Patents by Inventor Naoki Oyanagi

Naoki Oyanagi 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: 20230392288
    Abstract: A SiC single crystal substrate of an embodiment has a diameter being 199 mm or more, wherein the density of threading dislocations per area of 0.25 mm2 arbitrarily selected in the main surface of the SiC single crystal substrate is 5×104/cm2 or less, and the threading dislocations include a threading edge dislocation.
    Type: Application
    Filed: June 2, 2023
    Publication date: December 7, 2023
    Applicant: Resonac Corporation
    Inventors: Takuya YAMAGUCHI, Koji Kamei, Naoki Oyanagi
  • Patent number: 7993453
    Abstract: A method for the production of an SiC single crystal includes the steps of growing a first SiC single crystal in a first direction of growth on a first seed crystal formed of an SiC single crystal, disposing the first SiC single crystal grown on the first seed crystal in a direction parallel or oblique to the first direction of growth and cutting the disposed first SiC single crystal in a direction of a major axis in a cross section perpendicular to the first direction of growth to obtain a second seed crystal, using the second seed crystal to grow thereon in a second direction of growth a second SiC single crystal to a thickness greater than a length of the major axis in the cross section, disposing the second SiC single crystal grown on the second seed crystal in a direction parallel or oblique to the second direction of growth and cutting the disposed second SiC single crystal in a direction of a major axis in a cross section perpendicular to the second direction of growth to obtain a third seed crystal, u
    Type: Grant
    Filed: May 10, 2007
    Date of Patent: August 9, 2011
    Assignee: Showa Denko K.K.
    Inventors: Naoki Oyanagi, Tomohiro Syounai, Yasuyuki Sakaguchi
  • Publication number: 20110111171
    Abstract: A seed crystal for silicon carbide single crystal growth (13) which is attached to the lid of a graphite crucible charged with a raw material silicon carbide powder. The seed crystal includes a seed crystal (4) formed of silicon carbide having one surface defined as a growth surface (4a) for growing a silicon carbide single crystal by a sublimation method, and a carbon film (12) formed on the surface (4b) opposite to the growth surface of the seed crystal (4). Further, the film density of the carbon film (12) is 1.2 g/cm3 to 3.3 g/cm3.
    Type: Application
    Filed: June 12, 2009
    Publication date: May 12, 2011
    Applicant: SHOWA DENKO K.K.
    Inventors: Naoki Oyanagi, Hisao Kogoi
  • Publication number: 20100092366
    Abstract: A water-based polishing slurry for polishing a silicon carbide single crystal, wherein the slurry comprises abrasive particles having a mean particle size of 1 to 400 nm and an inorganic acid, and the slurry has a pH of less than 2 at 20° C.
    Type: Application
    Filed: December 17, 2007
    Publication date: April 15, 2010
    Applicant: SHOWA DENKO K.K.
    Inventors: Hisao Kogoi, Naoki Oyanagi, Yasuyuki Sakaguchi
  • Publication number: 20090184327
    Abstract: A method for the production of an SiC single crystal includes the steps of growing a first SiC single crystal in a first direction of growth on a first seed crystal formed of an SiC single crystal, disposing the first SiC single crystal grown on the first seed crystal in a direction parallel or oblique to the first direction of growth and cutting the disposed first SiC single crystal in a direction of a major axis in a cross section perpendicular to the first direction of growth to obtain a second seed crystal, using the second seed crystal to grow thereon in a second direction of growth a second SiC single crystal to a thickness greater than a length of the major axis in the cross section, disposing the second SiC single crystal grown on the second seed crystal in a direction parallel or oblique to the second direction of growth and cutting the disposed second SiC single crystal in a direction of a major axis in a cross section perpendicular to the second direction of growth to obtain a third seed crystal, u
    Type: Application
    Filed: May 10, 2007
    Publication date: July 23, 2009
    Applicant: Showa Denko K.K.
    Inventors: Naoki Oyanagi, Tomohiro Syounai, Yasuyuki Sakaguchi
  • Patent number: 7455730
    Abstract: A method for producing a single crystal includes supplying a vapor gas from silicon carbide as a raw material to a seed crystal formed of a silicon carbide single crystal to grow the seed crystal. The seed crystal is disposed in a part of crystal growth, with a crystal face of the seed crystal inclined relative to a (0001) plane or (000-1) plane, thereby making crystal growth.
    Type: Grant
    Filed: June 15, 2004
    Date of Patent: November 25, 2008
    Assignee: Showa Denko K.K.
    Inventor: Naoki Oyanagi
  • Patent number: 7371281
    Abstract: A growth crucible (2) for depositing on a seed crystal substrate (5) a silicon carbide single crystal (6) using a sublimate gas of a silicon carbide raw material (11) is disposed inside of an outer crucible (1). During the course of silicon carbide single crystal, a silicon raw material (22) is continuously fed from outside into a space between the growth crucible and the outer crucible for the purpose of vaporizing the silicon raw material. An atmosphere gas surrounding the growth crucible is constituted of a silicon gas. The pressure of the atmosphere silicon gas is controlled to suppress a variation in the composition of the sublimate gas within the growth crucible to thereby grow a large-sized silicon carbide single crystal with few crystal defects on the seed crystal substrate reliably at a high growth rate.
    Type: Grant
    Filed: September 18, 2003
    Date of Patent: May 13, 2008
    Assignee: Showa Denko K.K.
    Inventors: Yasuyuki Sakaguchi, Atsushi Takagi, Naoki Oyanagi
  • Publication number: 20070000432
    Abstract: A method for producing a single crystal includes supplying a vapor gas from silicon carbide as a raw material to a seed crystal formed of a silicon carbide single crystal to grow the seed crystal. The seed crystal is disposed in a part of crystal growth, with a crystal face of the seed crystal inclined relative to a (0001) plane or (000-1) plane, thereby making crystal growth.
    Type: Application
    Filed: June 15, 2004
    Publication date: January 4, 2007
    Applicant: SHOWA DENKO K.K.
    Inventor: Naoki Oyanagi
  • Publication number: 20060144324
    Abstract: A growth crucible (2) for depositing on a seed crystal substrate (5) a silicon carbide single crystal (6) using a sublimate gas of a silicon carbide raw material (11) is disposed inside of an outer crucible (1). During the course of silicon carbide single crystal, a silicon raw material (22) is continuously fed from outside into a space between the growth crucible and the outer crucible for the purpose of vaporizing the silicon raw material. An atmosphere gas surrounding the growth crucible is constituted of a silicon gas. The pressure of the atmosphere silicon gas is controlled to suppress a variation in the composition of the sublimate gas within the growth crucible to thereby grow a large-sized silicon carbide single crystal with few crystal defects on the seed crystal substrate reliably at a high growth rate.
    Type: Application
    Filed: September 18, 2003
    Publication date: July 6, 2006
    Inventors: Yasuyuki Sakaguchi, Atsushi Takagi, Naoki Oyanagi
  • Patent number: 6699105
    Abstract: The present invention comprises a metal bond grind stone having a flat plate portion 10a and a tapered portion 10b; an electrode 13 opposed to the metal bond grind stone with a gap therebetween; voltage applying means 12 for applying a direct-current pulse voltage between the metal bond grind stone and the electrode; conductive liquid supplying means 14 for supplying a conductive liquid 15 between the metal bond grind stone and the electrode; and grind stone moving means 16 for moving the metal bond grind stone in a direction orthogonal to the shaft center thereof, and an ingot 1 of a single crystal SiC is thereby cut at the tapered portion 10b of the metal bond grind stone and the cut surface is then specular-worked at the flat plate portion 10a.
    Type: Grant
    Filed: July 5, 2000
    Date of Patent: March 2, 2004
    Assignees: Riken, Showa Denko K.K.
    Inventors: Hitoshi Ohmori, Yutaka Yamagata, Nobuhide Itoh, Nobuyuki Nagato, Kotaro Yano, Naoki Oyanagi
  • Patent number: 6336971
    Abstract: A silicon carbide single crystal is produced by allowing a vapor evaporated from a silicon raw material to pass through a heated carbon member and then reach a seed crystal substrate on which a silicon carbide single crystal grows. For this production, an apparatus is used, which has a reaction tube, a heating device and a graphite crucible, wherein the lower part of the crucible constitutes a silicon raw material-charging part; a seed crystal substrate is situated at the top of the crucible; and a carbon member, through which the vapor evaporated from a silicon raw material in capable of passing, is disposed intermediately between the silicon raw material-charging part and the seed crystal. As the carbon member, a porous carbon structure, a carbon plate having a plurality of through holes and a carbon particle-packed layer can be mentioned.
    Type: Grant
    Filed: March 13, 2000
    Date of Patent: January 8, 2002
    Assignee: Showa Denko Kabushiki Kaisha
    Inventors: Nobuyuki Nagato, Kunio Komaki, Isamu Yamamoto, Naoki Oyanagi, Shigehiro Nishino