Patents by Inventor Yoichiro Tarui

Yoichiro Tarui 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).

  • Publication number: 20090140389
    Abstract: A nitride semiconductor device with a p electrode having no resistance between itself and other electrodes, and a method of manufacturing the same are provided. A p electrode is formed of a first Pd film, a Ta film, and a second Pd film, which is an antioxidant film for preventing oxidation of the Ta film, and on a p-type contact layer of a nitride semiconductor. On the second Pd film, a pad electrode is formed. The second Pd film as an antioxidant film is formed on the entire upper surface of the Ta film which forms the p electrode, to prevent oxidation of the Ta film. This inhibits the resistance between the p electrode and the pad electrode, thereby preventing a failure in contact between the p electrode and the pad electrode and providing the low-resistance p electrode.
    Type: Application
    Filed: November 11, 2008
    Publication date: June 4, 2009
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Katsuomi Shiozawa, Kyozo Kanamoto, Toshiyuki Oishi, Hiroshi Kurokawa, Kenichi Ohtsuka, Yoichiro Tarui, Yasunori Tokuda
  • Patent number: 7285465
    Abstract: A semiconductor device and its manufacturing method are provided in which the trade-off relation between channel resistance and JFET resistance, an obstacle to device miniaturization, is improved and the same mask is used to form a source region and a base region by ion implantation. In a vertical MOSFET that uses SiC, a source region and a base region are formed by ion implantation using the same tapered mask to give the base region a tapered shape. The taper angle of the tapered mask is set to 30° to 60° when the material of the tapered mask has the same range as SiC in ion implantation, and to 20° to 45° when the material of the tapered mask is SiO2.
    Type: Grant
    Filed: February 15, 2006
    Date of Patent: October 23, 2007
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Yoichiro Tarui, Ken-ichi Ohtsuka, Masayuki Imaizumi, Hiroshi Sugimoto, Tetsuya Takami
  • Publication number: 20060134847
    Abstract: A semiconductor device and its manufacturing method are provided in which the trade-off relation between channel resistance and JFET resistance, an obstacle to device miniaturization, is improved and the same mask is used to form a source region and a base region by ion implantation. In a vertical MOSFET that uses SiC, a source region and a base region are formed by ion implantation using the same tapered mask to give the base region a tapered shape. The taper angle of the tapered mask is set to 30° to 60° when the material of the tapered mask has the same range as SiC in ion implantation, and to 20° to 45° when the material of the tapered mask is SiO2.
    Type: Application
    Filed: February 15, 2006
    Publication date: June 22, 2006
    Applicant: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Yoichiro Tarui, Ken-ichi Ohtsuka, Masayuki Imaizumi, Hiroshi Sugimoto, Tetsuya Takami
  • Publication number: 20060118812
    Abstract: A semiconductor device includes an anode electrode in Schottky contact with an n-type drift layer formed in an SiC substrate and a JTE region formed outside the anode electrode. The JTE region is made up of a first p-type zone formed in an upper portion of the drift layer under an edge of the anode electrode and a second p-type zone formed outside the first p-type zone having a lower surface impurity concentration than the first p-type zone. The second p-type zone is provided 15 ?m or more outwardly away from the edge of the anode electrode. The surface impurity concentration of the first p-type zone ranges from 1.8×1013 to 4×1013 cm?2, and that of the second p-type zone ranges from 1×1013 to 2.5×1013 cm?2.
    Type: Application
    Filed: June 2, 2005
    Publication date: June 8, 2006
    Applicant: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Kenichi Ohtsuka, Yoichiro Tarui, Yoshinori Matsuno, Kenichi Kuroda, Hiroshi Sugimoto
  • Patent number: 7029969
    Abstract: A semiconductor device and its manufacturing method in which the trade-off relationship between channel resistance and JFET resistance is improved. The same mask is used to form a source region and a base region by ion implantation. In a vertical MOSFET including SiC, a source region and a base region are formed by ion implantation using the same tapered mask to give the base region a tapered shape. The taper angle of the tapered mask is set to 30° to 60° when the material of the tapered mask has the same range as SiC in ion implantation, and to 20° to 45° when the material of the tapered mask is SiO2.
    Type: Grant
    Filed: March 18, 2004
    Date of Patent: April 18, 2006
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Yoichiro Tarui, Ken-ichi Ohtsuka, Masayuki Imaizumi, Hiroshi Sugimoto, Tetsuya Takami
  • Publication number: 20040188755
    Abstract: A semiconductor device and its manufacturing method in which the trade-off relationship between channel resistance and JFET resistance is improved. The same mask is used to form a source region and a base region by ion implantation. In a vertical MOSFET including SiC, a source region and a base region are formed by ion implantation using the same tapered mask to give the base region a tapered shape. The taper angle of the tapered mask is set to 30° to 60° when the material of the tapered mask has the same range as SiC in ion implantation, and to 20° to 45° when the material of the tapered mask is SiO2.
    Type: Application
    Filed: March 18, 2004
    Publication date: September 30, 2004
    Applicant: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Yoichiro Tarui, Ken-ichi Ohtsuka, Masayuki Imaizumi, Hiroshi Sugimoto, Tetsuya Takami
  • Patent number: 6307232
    Abstract: A diode having a p+ semiconductor region, an n− drift region and an n+ semiconductor region is formed in an SOI layer. An SiC layer is formed in the bottom surface of a semiconductor layer. Further, a capacitive coupled multiple field plate including conductive layers is formed between cathode and anode electrodes. As a result, a semiconductor device with a lateral high breakdown voltage element having extremely high breakdown voltage which is never restricted by electric field concentration in the surface of the SOI layer can be achieved.
    Type: Grant
    Filed: November 25, 1997
    Date of Patent: October 23, 2001
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Hajime Akiyama, Yoichiro Tarui