Patents by Inventor Yasuyuki Sakaguchi

Yasuyuki Sakaguchi 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: 20220074840
    Abstract: The invention provides a method of inspecting a lubricating oil composition and a method of producing a lubricating oil composition. The inspecting method is capable of stably reproducing wear resistance characteristics by using a relatively easy measuring method even in the case where the lubricating oil composition contains a fullerene. In the method of inspecting the lubricating oil composition, the particle size (r) of particles present in the lubricating oil composition containing a base oil and fullerene is measured, and the lubricating oil composition is sorted on the basis of a predetermined range of the particle size (r) set by the relationship between the measured value of the particle size (r) and the measured value of the wear coefficient of the lubricating oil composition.
    Type: Application
    Filed: November 15, 2021
    Publication date: March 10, 2022
    Applicant: SHOWA DENKO K.K.
    Inventors: Ryuji MONDEN, Yasuyuki SAKAGUCHI, Hitomi KANE, Kunio KONDO
  • Publication number: 20140339571
    Abstract: A SiC epitaxial wafer obtained by forming a SiC epitaxial layer on a 4H—SiC single-crystal substrate that is tilted at an off-angle of 0.4° to 5°, wherein linear density of step bunchings, which are connected to shallow pits which are due to screw dislocation in the SiC epitaxial wafer, is 5 mm?1 or less.
    Type: Application
    Filed: July 30, 2014
    Publication date: November 20, 2014
    Applicant: SHOWA DENKO K.K.
    Inventors: Kenji MOMOSE, Yutaka TAJIMA, Yasuyuki SAKAGUCHI, Michiya ODAWARA, Yoshihiko MIYASAKA
  • Patent number: 8823015
    Abstract: Provided is a silicon carbide epitaxial wafer, the entire surface of which is free of step bunching. Also provided is a method for manufacturing said silicon carbide epitaxial wafer. The provided method for manufacturing a silicon carbide semiconductor device includes: a step wherein a 4H—SiC single-crystal substrate having an off-axis angle of 5° or less is polished until the lattice disorder layer on the surface of the substrate is 3 nm or less; a step wherein, in a hydrogen atmosphere, the polished substrate is brought to a temperature between 1400° C. and 1600° C. and the surface of the substrate is cleaned; a step wherein silicon carbide is epitaxially grown on the surface of the cleaned substrate as the amounts of SiH4 gas and C3H8 gas considered necessary for epitaxially growing silicon carbide are supplied simultaneously at a carbon-to-silicon concentration ratio between 0.7 and 1.
    Type: Grant
    Filed: August 25, 2010
    Date of Patent: September 2, 2014
    Assignee: Showa Denko K.K.
    Inventors: Kenji Momose, Yutaka Tajima, Yasuyuki Sakaguchi, Michiya Odawara, Yoshihiko Miyasaka
  • Patent number: 8513674
    Abstract: A method of manufacturing of a semiconductor device (101) includes: a fine pattern forming step of forming p-type impurity regions (3, 4) and surface ohmic contact electrodes (5) using a stepper, after forming an N-type epitaxial layer (2) on a SiC single-crystal substrate (1); a protective film planarizing step of forming a protective film so as to cover the surface ohmic contact electrodes (5) and performing planarization of the protective film; a substrate thinning step of thinning the SiC single-crystal substrate (1); a backside ohmic contact electrode forming step of forming a backside ohmic contact electrode (7) on the SiC single-crystal substrate (1); a surface Schottky contact electrode forming step of forming a Schottky metal portion (8) connected to the p-type impurity regions (3, 4) and the surface ohmic contact electrodes (5); and a step of forming a surface pad electrode (9) that covers the Schottky metal portion (8).
    Type: Grant
    Filed: November 25, 2009
    Date of Patent: August 20, 2013
    Assignee: Showa Denko K.K.
    Inventors: Akihiko Sugai, Yasuyuki Sakaguchi
  • Publication number: 20120146056
    Abstract: Provided is a silicon carbide epitaxial wafer, the entire surface of which is free of step bunching. Also provided is a method for manufacturing said silicon carbide epitaxial wafer. The provided method for manufacturing a silicon carbide semiconductor device includes: a step wherein a 4H—SiC single-crystal substrate having an off-axis angle of 5° or less is polished until the lattice disorder layer on the surface of the substrate is 3 nm or less; a step wherein, in a hydrogen atmosphere, the polished substrate is brought to a temperature between 1400° C. and 1600° C. and the surface of the substrate is cleaned; a step wherein silicon carbide is epitaxially grown on the surface of the cleaned substrate as the amounts of SiH4 gas and C3H8 gas considered necessary for epitaxially growing silicon carbide are supplied simultaneously at a carbon-to-silicon concentration ratio between 0.7 and 1.
    Type: Application
    Filed: August 25, 2010
    Publication date: June 14, 2012
    Applicant: SHOWA DENKO K.K.
    Inventors: Kenji Momose, Yutaka Tajima, Yasuyuki Sakaguchi, Michiya Odawara, Yoshihiko Miyasaka
  • Publication number: 20110233563
    Abstract: A method of manufacturing of a semiconductor device (101) includes: a fine pattern forming step of forming p-type impurity regions (3, 4) and surface ohmic contact electrodes (5) using a stepper, after forming an N-type epitaxial layer (2) on a SiC single-crystal substrate (1); a protective film planarizing step of forming a protective film so as to cover the surface ohmic contact electrodes (5) and performing planarization of the protective film; a substrate thinning step of thinning the SiC single-crystal substrate (1); a backside ohmic contact electrode forming step of forming a backside ohmic contact electrode (7) on the SiC single-crystal substrate (1); a surface Schottky contact electrode forming step of forming a Schottky metal portion (8) connected to the p-type impurity regions (3, 4) and the surface ohmic contact electrodes (5); and a step of forming a surface pad electrode (9) that covers the Schottky metal portion (8).
    Type: Application
    Filed: November 25, 2009
    Publication date: September 29, 2011
    Applicant: SHOWA DENKO K.K.
    Inventors: Akihiko Sugai, Yasuyuki Sakaguchi
  • 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: 20110183113
    Abstract: There is provided a silicon carbide single crystal substrate having adhered particles that cause crystal defects removed therefrom and has high surface cleanliness, the silicon carbide single crystal substrate, wherein a density of first adhered particles attached onto one surface of the substrate and having a height of 100 nm or more is one particle/cm2 or less, and also a density of second adhered particles attached onto one surface of the substrate and having a height of less than 100 nm is 1,500 particles/cm2 or less.
    Type: Application
    Filed: September 28, 2009
    Publication date: July 28, 2011
    Applicant: SHOWA DENKO K.K.
    Inventor: Yasuyuki Sakaguchi
  • 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: 20100028240
    Abstract: A method for producing an SiC single crystal comprises providing a low temperature region and a high temperature region in a crystal growth crucible (6); disposing a seed crystal substrate formed of an SiC single crystal in the low temperature region of the crystal growth crucible; disposing an SiC raw material in the high temperature region; and depositing a sublimation gas that sublimes from the SiC raw material on the seed crystal substrate to grow the SiC single crystal. A material used in the crucible member where the seed crystal is disposed is a material having a room-temperature linear expansion coefficient that differs from that of SiC by 1.0×10?6/K or less, and the crucible member where the seed crystal is disposed is made of Sic.
    Type: Application
    Filed: October 4, 2007
    Publication date: February 4, 2010
    Inventors: Tomohiro Shonai, Hisao Kogoi, 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: 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: 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: 7029940
    Abstract: Ammonia for use in the manufacture of a GaN-type compound semiconductor, filled in a charging container 18 such that at least a part of the ammonia is liquid and the liquid phase ammonia has a water concentration determined by a Fourier-transform infrared spectroscopy (FT-IR) of 0.5 vol ppm or less, is introduced in the gaseous state into a reaction chamber 11 housing therein a substrate 1, and a layer comprising a GaN-type compound started from this ammonia is formed on the substrate 1.
    Type: Grant
    Filed: April 12, 2004
    Date of Patent: April 18, 2006
    Assignee: Showa Denko Kabushiki Kaisha
    Inventors: Hideki Hayashida, Taizo Ito, Yasuyuki Sakaguchi
  • Publication number: 20040192048
    Abstract: Ammonia for use in the manufacture of a GaN-type compound semiconductor, filled in a charging container 18 such that at least a part of the ammonia is liquid and the liquid phase ammonia has a water concentration determined by a Fourier-transform infrared spectroscopy (FT-IR) of 0.5 vol ppm or less, is introduced in the gaseous state into a reaction chamber 11 housing therein a substrate 1, and a layer comprising a GaN-type compound started from this ammonia is formed on the substrate 1.
    Type: Application
    Filed: April 12, 2004
    Publication date: September 30, 2004
    Applicant: SHOWA DENKO K.K.
    Inventors: Hideki Hayashida, Taizo Ito, Yasuyuki Sakaguchi
  • Patent number: 6719842
    Abstract: Ammonia for use in the manufacture of a GaN-type compound semiconductor, filled in a charging container 18 such that at least a part of the ammonia is liquid and the liquid phase ammonia has a water concentration determined by a Fourier-transform infrared spectroscopy (FT-IR) of 0.5 vol ppm or less, is introduced in the gaseous state into a reaction chamber 11 housing therein a substrate 1, and a layer comprising a GaN-type compound started from this ammonia is formed on the substrate 1.
    Type: Grant
    Filed: December 29, 1999
    Date of Patent: April 13, 2004
    Assignee: Showa Denko Kabushiki Kaisha
    Inventors: Hideki Hayashida, Taizo Ito, Yasuyuki Sakaguchi
  • Publication number: 20030033973
    Abstract: Ammonia for use in the manufacture of a GaN-type compound semiconductor, filled in a charging container 18 such that at least a part of the ammonia is liquid and the liquid phase ammonia has a water concentration determined by a Fourier-transform infrared spectroscopy (FT-IR) of 0.5 vol ppm or less, is introduced in the gaseous state into a reaction chamber 11 housing therein a substrate 1, and a layer comprising a GaN-type compound started from this ammonia is formed on the substrate 1.
    Type: Application
    Filed: December 29, 1999
    Publication date: February 20, 2003
    Inventors: HIDEKI HAYASHIDA, TAIZO ITO, YASUYUKI SAKAGUCHI
  • Patent number: 5744829
    Abstract: An AlGaInP light-emitting diode includes a double hetero-junction light-emitting structure of (Al.sub.x Ga.sub.1-x).sub.y In.sub.1-y P on a GaAs substrate. A multi-film reflection layer is provided between the GaAs substrate and the double hetero-junction light-emitting structure. The layers forming the double hetero-junction are lattice matched with the GaAs substrate at an epitaxial growth temperature. A GaP current diffusion layer is disposed on the upper surface of the double hetero-junction light-emitting structure, and ohmic electrodes are provided on the underside of the GaAs substrate and on the upper surface of the current diffusion layer.
    Type: Grant
    Filed: December 26, 1996
    Date of Patent: April 28, 1998
    Assignee: Showa Denko K. K.
    Inventors: Shigetaka Murasato, Yasuyuki Sakaguchi
  • Patent number: 5656829
    Abstract: A semiconductor light emitting diode includes a compound semiconductor substrate and a double-hetero structure of (Al.sub.x Ga.sub.1-x).sub.y In.sub.1-y P (0.ltoreq.x.ltoreq.1, 0<y<1) as an active layer, and an upper clad layer of the double-hetero structure has a larger band gap energy (Eg) than the band gap energy of the active layer and has a thickness of 3-50 .mu.m.
    Type: Grant
    Filed: July 5, 1995
    Date of Patent: August 12, 1997
    Assignee: Showa Denko K.K.
    Inventors: Yasuyuki Sakaguchi, Sigemasa Nakamura, Yasuo Hosokawa, Yutaka Saito