Patents by Inventor Katsumi Okubo

Katsumi Okubo 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: 11972947
    Abstract: A semiconductor laminate film includes a silicon substrate and a semiconductor layer formed on the silicon substrate and containing silicon and germanium. The semiconductor layer having a surface roughness Rms of 1 nm or less. Further, the semiconductor layer satisfies the following relationship t?0.881×x?4.79 where t represents a thickness (nm) of the semiconductor layer, and x represents a ratio of the number of germanium atoms to a sum of the number of silicon atoms and the number of germanium atoms in the semiconductor layer. Also, the semiconductor layer being a mixed crystal semiconductor layer containing silicon and germanium.
    Type: Grant
    Filed: March 10, 2021
    Date of Patent: April 30, 2024
    Assignees: National University Corporation Tokyo University Of Agriculture And Technology, National Institute of Information and Communications Technology
    Inventors: Yoshiyuki Suda, Takahiro Tsukamoto, Akira Motohashi, Kyohei Degura, Katsumi Okubo, Takuma Yagi, Akifumi Kasamatsu, Nobumitsu Hirose, Toshiaki Matsui
  • Patent number: 11492696
    Abstract: A method of producing a semiconductor laminate film includes forming a semiconductor layer containing silicon and germanium on a silicon substrate by a sputtering method. In the sputtering method, a film formation temperature of the semiconductor layer is less than 500° C., and a film formation pressure of the semiconductor layer ranges from 1 mTorr to 11 mTorr, or, a film formation temperature of the semiconductor layer is less than 600° C., and a film formation pressure of the semiconductor layer is equal to or more than 2 mTorr and less than 5 mTorr. The sputtering method uses a sputtering gas having a volume ratio of a hydrogen gas of less than 0.1%, and the semiconductor layer satisfies a relationship of t?0.881×x?4.79, where t represents a thickness (nm) of the semiconductor layer, and x represents a ratio of the number of germanium atoms to a sum of the number of silicon atoms and the number of germanium atoms in the semiconductor layer.
    Type: Grant
    Filed: July 12, 2017
    Date of Patent: November 8, 2022
    Inventors: Yoshiyuki Suda, Takahiro Tsukamoto, Akira Motohashi, Kyohei Degura, Katsumi Okubo, Takuma Yagi, Akifumi Kasamatsu, Nobumitsu Hirose, Toshiaki Matsui
  • Publication number: 20210189549
    Abstract: A semiconductor laminate film includes a silicon substrate and a semiconductor layer formed on the silicon substrate and containing silicon and germanium. The semiconductor layer having a surface roughness Rms of 1 nm or less. Further, the semiconductor layer satisfies the following relationship t?0.881×x?4.79 where t represents a thickness (nm) of the semiconductor layer, and x represents a ratio of the number of germanium atoms to a sum of the number of silicon atoms and the number of germanium atoms in the semiconductor layer. Also, the semiconductor layer being a mixed crystal semiconductor layer containing silicon and germanium.
    Type: Application
    Filed: March 10, 2021
    Publication date: June 24, 2021
    Inventors: Yoshiyuki SUDA, Takahiro TSUKAMOTO, Akira MOTOHASHI, Kyohei DEGURA, Katsumi OKUBO, Takuma YAGI, Akifumi KASAMATSU, Nobumitsu HIROSE, Toshiaki MATSUI
  • Publication number: 20190242008
    Abstract: A method of producing a semiconductor laminate film includes forming a semiconductor layer containing silicon and germanium on a silicon substrate by a sputtering method. In the sputtering method, a film formation temperature of the semiconductor layer is less than 500° C., and a film formation pressure of the semiconductor layer ranges from 1 mTorr to 11 mTorr, or, a film formation temperature of the semiconductor layer is less than 600° C., and a film formation pressure of the semiconductor layer is equal to or more than 2 mTorr and less than 5 mTorr. The sputtering method uses a sputtering gas having a volume ratio of a hydrogen gas of less than 0.1%, and the semiconductor layer satisfies a relationship of t?0.881×x?4.79, where t represents a thickness (nm) of the semiconductor layer, and x represents a ratio of the number of germanium atoms to a sum of the number of silicon atoms and the number of germanium atoms in the semiconductor layer.
    Type: Application
    Filed: July 12, 2017
    Publication date: August 8, 2019
    Inventors: Yoshiyuki SUDA, Takahiro TSUKAMOTO, Akira MOTOHASHI, Kyohei DEGURA, Katsumi OKUBO, Takuma YAGI, Akifumi KASAMATSU, Nobumitsu HIROSE, Toshiaki MATSUI
  • Publication number: 20060022932
    Abstract: A display panel drive circuit according to exemplary embodiments of the invention include a source driver that applies a drive voltage corresponding to a display level of gray to a source line of an active element to drive each pixel of a display panel in which the display level of gray of each pixel is determined depending on accumulated charge between electrodes of each pixel. Exemplary embodiments further include a control unit that controls the drive voltage to be applied to the source line by the source driver and a potential of a common electrode of the display panel at the same potential in a predetermined period.
    Type: Application
    Filed: July 26, 2005
    Publication date: February 2, 2006
    Applicant: SEIKO EPSON CORPORATION
    Inventors: Takahiro Sagawa, Fumio Koyama, Naganori Ito, Yasuyuki Kobayashi, Yasushi Maruyama, Ryosuke Higashi, Katsumi Okubo