. 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.
14. 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 modulate the channel and in the off mode the channel is non-conductive irrespective of source, drain, and gate stimulus.
15. 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.
16. The device of claim 14 wherein when the device is in the on mode the source signal is a digital inversion of the gate signal.
17. The device of claim 14 wherein when the device is in the on mode the source signal is an analog inversion of the gate signal.