Wednesday, June 20, 2007

US Patent 7233517 - Coated atomic force probe for data storage

A variety of companies are working on implementing high density memories approaching Terabit/in^2 using scanning probe technologies that were originally designed as microscopes for the atomic and molecular scale in the 1980's. This patent is from a company called Nanochip and provides some fairly broad claims drawn to the use of a coated atomic tip for such data storage. For example claim 2 reads:

2. An atomic probe for high density data storage reading, writing, erasing, or rewriting, comprising: a core coupled with a coating; and wherein the coating contacts a media device.

Unfortunately, the Examiner may have overlooked references such as

which teaches metal coated AFMs.

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US Patent 7233101 - Steerable nanowire E-beams

Electron emitting nanomaterials such as carbon nanotubes and nanocrystalline diamond are finding many applications in flat panel displays, x-ray sources, microwave amplifiers, and E-beam lithography. Some of the key advantages of using nanomaterials for electron emission are:

a) there is a low threshold voltage necessary for the emission which can lead to more energy efficient products (example: cell phones using field emission based displays would require less frequent charging)

b) these materials are gradually being integrated with semiconductor processing methods and circuits which can ultimately reduce cost and size of any products using E-beams for their operation (example: handheld electron microscopes)

c) high density arrays of electron emitters are able to be formed from nanostructures allowing for parallel processing which can make certain applications operate more quickly (example: E-beam lithography, which is primarily limited due to the serial nature of scanning the E-beam, can be tremendously enhanced by the use of closely spaced carbon nanotube emitters working in parallel)

This patent from Samsung is directed to the individual positioning control of parallel arrays of nanowire field emitters. Claim 1 reads:

1. A substrate-supported array of spaced-apart nanowires comprising: a substrate; and disposed upon the substrate a plurality of spaced-apart, aligned and individually steerable nanowires having a ratio of a nanowire spacing to a nanowire height of at least 0.2 and a nanowire diameter in the a range of 1 500 nanometers, wherein the nanowire height is in a range of 0.1 to 200 micrometers, and a ratio of the nanowire height to the nanowire diameter is between approximately 4,500 and 10,000.

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Tuesday, June 19, 2007

US Patent 7233041 - Complementary nanowire inverter

This patent to Nanosys claims a structure analogous to a CMOS inverter but formed using aligned arrays of nanowires. Claim 1 reads:

1. An article comprising: at least a first and a second population of semiconducting nanowires disposed at distinct, non-overlapping regions from each other on a surface of a substrate, wherein nanowires in the first and second population each comprise a core and one or more shell layers disposed about said core; at least a first and a second pair of spaced-apart electrical contacts disposed at the distinct regions on the surface of the substrate, wherein at least two nanowires in each of the respective first and second populations of nanowires span and are electrically connected to the electrical contacts of each of the respective first and second pair of electrical contacts; and wherein nanowires in each of the first and second population of nanowires are substantially oriented in a first direction on the surface of the substrate.

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US Patent 7232771 - Flexible electrostatic nanoimprint stamp

This patent is directed to a new type of nanoimprint lithography employing electrostatic charging to transfer nanoparticle patterns onto a substrate. Although it is not the first patent to use electrostatic transfer in an imprint lithography system (see US Patent 7223444) it adds the feature of a flexible substrate as the stamp structure. Claim 1 reads:

1. A method of depositing nanoparticles on a substrate, comprising: obtaining a flexible stamp having a pattern formed thereon, the flexible stamp including a flexible overlayer of semiconductor material forming the pattern; applying the flexible stamp to the substrate to form a charge pattern on the substrate; and depositing nanoparticles on the charged pattern on the substrate.


Friday, June 15, 2007

Nanomaterials and Morphware

The latest issue of the Nanotechnology Law and Business Journal (vol. 4.2) includes an article I wrote about the effects of nanomaterials on "Morphware" which is a term used to describe reconfigurable circuit architectures such as FPGAs. Based on patenting trends there is a definite drive toward reconfigurability as a way to augment performance as further scaling reduction becomes more difficult and costly.

While the paradigm in electronics for the past 40 years has been driven by Moore’s law, making smaller circuits is not the only way to increase the functionality and performance of electronics devices. Reconfigurable hardware, otherwise known as “morphware,” offers the possibility of providing more function with fewer circuit components when size reduction of circuit features becomes cost prohibitive. Nanostructured and molecular materials have begun to be applied to morphware allowing for electronic hardware with the flexibility and programmability of software. This article looks beyond the advantages of nanomaterials in shrinking circuit size toward applications of nanomaterials in which the impact of morphware is dominant.

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Thursday, June 14, 2007

US Patent 7230432 - Nanotube sensor with heat controlled gas removal

This patent from Honeywell teaches the use of a fairly clever construction for reusing nanotube gas sensors using heat controlled removal of gas after sensing. Claim 1 reads:

1. A method for sensing a gas/liquid, comprising: obtaining a structure having first and second terminals connected to the ends of a nanotube, respectively; exposing the nanotube to a gas/liquid; measuring a current-voltage characteristic of the nanotube; reviewing the current-voltage characteristic to obtain possible information about the gas/liquid; and heating the nanotube to desorb the gas/liquid from the nanotube.

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US Patent 7230306 - Integrated cantilever/transistor for MEMS

IMEMS is an acronym often used referring to integrated microelectromechanical systems and refers to devices in which both micromechanical structures and the electronics used to control the micromechanical structures are formed on the same substrate. This is often easier said then done since very different process steps and materials may be involved in the fabricating of the control circuit versus the fabrication of the micromechanical component. This patent teaches one method of integration in which a transistor is formed within a microcantilever by using different crystalline structures. Claim 1 reads:

1. A microelectromechanical system (MEMS) thin-film device comprising: a mechanical device having a mechanical body made from a thin-film material; an electronic device formed within the mechanical body; wherein the mechanical device is a cantilever beam, including a thin-film material with a first crystalline structure; and, wherein the electrical device is a transistor, including a semiconductor material having a second crystalline structure.


Wednesday, June 13, 2007

US Patent 7230286 - Silicided bottom contact for nanowire FET

In vertical FETs the current flows through a vertical channel extending from a substrate in a direction perpendicular to the plane of the substrate. However, when nanowires are used for the vertical channels the contact resistance can be too high. This patent from IBM teaches using a silicide (i.e. metal-silicon compound) to reduce the contact resistance. Claim 1 reads:

1. A semiconductor structure comprising: a silicide contact layer located within, or on a portion of a semiconductor substrate; a plurality of nanowires located on said silicide contact layer; a gate dielectric surrounding said plurality of nanowires; a gate conductor located on said gate dielectric; and a source and drain located at each end of said nanowires.

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US Patent 7230266 - Oscillation readout for quantum computing

D-Wave is a company that focuses on superconducting electronics to achieve quantum computing and currently has the largest U.S. patent portfolio in this area. Although superconducting materials can be difficult to work with if the development of a quantum computer is achieved it will open up the possibility of more exact modeling and simulation of stochastic phenomena which can be applied to economic and weather forecasting. This latest patent focuses on a reading method of a qubit using the frequency response of a quantum system. Claim 1 reads:

1. A method for determining whether a first state of a quantum system is occupied, the method comprising: (A) applying a signal to the quantum system at a frequency that corresponds to an energy level separation between said first state and a second state of said quantum system, wherein (i) said quantum system produces a readout frequency when said first state is occupied at a time when said signal is applied, and (ii) said quantum system does not produce said readout frequency when said first state is not occupied at the time when said signal is applied; and (B) measuring a property of a measurement resonator that is conditionally coupled to the quantum system when said quantum system produces said readout frequency, thereby determining whether said first state of said quantum system is occupied.

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Tuesday, June 12, 2007

US Patent 7229944 - Carbon fiber sheet

Catalytic membranes are a component of fuel cells that can help speed up reactions and improve efficiency. This patent from M.I.T. discloses catalytic membranes formed using carbon nanofibers. Claim 1 reads:

1. A structure comprising: a carbon fiber sheet-like structure having a thickness of less than 10 microns and including at least one carbon fiber having a length of greater than about 500 microns; and a catalytic material supported on the carbon fiber sheet-like structure, wherein carbon fiber of the structure has an average diameter of less than about 500 nanometers.

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US Patent 7229847 - Electrode-molecule interconnects using imprint stamp

A variety of techniques have been used to form interconnects between molecular structures and electrodes but many of these techniques result in shorts that can decrease the effectiveness of a molecular junction. This patent from Lucent teaches use of an imprint stamp to form electrodes for molecular interconnects to help alleviate shorting defects caused when an opposing electrode is deposited. Claim 1 reads:

1. A process for forming electrical contacts to a molecular layer comprising: coating raised and relief portions of a surface of a stamp with a metal layer; foaming an attached layer of anchored molecules by covalently bonding first ends of said anchored molecules to one of either a conductive or semiconductive substrate or said metal layer; and placing the other of said conductive or semiconductive substrate or said metal layer in contact with said attached layer of anchored molecules, said conductive or semiconductive substrate or said metal layer covalently bonding to free ends of said anchored molecules.


Monday, June 11, 2007

US Patent 7228094 - Nanopowder on substrate

Yipes! This patent claim from Xerox is directed to a donor used in electrophotography processes but some of the claims appear quite broad.

1. A donor member comprising a substrate and having thereover a coating comprising a nano-size powder having a particle size of from about 25 to about 500 nanometers.

Although the specification of "donor member" may limit the breadth somewhat, many publications to metallic, magnetic, carbon-based, or other nanoparticle films formed on a substrate that would be in the cited range can be found by doing a quick survey of GoogleScholar prior to the priority date of this patent. See for example:

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US Patent 7228050 - Inorganic nanowires with orienting matrix

While high aspect ratio nanostructures (aka nanowires) can have favorable properties individually, when combined in a binding matrix these properties can be lost due to the disordered distribution of the nanowires or lack of cohesiveness between the nanowires. This patent from Nanosys teaches using a polymer or small molecule matrix to facilitate alignment of inorganic nanowires with a core/shell structure. Claim 1 reads:

1. A composite material, comprising: a plurality of discrete, preformed inorganic nanowires, wherein the inorganic nanowires comprise a core and one or more shell layers disposed about the core; and a small molecule or molecular matrix or a matrix comprising at least one polymer, which small molecule or molecular matrix or components thereof or which matrix comprising at least one polymer or components thereof are used to orient the nanowires.

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Friday, June 08, 2007

Thursday, June 07, 2007

US Patents 7227379 and 7228518 - Nanowire crossbar arrays

Of all of the different approaches to nanoelectronic architectures I've come across the approach taken by Hewlett Packard (nanowire crossbar arrays) seems the most likely to have a substantial impact in the next 5-10 years. Some of the advantages of HPs approach are as follows:

1) Many of the proposed implementations of nanowire crossbars complement rather than attempt to replace more conventional electronics. Hybrid systems based on HP's nanowire crossbars such as CMOL (combining CMOS and molecular electronics) are in the works. This can facilitate a less disruptive, and thus more easily acceptable, electronics platform on which molecular based electronics may flourish.

2) The manufacturing of these devices are fairly cost effective since they are based on regular, periodic structures and complex patterning is not necessary. HP has advanced technologies such as nanoimprint lithography which provide for cheaper avenues of fabrication than the traditional EUV lithography and the capability of process scaling for mass production. HP is also supporting or working with other smaller companies to promote the use of nanoimprint lithography.

3) HP is creating a learning base based on applications in high-density resistive memory which may be applied to niche applications controlled by HP such as the non-volatile memorys used in inkjet print cartridges. The lessons learned in nanowire crossbar memory devices will undoubtably pay off as applications in nanowire crossbar processors come into fruition.

4) The nanowire crossbar architectures presents new capabilities beyond what is offered by silicon by providing the ability to form electronics on flexible (e.g. plastic) substrates and by allowing for reconfigurability (allowing for circuit self-repair and ease of integration with adaptive electronic systems such as FPGAs).

These are two of the most recent patents and representative claims from HP on this technology-one dealing with the creation of 1 bit register arrays and the other on how multilevel nanowire crossbar arrays may be formed by folding the substrate on which the nanowires are placed.

1. A nanoscale computing engine comprising: a nanowire data bus; a plurality of nanoscale registers interconnected by the nanowire data bus, each nanoscale register driven by a nanoscale control line; and primitive operations, each primitive operation composed of one or more inputs to one or more of the nanowire data bus and nanoscale control lines, that provide for transfer of information from an external source to a specified nanoscale register, transfer of information from a nanoscale register source to an external target, and transfer of information from a first nanoscale register to a second nanoscale register.

1. A method for obtaining a multilayer nanowire-crossbar design that is functionally equivalent to a two-layer nanowire crossbars design, the method comprising: receiving the two-layer nanowire-crossbar design having two or more microregions; folding the two-layer nanowire-crossbar design between the two or more microregions; and collapsing folded nanowires into single nanowires, which yields the multilayer nanowire-crossbar design.

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Wednesday, June 06, 2007

US Patent 7227177 - Room temperature quantum confinement in nanocrystal

Doping of nanostructured materials is important if they are ever to be used to form diode, transistor, or various other electronic structures based on semiconductor physics. This patent is from a company called Arch Development (which appears to be some type of venture capital fund based on Google searching) and presents some seemingly very broad claims to semiconductor nanocrystals (aka quantum dots) used in photovoltaics. Apparently, based on the specification, the inventors teach using electrons instead of n-type dopant atoms (P, As, Sb)to dope quantum dots and allege that quantum dots of the prior art only include electrons in a trapped state rather than in a "quantum confined state at room temperature" as claimed. Claim 1 reads:

1. A photovoltaic device, comprising: a semiconductor nanocrystal for the photovoltaic device, wherein said nanocrystal is doped with an electron, such that the electron is in a quantum confined state at room temperature and in the absence of an applied electric potential.

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US Patent 7227173 - LED with quantum dot/quantum well coupling

Quantum wells are thin films that create a two-dimensional barrier structure that confine electrons and are useful in a variety of applications including lasers and photodetectors. Quantum dots are structures which further confine electrons into zero dimensions. While quantum well based optoelectronic devices are fairly well established, there is a desire to use quantum dots to improve efficiency. However, it is difficult to achieve the necessary uniformity of size and sufficient distribution density to use quantum dot layers effectively. This patent proposes using adjacent quantum wells to create a bridge to facilitate the electron transfer between quantum dots. Claim 2 is representative.

2. A semiconductor device, comprising: a plurality of semiconductor layers; means for coupling signals to and/or from semiconductor layers of said semiconductor device; and a layer of doped quantum dots, comprised of III-V semiconductor material, disposed in at least one of said semiconductor layers as a source of carriers that communicate in either direction between said doped quantum dots and another layer.


Tuesday, June 05, 2007

US Patent 7227140 - Focused ion beam nanomanipulator

Zyvex is a company pursuing new approaches to manipulating matter on the nanoscale. While atomic force microscopy and nanotweezers have been used for molecular positioning they are hampered by electrostatic forces that can make it difficult to separate the molecular structures being manipulated for the tool performing the manipulation. This patent teaches a combination of a focused ion beam cutting tool and grasping elements (e.g. MEMS actuators) to regulate the positioning of samples for inspection by electron microscopy. Claim 1 reads:

1. A system, comprising: focused ion beam (FIB) means for at least partially severing a sample from a substrate; a grasping element configured to mechanically capture the sample; means for mechanically activating the grasping element to mechanically capture the sample; and means for separating the captured sample from the substrate.


US Patent 7226953 - Alkoxysilane-terminated nanocrystal sol-gel composites

One of the key difficulties in applying semiconductor nanocrystals in materials is coupling nanocrystals to a composite matrix. This patent teaches mixing colloidal nanocrystals with a sol-gel precursor to facilitate the forming of composites. Claim 1 reads:

1. A solid composite comprising the reaction product of (i) colloidal nanocrystals including at least a portion of alkoxysilane-terminated groups thereon and (ii) a sol-gel precursor material.