US Patent 8203171 - Defective graphene "memristor"

http://www.freepatentsonline.com/8203171.html

Despite the fact that Chua's memristor theory is an incorrect model for ReRAM switching processes HP continues to use the term in their patents to make the term generic. This latest patent of HP teaches a graphene variation of ReRAM. Another variation of graphene ReRAM was patented by SanDisk 3D (US 8048074). It will be interesting to see whether HP's incorrect use of the memristor term will introduce any 35 USC 112 enablement issues if their patents are litigated. Claim 1 of this HP patent reads:

1. A defective graphene-based memristor, comprising:

a first electrode;

a defective graphene structure adjacent the first electrode, the defective graphene structure comprising a defective graphene layer having one or more engineered defects, wherein an engineered defect comprises a nanopore;

a memristive material adjacent the defective graphene structure, the memristive material comprising a plurality of ions;

a second electrode adjacent the memristive material; and

a voltage source that generates an electric field between the first and the second electrodes, wherein the plurality of ions in the memristive material, under the influence of the electric field, form an ion conducting channel between the second electrode and the defective graphene structure.                             

US Patent 8188494 - White LED with nanowire light conversion

http://www.freepatentsonline.com/8188494.html

This patent from HP teaches forming a white light LED using a single UV or blue LED and nanoparticle material to convert the blue light to light including green and red wavelengths. Claim 1 reads:

1. An apparatus comprising:

a light emitting diode that is for outputting light comprising a blue wavelength;

a nanowire or nanoparticle coupled to a surface of said light emitting diode;

a second nanowire or nanoparticle coupled to said surface of said light emitting diode, wherein said nanowire is doped differently than said second nanowire; and

an electrode coupled to said light emitting diode, wherein said nanowire or nanoparticle is for receiving and converting said light into red and green light that is output from said nanowire or nanoparticle.                             

US Patent 8178842 - Nanowire bolometer photodetector

http://www.freepatentsonline.com/8178842.html

Bolometers are used in night vision sensors to convert infrared into visible light but are often limited to a narrow band of wavelengths that can be detected. This patent from HP teaches increasing the bandwidth of wavelengths that can be detected by using semiconductor nanowires. Claim 1 reads:

1. A photodetector comprising at least one bolometer nanowire disposed at least partially within a photon trap, wherein said nanowire comprises a blackened surface configured to absorb from far-infrared to visible light.

US Patent 8148800 - Semiconductor nanowire with removal of residual carriers

http://www.freepatentsonline.com/8148800.html

A switching speed of semiconductor nanowire-based devices may be limited by the presence of residual carriers that remain in or near the semiconductor junction when the device is turned off. This patent from HP teaches providing a carrier sink to improve the speed of switching for optical detectors or modulators based on semiconductor nanowires. Claim 1 reads:

1. A nanowire-based-device comprising:

a semiconductor nanowire having a semiconductor junction; and

a residual carrier sink, the residual carrier sink being adjacent to a surface of the nanowire proximal to the semiconductor junction,

wherein the residual carrier sink facilitates removal of residual carriers from the semiconductor junction using one or both enhanced recombination and direct extraction of residual carriers,

the nanowire-based device being one of an optical detector and an optical modulator.

US Patent 8120071 - Ionic mem-transistor

http://www.freepatentsonline.com/8120071.html

This patent from HP applies Leon Chua's concept of memristive systems in the development of a new type of field effect transistor. Some earlier concepts related to memtransistors (i.e. memory transistors) were discussed by Bernard Widrow in the 1960's in terms of a memistor and in a presentation I gave in an IEEE meeting back in 2010 (B.Mouttet, "Memristive systems analysis of 3-terminal devices," ICECS 2010, link). Claim 1 reads:

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

a source;

a drain;

a channel-formation portion disposed between and coupled with said source and said drain; and

a memristive gate disposed over said channel-formation portion and coupled with said channel-formation portion;

wherein said memristive gate comprises a plurality of mobile ions and a confinement structure for said plurality of mobile ions; and

said memristive gate is configured to switch said channel-formation portion from a first conductivity state to a second conductivity state in response to migration of said plurality of mobile ions within said confinement structure.

Memistors, Memristors, and Memresistors

I recently posted an updated historical review of memory resistors available at this link which may be of interest in relation to ReRAM non-volatile memory and neuromorphic technology.

Abstract

 In 2008 researchers at Hewlett-Packard announced the physical realization of the “memristor” which was theoretically predicted as a fundamental non-linear circuit element by Leon Chua in 1971. Since that time there have been numerous scientific papers applying the concept of memory resistors to a wide range of thin film materials used for a new type of non-volatile memory called ReRAM (resistive random-access memory). It has also been noted that memory resistors may be applicable to explain behavior of biological neurons and some research groups have developed circuit designs exploiting memory resistors as components of neuromorphic electronics. This article reviews the historical background of various forms of memory resistors including the Widrow-Hoff memistor, Chua’s memristor model, and a mem-resistor model I developed to correct some of the deficiencies in HP’s memristor model. The potential future of memory resistors with respect to artificial intelligence and robotics is briefly discussed.

US Patent 8043687 - Graphene layer growth

http://www.freepatentsonline.com/8043687.html

This patent from HP may provide a step forward for the mass production of graphene films useful for the development of higher speed nanoelectronics. Claim 1 reads:

1. A method for forming a graphene layer, the method comprising:

establishing an insulating layer on a substrate such that at least one seed region is formed therein, the insulating layer including a first surface that faces the substrate and a second surface opposed to the first surface that faces away from the substrate; and

exposing a seed material in the at least one seed region to a carbon-containing precursor gas, thereby initiating nucleation of the graphene layer on the seed material and enabling lateral growth of the graphene layer along at least a portion of the second surface of the insulating layer.

More evidence HP's "memristor" is fraud

"Bait-and-switch" scams are famously employed by used car salesman who advertise quality cars but sell lemons once customers take the bait. The "memristor" that HP has been claiming for the past few years is a scientific example of such a bait-and-switch scam. Originally HP claimed that thin films of TiO2 had the same properties of the memristor which was predicted by Leon Chua as a new 4th fundamental circuit element several decades ago. The problem is that the TiO2 materials do not obey the original definition of the memristor which requires a relationship between charge and magnetic flux linkage. However, HP and Chua have encouraged others (including myself, link) to incorrectly use the term memristor to enhance their reputation without regard to the scientific merits of their claim.

Recently at least a few scientists have begun to point out the illegitimacy of one of the paper's published by the HPLabs group. In the October 2011 issue of Applied Physics A: Material Science and Processing incorrect statements made by the researchers at HPLabs which are being foolishly circulated by other naive scientists was brought to light (link). Additional facts pointing to the memristor fraud conducted by HPLabs and Leon Chua include:

1) HP's memristor patents are junk. Both Samsung (US 7417271) and Sharp (US 7796416) own the main patents covering the memory resistance effects of TiO2 that HP has taken credit for. HP's related patents are mostly focused on molecular memory and nanowire crossbars (for a more detailed analysis see this link).

2) The discovery of TiO2 memory resistance effects dates back to the 1960's (link) and Bernard Widrow originally defined "memistor" to describe memory resistance effects for simulating neurons back in 1960 (link). It was only due to Leon Chua's ignorance of research in material science and neural models of Bernard Widrow that he considered his memristor an original idea. The researchers at HPLabs fail to correct this even though it has been pointed out to them repeatedly (by myself and others). 

More bad news for HP's "memristor" prospects

This week has been particularly bleak with respect to the future of the Hewlett-Packard company including a plunge in the stock price to new lows, the failure of HP's smartphone and tablet products, and the apparent desire of HP management to sell off their PC business entirely (link). It will be interesting to see what effect this has on HP's plan to market the "memristor" (i.e. memory resistor) in collaboration with Hynix as a form of RRAM (i.e. resistance RAM).

As I pointed out in an earlier blog entry it is readily apparent to anyone who actually bothers to study the patents related to memory resistors that HP is actually a latecomer to RRAM technology with practically no credible patents of value. In fact, Samsung (US 7417271) and Sharp (US 7796416) both have patents which HP would have to license to practice the TiO2 version of memory resistors for which HP's researchers took credit. It seems to me that even though HP has been very successful at taking credit for memory resistor technology from legitimate companies and innovators it appears increasingly unlikely that HP will be in a position to market the technology.

A detailed analysis of memory resistor patents, companies, and potential applications is available at this link.

US Patent 7972426 - Nanomaterial security mark

http://www.freepatentsonline.com/7972426.html

This patent from HP teaches nanomaterial based inks used as authentication marks on checks, documents, or other media. Some relevant prior art not considered during the examination of this patent is US Patent 6,617,583 from M.I.T. and US Patent 7,917,298 (priority 2003) from Nanosys. Claim 1 reads:

1. An ink including light-activated components utilized for printing a security mark, comprising:

a first ink component that defines a first spectral property, the first component being chosen from a nanocrystal, a quantum dot, and a carbon nanotube;

a second ink component that defines a second spectral property different from said first spectral property, the second component being chosen from a nanocrystal, a quantum dot, and a carbon nanotube; and

a solvent in which said first and second ink components are dispersed;

wherein the first and second spectral properties are each a wavelength specific feature chosen from the group consisting of an absorptive feature and a Raman feature.

US Patent 7960653 - Conductive nanowires for electrical interconnect

http://www.freepatentsonline.com/7960653.html

When integrating several different types of components (e.g. CMOS, MEMS, electro-optics) on a single semiconductor chip one problem is to create reliable electrical interconnects that are compatible with different thermal, mechanical, and electrical characteristics of each type of component. This patent from HP teaches a solution based on nanowire interconnects. Claim 1 reads:

1. An electrical interconnect, comprising:

first and second electrical contacts to be electrically connected, each electrical contact comprising a plurality of electrically conductive nanowires extending outwardly from a respective electrical contact; and

said nanowires of said first electrical contact configured to contact with said nanowires of said second electrical contact such that an electrical connection is established between said first electrical contact and said second electrical contact;

wherein said nanowires of said first and second electrical contacts comprise different materials such that contact between nanowires of said first and second electrical contacts is contact between two different materials.

US Patent 7924413 - Nanowire array resonator

http://www.freepatentsonline.com/7924413.html

This patent from HP teaches a way to fabricate light sensors and modulators with nanoscale dimensions based on semiconductor nanowires. Claim 1 reads:

1. A nanowire-based device comprising:

a reflective member;

a resonant cavity at least partially enclosed by the reflective member; and

at least one nanowire disposed within the resonant cavity, the nanowire including at least one active segment selectively disposed along the length of the nanowire to substantially coincide with antinodes of light to resonate within the cavity, the active segment to interact with the light to resonate within the cavity.

US Patent 7910915 - Light emitting nanowires in a resonant cavity

http://www.freepatentsonline.com/7910915.html

This patent from HP includes some basic claims to light emitting semiconductor nanowires grown in a resonant cavity. Claim 1 reads:

1. A device comprising:

a resonant cavity configured to resonate at least one wavelength of electromagnetic radiation within a range extending from about 300 nanometers to about 2,000 nanometers; and

a nanowire disposed within the resonant cavity, the nanowire comprising an active longitudinal segment comprising an active material, the active longitudinal segment being selectively disposed at a predetermined location within the resonant cavity, the active material being capable of emitting electromagnetic radiation at the at least one wavelength.

US Patent 7880318 - Passivated nanowire sensor

http://www.freepatentsonline.com/7880318.html

This patent from HP focuses on improving the stability of nanosensors by using a passivation layer. Claim 1 reads:

1. A sensing system, comprising:

a nanowire;

a passivation layer established on at least a portion of the nanowire;

a barrier layer established on the passivation layer;

a functionalized nanoparticle attached to an end of the nanowire; and

a functionalized coating established on the barrier layer.

US Patent 7875884 - Nanostructured hetro-crystalline thin film

http://www.freepatentsonline.com/7875884.html

Polycrystalline thin film semiconductors may be used to fabricate solar cells and thin film transistors at low cost but introduce increased electron/hole scattering in comparison to single crystal semiconductors. This patent from HP focuses on combining the benefits of single crystalline material with the low cost manufacturing of polycrystalline films by using nanostructured materials. Claim 1 reads:

1. A hetero-crystalline structure comprising:

a first layer of a non-single crystalline material having short range atomic ordering;

a nanostructure of a single crystalline material on the first layer, the nanostructure being integral to a crystallite in the first layer; and

a layer of an insulator material on a surface of the first layer,

the nanostructure being located in an opening through a thickness of the insulator material layer.

US Patent 7875480 - Growing nanowire sensors

http://www.freepatentsonline.com/7875480.html

This patent from HP includes some basic claims to growing horizontally oriented nanowires arrays in a substrate for use as nanoscale sensors. Claim 1 reads:

1. A method of making a sensor, comprising:

substantially laterally growing at least one nanowire having at least two segments between two electrodes, whereby a junction or connection is formed between the at least two segments; and

establishing a sensing material adjacent to the junction or connection, and adjacent to at least a portion of each of the at least two segments, wherein the sensing material has at least two states.

Memristor Patent ReExams and Prior Art

In the past few years there has been increasing interest in the resistance switching properties of nanoscale thin films to develop a new form of non-volatile memory called ReRAM. This interest was peaked in 2008 based upon a paper published in Nature by researchers from HPLabs which connected experimentally observed resistance switching of TiO2 thin films to a memristor model postulated in the 1970's by Leon Chua and Steve Kang. Companies including HP, Sharp, Unity Semiconductor, and Adestos Technology are projecting product release of different variations of ReRAM/memristor in the 2-3 year timeframe.

There are actually several material examples of memristive materials dating back to the the 1960's such as discussed by the article "Switching Phenomena in Titanium Oxide Thin Films," by Argall. However, some of the companies which have been patenting around the concept of ReRAM and memristors have not adequately considered the prior art. Over the past year I have taken a look at several of the companies and patents related to memristors and ReRAM and have begun to compile information on patents which appear to have issued without considering prior art relevant to 35 USC 102 (novelty) or 35 USC 103 (obviousness). In some extreme cases I have filed Ex Parte ReExams for patents which clearly fail to meet patentability standards.

A copy of the Ex Parte ReExam filings as well as copies of filings of prior art under 37 CFR 1.501 is available at this link. A discussion of the business landscape of memristive electronics is available here.   

US Patent 7863625 - Nanocrystal coated nanowire

http://www.freepatentsonline.com/7863625.html

This patent from HP teaches doping semiconductor nanowires to manufacture LEDs and light sensors. Claim 1 reads:

1. A nanowire (100) comprising:

a semiconductor core (102) including one of p-type conductivity and n-type conductivity;

an intermediate semiconductor region (104) surrounding the core including one of an intrinsic semiconductor material and a lightly doped semiconductor material;

a semiconductor outer region (106) including the other of n-type conductivity and p-type conductivity at least partially surrounding the intermediate semiconductor region; and

nanocrystals (108,110) disposed on the surface of the outer region, wherein the core, intrinsic region, and outer region are concentric and coaxial, and the nanocrystals provide electron-conduction paths along the length of the nanowire and spaces between the nanocrystals allow light to penetrate into and to be emitted from the semiconductor regions.

US Patent 7833801 - Free-standing nanowire chemical sensor

http://www.freepatentsonline.com/7833801.html

This patent from HP teaches a method of using arrays of vertically oriented metallic or semiconducting nanowires as a high sensitivity chemical sensor. Claim 1 reads:

1. A method of detecting the presence of an analyte in a test fluid environment, comprising:

providing a first array of free-standing nanowires that is interactive with an analyte, said first array of free-standing nanowires having individual nanowires that are electrically interactive with one another, said first array of free-standing nanowires being electrically coupled to a chip or computer that is human- or machine-readable;

exposing the first array of free-standing nanowires to a test fluid environment suspected of containing the analyte;

measuring an electrical property provided by the first array of free-standing nanowires upon exposure to the test fluid environment.

US Patent 7833616 - Self-aligning nanowire ink

http://www.freepatentsonline.com/7833616.html

For the past decade HP has been using techniques such as nanoimprint lithography to pattern aligned nanowire structures for crossbar electronics. This patent focuses on an alternative method which may be more cost effective based on chemically modified nanowires formed in an ink and capable of self-alignment. Claim 17 reads:

17. An ink formulation for an inkjet printer deposition system, the ink formulation comprising:

a plurality of self-aligning nanowires, a self-aligning nanowire comprising

a nanowire portion and an aligning member attached to the nanowire portion, the aligning member interacting with the aligning member of another self-aligning nanowire of the plurality to align the nanowires; and

 a carrier solution, the plurality of self-aligning nanowires being suspended in the carrier solution, wherein the carrier solution facilitates alignment of the self-aligning nanowires with each other.