Patents by Inventor Fumiyoshi Takano

Fumiyoshi Takano 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: 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: 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
  • 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: 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
  • 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