Patents by Inventor Hiroyuki Akinaga

Hiroyuki Akinaga has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 11933752
    Abstract: A gas sensor includes: a gas-sensitive body layer disposed above a substrate and including a metal oxide layer; a first electrode on the gas-sensitive body layer; and a second electrode on the gas-sensitive body layer, being apart from the first electrode by a gap. The gas-sensitive body layer has a resistance change characteristic that reversibly transitions to a high-resistance state and a low-resistance state on basis of a voltage applied across the first electrode and the second electrode. At least a part of the gas-sensitive body layer is exposed to the gap. The gas-sensitive body layer has a resistance that decreases when gas containing a hydrogen atom is in contact with the second electrode.
    Type: Grant
    Filed: July 23, 2019
    Date of Patent: March 19, 2024
    Assignee: NUVOTON TECHNOLOGY CORPORATION JAPAN
    Inventors: Satoru Fujii, Zhiqiang Wei, Kazunari Homma, Shinichi Yoneda, Yasuhisa Naito, Hisashi Shima, Hiroyuki Akinaga
  • Patent number: 11889776
    Abstract: A variable resistance non-volatile memory element includes first and second electrodes and a variable resistance layer between the electrodes. The layer has a resistance value reversibly variable based on an electrical signal. The layer includes a first variable resistance layer that includes an oxygen deficient first metal oxide containing a first metal element and oxygen, and a second variable resistance layer that includes a composite oxide containing the first metal element, a second metal element different from the first metal element, and oxygen, and having a different degree of oxygen deficiency from the first metal oxide. The composite oxide has a lower degree of oxygen deficiency than the first metal oxide. At room temperature, the composite oxide has a smaller oxygen diffusion coefficient than a second metal oxide containing the first metal element and oxygen, and having the degree of oxygen deficiency equal to that of the composite oxide.
    Type: Grant
    Filed: June 23, 2021
    Date of Patent: January 30, 2024
    Assignee: Nuvoton Technology Corporation Japan
    Inventors: Ryutaro Yasuhara, Satoru Fujii, Takumi Mikawa, Atsushi Himeno, Kengo Nishio, Takehide Miyazaki, Hiroyuki Akinaga, Yasuhisa Naitoh, Hisashi Shima
  • Publication number: 20220407003
    Abstract: An information processing device, including a resistive analog neuromorphic device element having a pair of electrodes and an oxide layer provided between the pair of electrodes, and a parallel circuit having a low resistance component and a capacitance component. The parallel circuit and the resistive analog neuromorphic device element are connected in series.
    Type: Application
    Filed: August 26, 2022
    Publication date: December 22, 2022
    Applicant: NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE AND TECHNOLOGY
    Inventors: Hisashi SHIMA, Yasuhisa NAITOH, Hiroyuki AKINAGA, Makoto TAKAHASHI
  • Publication number: 20220254998
    Abstract: A conductive bridge memory device includes a memory cell including a first metal layer; a second metal layer; a first insulator layer having a first surface facing the first metal layer and a second surface facing the second metal layer and being a surface opposite to the first surface, and having a through hole penetrating between the first surface and the second surface; and a liquid layer being formed of liquid containing a liquid electrolyte impregnated in the through hole.
    Type: Application
    Filed: August 28, 2020
    Publication date: August 11, 2022
    Applicants: NATIONAL UNIVERSITY CORPORATION TOTTORI UNIVERSITY, NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE AND TECHNOLOGY, NAGASE & CO., LTD.
    Inventors: Toshiyuki ITOH, Toshiki NOKAMI, Kentaro KINOSHITA, Hisashi SHIMA, Yasuhisa NAITOH, Hiroyuki AKINAGA, Hiroshi SATOU, Shigeki MORII, Kusuo OTA, Atsushi TANAKA
  • Publication number: 20210320248
    Abstract: A variable resistance non-volatile memory element includes first and second electrodes and a variable resistance layer between the electrodes. The layer has a resistance value reversibly variable based on an electrical signal. The layer includes a first variable resistance layer that includes an oxygen deficient first metal oxide containing a first metal element and oxygen, and a second variable resistance layer that includes a composite oxide containing the first metal element, a second metal element different from the first metal element, and oxygen, and having a different degree of oxygen deficiency from the first metal oxide. The composite oxide has a lower degree of oxygen deficiency than the first metal oxide. At room temperature, the composite oxide has a smaller oxygen diffusion coefficient than a second metal oxide containing the first metal element and oxygen, and having the degree of oxygen deficiency equal to that of the composite oxide.
    Type: Application
    Filed: June 23, 2021
    Publication date: October 14, 2021
    Inventors: Ryutaro YASUHARA, Satoru FUJII, Takumi MIKAWA, Atsushi HIMENO, Kengo NISHIO, Takehide MIYAZAKI, Hiroyuki AKINAGA, Yasuhisa NAITOH, Hisashi SHIMA
  • Publication number: 20190346391
    Abstract: A gas sensor includes: a gas-sensitive body layer disposed above a substrate and including a metal oxide layer; a first electrode on the gas-sensitive body layer; and a second electrode on the gas-sensitive body layer, being apart from the first electrode by a gap. The gas-sensitive body layer has a resistance change characteristic that reversibly transitions to a high-resistance state and a low-resistance state on basis of a voltage applied across the first electrode and the second electrode. At least a part of the gas-sensitive body layer is exposed to the gap. The gas-sensitive body layer has a resistance that decreases when gas containing a hydrogen atom is in contact with the second electrode.
    Type: Application
    Filed: July 23, 2019
    Publication date: November 14, 2019
    Inventors: Satoru Fujii, Zhiqiang Wei, Kazunari Homma, Shinichi Yoneda, Yasuhisa Naito, Hisashi Shima, Hiroyuki Akinaga
  • Patent number: 8487415
    Abstract: The present invention provides a rectifier element that has a titanium oxide layer interposed between first and second electrodes containing a transition metal with an electronegativity larger than that of Ti, wherein, in the titanium oxide layer, only the interface on the side facing any one of the electrodes has a stoichiometric composition, and wherein the average composition of the whole layer is represented by the formula TiOx (wherein x satisfies the relationship 1.6?x<2), and wherein the rectifying characteristics can be reversed by applying a reverse electrical signal that exceeds the critical reverse electric power between the first and second electrodes in an opposite direction. The present invention also provides a process for producing a rectifier element, which includes the steps of depositing a first electrode that contains a transition metal with an electronegativity larger than that of Ti on a substrate; depositing a layer of titanium oxide (TiOx, wherein x satisfies the relationship 1.
    Type: Grant
    Filed: October 30, 2008
    Date of Patent: July 16, 2013
    Assignee: National Institute of Advanced Industrial Science and Technology
    Inventors: Hisashi Shima, Hiroyuki Akinaga, Shoji Ishibashi, Tomoyuki Tamura
  • Patent number: 8054674
    Abstract: Provided is a variable resistive element which performs high speed and low power consumption operation. The variable resistive element comprises a metal oxide layer between first and second electrodes wherein electrical resistance between the first and second electrodes reversibly changes in accordance with application of electrical stress across the first and second electrodes. The metal oxide layer has a filament, which is a current path where the density of a current flowing between the first and second electrodes locally increases. A portion including at least the vicinity of an interface between the certain electrode, which is one or both of the first and second electrodes, and the filament, on an interface between the certain electrode and the metal oxide layer is provided with an interface oxide which is an oxide of at least one element included in the certain electrode and different from the oxide of the metal oxide layer.
    Type: Grant
    Filed: April 7, 2008
    Date of Patent: November 8, 2011
    Assignees: Sharp Kabushiki Kaisha, National Institute of Advanced Industrial Science and Technology
    Inventors: Yukio Tamai, Yasunari Hosoi, Nobuyoshi Awaya, Shigeo Ohnishi, Kazuya Ishihara, Hisashi Shima, Hiroyuki Akinaga, Fumiyoshi Takano
  • Patent number: 7964924
    Abstract: A magneto-resistance effect device (1) includes a semiconductor region (2) having a surface provided with a plurality of isolated metal micro-particles (3) of not more than 100 ?m disposed at intervals of not more than 1 ?m, a semiconductor or half-metal cap layer (4) for covering the semiconductor region and a plurality of electrodes (5) disposed on a surface of the cap layer and separated from each other. The device exhibits a high magneto-resistance effect at room temperature, is highly sensible to a magnetic field and can be produced through a simple manufacturing process. The device is formed of a magneto-resistant material easy to match a semiconductor fabrication process. A magnetic field sensor using the device (1) has various excellent characteristics.
    Type: Grant
    Filed: May 24, 2002
    Date of Patent: June 21, 2011
    Assignee: National Institute of Advanced Industrial Science and Technology
    Inventors: Hiroyuki Akinaga, Masaharu Oshima, Masaki Mizuguchi
  • Patent number: 7923711
    Abstract: The present invention provides switching elements having a readout margin suitable for data storage units of nonvolatile memories, which are obtained by improving the resistance ratio of metal oxide thin films having reversible variable resistance properties. The present invention provides switching elements having a metal oxide consisting of a transition metal and oxygen formed between a first electrode and a second electrode, by modifying one or more of the crystal structure, ionic valence number of metal element, and nonstoichiometricity of a stoichiometric compound consisted of the transition metal and oxygen. The present invention also provides methods for producing switching elements having reversible variable resistance characteristics due to electric power application history.
    Type: Grant
    Filed: July 26, 2007
    Date of Patent: April 12, 2011
    Assignees: National Institute of Advanced Industrial Science and Technology, Sharp Corporation
    Inventors: Hisashi Shima, Hiroyuki Akinaga, Fumiyoshi Takano, Yukio Tamai
  • Patent number: 7894239
    Abstract: The variable resistance element of the present invention is a variable resistance element having an electrode, the other electrode, and a metal oxide material sandwiched between the electrodes and having an electrical resistance, between the electrodes, changing reversibly in response to a voltage applied between the electrodes. The variable resistance element further includes, inside the metal oxide material, a low resistance material having a lower electrical resistance than the metal oxide material and being out of contact with at least either one of the electrodes. This makes it possible to reduce a forming voltage for providing a conductive section inside the metal oxide material, without causing a leakage current to increase.
    Type: Grant
    Filed: December 4, 2008
    Date of Patent: February 22, 2011
    Assignees: Sharp Kabushiki Kaisha, National Institute of Advanced Industrial Science and Technology
    Inventors: Yukio Tamai, Yasunari Hosoi, Nobuyoshi Awaya, Shigeo Ohnishi, Kazuya Ishihara, Hisashi Shima, Fumiyoshi Takano, Hiroyuki Akinaga
  • Patent number: 7863594
    Abstract: An objective of the present invention is to provide a switching device that shows two markedly different stable resistance characteristics reversibly and repetitively, and which is applicable to highly integrated nonvolatile memories.
    Type: Grant
    Filed: August 8, 2006
    Date of Patent: January 4, 2011
    Assignee: National Institute of Advanced Industrial Science and Technology
    Inventors: Hiroyuki Akinaga, Shuichiro Yasuda, Isao Inoue, Hidenori Takagi
  • Publication number: 20100276684
    Abstract: The present invention provides a rectifier element that has a titanium oxide layer interposed between first and second electrodes containing a transition metal with an electronegativity larger than that of Ti, wherein, in the titanium oxide layer, only the interface on the side facing any one of the electrodes has a stoichiometric composition, and wherein the average composition of the whole layer is represented by the formula TiOx (wherein x satisfies the relationship 1.6?x<2), and wherein the rectifying characteristics can be reversed by applying a reverse electrical signal that exceeds the critical reverse electric power between the first and second electrodes in an opposite direction. The present invention also provides a process for producing a rectifier element, which includes the steps of depositing a first electrode that contains a transition metal with an electronegativity larger than that of Ti on a substrate; depositing a layer of titanium oxide (TiOx, wherein x satisfies the relationship 1.
    Type: Application
    Filed: October 30, 2008
    Publication date: November 4, 2010
    Inventors: Hisashi Shima, Hiroyuki Akinaga, Shoji Ishibashi, Tomoyuki Tamura
  • Publication number: 20100172170
    Abstract: Provided is a variable resistive element which performs high speed and low power consumption operation. The variable resistive element comprises a metal oxide layer between first and second electrodes wherein electrical resistance between the first and second electrodes reversibly changes in accordance with application of electrical stress across the first and second electrodes. The metal oxide layer has a filament, which is a current path where the density of a current flowing between the first and second electrodes locally increases. A portion including at least the vicinity of an interface between the certain electrode, which is one or both of the first and second electrodes, and the filament, on an interface between the certain electrode and the metal oxide layer is provided with an interface oxide which is an oxide of at least one element included in the certain electrode and different from the oxide of the metal oxide layer.
    Type: Application
    Filed: April 7, 2008
    Publication date: July 8, 2010
    Inventors: Yukio Tamai, Yasunari Hosoi, Nobuyoshi Awaya, Shigeo Ohnishi, Kazuya Ishihara, Hisashi Shima, Hiroyuki Akinaga, Fumiyoshi Takano
  • Publication number: 20100012911
    Abstract: An objective of the present invention is to provide a switching device that shows two markedly different stable resistance characteristics reversibly and repetitively, and which is applicable to highly integrated nonvolatile memories.
    Type: Application
    Filed: August 8, 2006
    Publication date: January 21, 2010
    Applicant: National Institute of Advanced Industrial Science and Technology
    Inventors: Hiroyuki Akinaga, Shuichiro Yasuda, Isao Inoue, Hidenori Takagi
  • Publication number: 20090147558
    Abstract: The variable resistance element of the present invention is a variable resistance element having an electrode, the other electrode, and a metal oxide material sandwiched between the electrodes and having an electrical resistance, between the electrodes, changing reversibly in response to a voltage applied between the electrodes. The variable resistance element further includes, inside the metal oxide material, a low resistance material having a lower electrical resistance than the metal oxide material and being out of contact with at least either one of the electrodes. This makes it possible to reduce a forming voltage for providing a conductive section inside the metal oxide material, without causing a leakage current to increase.
    Type: Application
    Filed: December 4, 2008
    Publication date: June 11, 2009
    Inventors: Yukio Tamai, Yasunari Hosoi, Nobuyoshi Awaya, Shigeo Ohnishi, Kazuya Ishihara, Hisashi Shima, Fumiyoshi Takano, Hiroyuki Akinaga
  • Patent number: 7495215
    Abstract: The present invention provides a probe for a scanning magnetic force microscope having a resolution sufficient to allow observation of a magnetic storage medium with 1200 kFCI or higher recording densities, a method for producing the probe, and a method for forming a ferromagnetic alloy film on a carbon nanotube. In the context of the present invention, the probe for a scanning magnetic force microscope comprises a carbon nanotube whose surface is at least in part coated with a ferromagnetic alloy film consisting of any one of a Co—Fe alloy and a Co—Ni alloy, wherein the arithmetic mean roughness (Ra 10 ?m) of the surface of the ferromagnetic alloy film is controlled to 1.15 nm or less. A method for producing such probes for a scanning magnetic force microscope and a method for forming such a ferromagnetic alloy film on a carbon nanotube, so as to achieve such mean surface roughness by controlling the growth rate of the ferromagnetic alloy film within the range of 1.0 to 2.5 nm/min, is also disclosed.
    Type: Grant
    Filed: December 28, 2005
    Date of Patent: February 24, 2009
    Assignees: National Institute of Advanced Industrial Science and Technology, SII Nanotechnology Inc.
    Inventors: Hiroyuki Akinaga, Yasuyuki Semba, Hiroshi Yokoyama, Masatoshi Yasutake, Hiromi Kuramochi
  • Publication number: 20080166560
    Abstract: The present invention provides a probe for a scanning magnetic force microscope having a resolution sufficient to allow observation of a magnetic storage medium with 1200 kFCI or higher recording densities, a method for producing the probe, and a method for forming a ferromagnetic alloy film on a carbon nanotube. In the context of the present invention, the probe for a scanning magnetic force microscope comprises a carbon nanotube whose surface is at least in part coated with a ferromagnetic alloy film consisting of any one of a Co—Fe alloy and a Co—Ni alloy, wherein the arithmetic mean roughness (Ra 10 ?m) of the surface of the ferromagnetic alloy film is controlled to 1.15 nm or less. A method for producing such probes for a scanning magnetic force microscope and a method for forming such a ferromagnetic alloy film on a carbon nanotube, so as to achieve such mean surface roughness by controlling the growth rate of the ferromagnetic alloy film within the range of 1.0 to 2.5 nm/min, is also disclosed.
    Type: Application
    Filed: December 28, 2005
    Publication date: July 10, 2008
    Applicants: National Institute of Advanced Industrial Science and Technology, SII NanoTechnology Inc.
    Inventors: Hiroyuki Akinaga, Yasuyuki Semba, Hiroshi Yokoyama, Masatoshi Yasutake, Hiromi Kuramochi
  • Publication number: 20080054243
    Abstract: The present invention provides switching elements having a readout margin suitable for data storage units of nonvolatile memories, which are obtained by improving the resistance ratio of metal oxide thin films having reversible variable resistance properties. The present invention provides switching elements having a metal oxide consisting of a transition metal and oxygen formed between a first electrode and a second electrode, by modifying one or more of the crystal structure, ionic valence number of metal element, and nonstoichiometricity of a stoichiometric compound consisted of the transition metal and oxygen.
    Type: Application
    Filed: July 26, 2007
    Publication date: March 6, 2008
    Applicants: National Institute of Advanced Industrial Science and Technology, Sharp Corporation
    Inventors: Hisashi Shima, Hiroyuki Akinaga, Fumiyoshi Takano, Yukio Tamai
  • Publication number: 20070247901
    Abstract: The present invention provides a mesoscopic magnetic body comprising a tabular ferromagnetic body whose planar shape has an axis of symmetry, but which is not symmetric in the direction perpendicular to the axis of symmetry, and wherein the magnetic body shows a circular single domain structure upon removal of the external parallel magnetic field. MRAMs which apply such a mesoscopic magnet and production methods thereof are also provided. As a result, it is possible to control the magnetization direction in nano-scale mesoscopic magnets as well as eliminate the limitation on the number of times in rewriting and writing.
    Type: Application
    Filed: June 4, 2004
    Publication date: October 25, 2007
    Inventors: Hiroyuki Akinaga, Kanta Ono, Masaharu Oshima, Toshiyuki Taniuchi