124results about "Nanoelectromechanical switches" patented technology

Electrical devices comprised of nanoscopic wires are described, along with methods of their manufacture and use. The nanoscopic wires can be nanotubes, preferably single-walled carbon nanotubes. They can be arranged in crossbar arrays using chemically patterned surfaces for direction, via chemical vapor deposition. Chemical vapor deposition also can be used to form nanotubes in arrays in the presence of directing electric fields, optionally in combination with self-assembled monolayer patterns. Bistable devices are described.

Nanotube device structures and methods of fabrication. Under one embodiment, a method of forming a nanotube switching element includes forming a first structure having at least one output electrode, forming a conductive article having at least one nanotube, and forming a second structure having at least one output electrode and positioning said second structure in relation to the first structure and the conductive article such that the output electrode of the first structure is opposite the output electrode of the second structure and such that a portion of the conductive article is positioned therebetween. At least one signal electrode is provided in electrical communication with the conductive article having at least one nanotube, and at least one control electrode is provided in relation to the conductive article such that the conductive electrode may control the conductive article to form a channel between the sginal electrode and at least one of the output electrodes. The first and second structures each include a respective second output electrode and wherein the second electrodes are positioned opposite each other with the conductive article positioned therebetween. The control electrode and the second control electrode includes an insulator layer on a surface facing the conductive article.

Nanotube-based switching elements and logic circuits. Under one embodiment of the invention, a switching element includes an input node, an output node, a nanotube channel element having at least one electrically conductive nanotube, and a control electrode. The control electrode is disposed in relation to the nanotube channel element to controllably form an electrically conductive channel between the input node and the output node. The channel at least includes said nanotube channel element. The output node is constructed and arranged so that channel formation is substantially unaffected by the electrical state of the output node. Under another embodiment of the invention, the control electrode is arranged in relation to the nanotube channel element to form said conductive channel by causing electromechanical deflection of said nanotube channel element. Under another embodiment of the invention, the output node includes an isolation structure disposed in relation to the nanotube channel element so that channel formation is substantially invariant from the state of the output node. Under another embodiment of the invention, the isolation structure includes electrodes disposed on opposite sides of the nanotube channel element and said electrodes produce substantially the same electric field. Under another embodiment of the invention, a Boolean logic circuit includes at least one input terminal and an output terminal, and a network of nanotube switching elements electrically disposed between said at least one input terminal and said output terminal. The network of nanotube switching elements effectuates a Boolean function transformation of Boolean signals on said at least one input terminal. The Boolean function transformation includes a Boolean inversion within the function, such as a NOT or NOR function.

Nanotube ESD protective devices and corresponding nonvolatile and volatile nanotube switches. An electrostatic discharge (ESD) protection circuit for protecting a protected circuit is coupled to an input pad. The ESD circuit includes a nanotube switch electrically having a control. The switch is coupled to the protected circuit and to a discharge path. The nanotube switch is controllable, in response to electrical stimulation of the control, between a de-activated state and an activated state. The activated state creates a current path so that a signal on the input pad flows to the discharge path to cause the signal at the input pad to remain within a predefined operable range for the protected circuit. The nanotube switch, the input pad, and the protected circuit may be on a semiconductor chip. The nanotube switch may be on a chip carrier. The deactivated and activated states may be volatile or non-volatile depending on the embodiment. The ESD circuit may be repeatedly programmed between the activated and deactivated states so as to repeatedly activate and deactivate ESD protection of the protected circuit. The nanotube switch provides protection based on the magnitude of the signal on the input pad.

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 electromechanical 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.

Uses of electromechanical nanoswitches made from preformed carbon nanotube films, layers, fabrics, ribbons, are disclosed.

Field effect devices having a drain controlled via a nanotube switching element. Under one embodiment, a field effect device includes a source region and a drain region of a first semiconductor type and a channel region disposed therebetween of a second semiconductor type. The source region is connected to a corresponding terminal. A gate structure is disposed over the channel region and connected to a corresponding terminal. A nanotube switching element is responsive to a first control terminal and a second control terminal and is electrically positioned in series between the drain region and a terminal corresponding to the drain region. The nanotube switching element is electromechanically operable to one of an open and closed state to thereby open or close an electrical communication path between the drain region and its corresponding terminal. When the nanotube switching element is in the closed state, the channel conductivity and operation of the device is responsive to electrical stimulus at the terminals corresponding to the source and drain regions and the gate structure.

Nanotube-based switching elements with multiple controls and circuits made from such. A switching element includes an input node, an output node, and a nanotube channel element having at least one electrically conductive nanotube. A control structure is disposed in relation to the nanotube channel element to controllably form and unform an electrically conductive channel between said input node and said output node. The output node is constructed and arranged so that channel formation is substantially unaffected by the electrical state of the output node. The control structure includes a control electrode and a release electrode, disposed on opposite sides of the nanotube channel element. The control and release may be used to form a differential input, or if the device is constructed appropriately to operate the circuit in a non-volatile manner. The switching elements may be arranged into logic circuits and latches having differential inputs and/or non-volatile behavior depending on the construction.

Hybrid switching devices integrate nanotube switching elements with field effect devices, such as NFETs and PFETs. A switching device forms and unforms a conductive channel from the signal input to the output subject to the relative state of the control input. In embodiments of the invention, the conductive channel includes a nanotube channel element and a field modulatable semiconductor channel element. The switching device may include a nanotube switching element and a field effect device electrically disposed in series. According to one aspect of the invention, an integrated switching device is a four-terminal device with a signal input terminal, a control input terminal, a second input terminal, and an output terminal. The devices may be non-volatile. The devices can form the basis for a hybrid NT-FET logic family and can be used to implement any Boolean logic circuit.

Circuit arrays having cells with combinations of transistors and nanotube switches. Under one embodiment, a circuit array includes a plurality of cells arranged in an organization of words, each word having a plurality of bits. Each cell is responsive to a bit line, word line, reference line, and release line. Bit lines are arranged orthogonally relative to word lines and each word line and bit line are shared among a plurality of cells. Each cell is selectable via the activation of the bit line and word line. Each cell includes a field effect transistor coupled to a nanotube switching element. The nanotube switching element is switchable to at least two physical positions at least in part in response to electrical stimulation via the reference line and release line. Information state of the cell is non-volatilely stored via the respective physical position of the nanotube switching element. Under another embodiment, a circuit array includes a plurality of cells arranged in an organization of words, each word having a plurality of bits. Each cell is responsive to a bit line, word line, and reference line. Each word line and bit line are shared among a plurality of cells. Each cell is selectable via the activation of the bit line and word line. Each cell includes a field effect transistor and a nanotube switching element. Each nanotube switching element includes a nanotube article positioned between a set electrode and a release electrode. The set electrode may be electrically stimulated to electro-statically attract the nanotube article into contact with the set electrode and the release electrode may be electrically stimulated to electro-statically attract the nanotube article out of contact with the set electrode. Information state of the cell is non-volatilely stored via the respective physical position of the nanotube switching element. Cells are arranged as pairs with the nanotube switching elements of the pair being cross coupled so that the set electrode of one nanotube switching element is coupled to the release electrode of the other and the release electrode of the one nanotube switching element being coupled to the set electrode of the other. The nanotube articles are coupled to the reference line, and the source of one field effect transistor of a pair is coupled to the set electrode to one of the two nanotube switching elements and the source of the other field effect transistor of the pair is coupled to the release electrode to the one of the two nanotube switching elements.

Nano-electromechanical device having an electrically conductive nano-cantilever wherein the nano-cantilever has a free end that is movable relative to an electrically conductive substrate such as an electrode of a circuit. The circuit includes a power source connected to the electrode and to the nano-cantilever for providing a pull-in or pull-out voltage therebetween to effect bending movement of the nano-cantilever relative to the electrode. Feedback control is provided for varying the voltage between the electrode and the nano-cantilever in response to the position of the cantilever relative to the electrode. The device provides two stable positions of the nano-cantilever and a hysteresis loop in the current-voltage space between the pull-in voltage and the pull-out voltage. A first stable position of the nano-cantilever is provided at sub-nanometer gap between the free end of the nano-cantilever and the electrode with a pull-in voltage applied and with a stable tunneling electrical current present in the circuit. A second stable position of the nano-cantilever is provided with a pull-out voltage between the cantilever and the electrode with little or no tunneling electrical current present in the circuit. The nano-electromechanical device can be used in a scanning probe microscope, ultrasonic wave detection sensor, NEMS switch, random access memory element, gap sensor, logic device, and a bio-sensor when the nano-cantilever is functionalized with biomolecules that interact with species present in the ambient environment be them in air or aqueous solutions. In the latest case, the NEMS needs to be integrated with a microfluidic system.

Nanotube-based logic circuitry is disclosed. Tri-stating elements add an enable/disable function to the circuitry. The tri-stating elements may be provided by nanotube-based switching devices. In the disabled state, the outputs present a high impedance, i.e., are tri-stated, which state allows interconnection to a common bus or other shared communication lines. In embodiments wherein the components are non-volatile, the inverter state and the control state are maintained in the absence of power. Such an inverter may be used in conjunction with and in the absence of diodes, resistors and transistors or as part of or as a replacement to CMOS, biCMOS, bipolar and other transistor level technologies.

Switches having an in situ grown carbon nanotube as an element thereof, and methods of fabricating such switches. A carbon nanotube is grown in situ in mechanical connection with a conductive substrate, such as a heavily doped silicon wafer or an SOI wafer. The carbon nanotube is electrically connected at one location to a terminal. At another location of the carbon nanotube there is situated a pull electrode that can be used to electrostatically displace the carbon nanotube so that it selectively makes contact with either the pull electrode or with a contact electrode. Connection to the pull electrode is sufficient to operate the device as a simple switch, while connection to a contact electrode is useful to operate the device in a manner analogous to a relay. In various embodiments, the devices disclosed are useful as at least switches for various signals, multi-state memory, computational devices, and multiplexers.

A switch element includes a substrate; a plurality of carbon nanotubes provided upright on the substrate; magnetic particles arranged at tip ends of the carbon nanotubes respectively; and a plurality of conductive layers formed between base ends of the carbon nanotubes and the substrate. A switching operation of the switching element is performed in such a manner that the carbon nanotubes or the magnetic particles are brought into contact with each other according to an electrical potential between the conductive layers, and the carbon nanotubes are separated from each other when an electrical current flows through the carbon nanotubes with the carbon nanotubes or the magnetic particles brought into contact with each other.

Methods of producing an electromechanical circuit element are described. A lower structure having lower support structures and a lower electrically conductive element is provided. A nanotube ribbon (or other electromechanically responsive element) is formed on an upper surface of the lower structure so as to contact the lower support structures. An upper structure is provided over the nanotube ribbon. The upper structure includes upper support structures and an upper electrically conductive element. In some arrangements, the upper and lower electrically conductive elements are in vertical alignment, but in some arrangements they are not.