Patents by Inventor Hironori Itoh

Hironori Itoh 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: 20210320005
    Abstract: When a value obtained by dividing the number of the one or more second regions by a total of the number of the one or more first regions and the number of the one or more second regions is defined as a first defect free area ratio, a value obtained by dividing the number of the one or more fourth regions by a total of the number of the one or more third regions and the number of the one or more fourth regions is defined as a second defect free area ratio, and a value obtained by dividing the number of the one or more macroscopic defects by an area of the central region is defined as X cm?2, A is smaller than B, B is less than or equal to 4, X is more than 0 and less than 4, and a Formula 1 is satisfied.
    Type: Application
    Filed: June 14, 2019
    Publication date: October 14, 2021
    Inventors: Kenji KANBARA, Hironori ITOH, Tsutomu HORI
  • Patent number: 11004941
    Abstract: A silicon carbide epitaxial substrate has a silicon carbide single-crystal substrate and a silicon carbide layer. An average value of carrier concentration in the silicon carbide layer is not less than 1×1015 cm?3 and not more than 5×1016 cm?3. In-plane uniformity of the carrier concentration is not more than 2%. The second main surface has: a groove 80 extending in one direction along the second main surface, a width of the groove in the one direction being twice or more as large as a width thereof in a direction perpendicular to the one direction, and a maximum depth of the groove from the second main surface being not more than 10 nm; and a carrot defect. A value obtained by dividing a number of the carrot defects by a number of the grooves is not more than 1/500.
    Type: Grant
    Filed: August 6, 2020
    Date of Patent: May 11, 2021
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Keiji Wada, Hironori Itoh, Taro Nishiguchi
  • Patent number: 10865501
    Abstract: A silicon carbide epitaxial substrate has a silicon carbide single-crystal substrate and a silicon carbide layer. A first ratio of an absolute value of a difference between a dopant density in a first end region and a dopant density in a central region to an average value of the dopant density in the first end region and the dopant density in the central region is not more than 40%. A second ratio of an absolute value of a difference between a dopant density in a second end region and the dopant density in the central region to an average value of the dopant density in the second end region and the dopant density in the central region is not more than 40%.
    Type: Grant
    Filed: July 4, 2016
    Date of Patent: December 15, 2020
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Tsutomu Hori, Hironori Itoh
  • Patent number: 10825903
    Abstract: Assuming that one or more defects satisfying relations of Formula 1 and Formula 2 are first defects, and one or more defects satisfying relations of Formula 3 and Formula 2 are second defects, where an off angle is ?°, the thickness of a silicon carbide layer in a direction perpendicular to a second main surface is W ?m, the width of each of the one or more defects in a direction obtained by projecting a direction parallel to an off direction onto the second main surface is L ?m, and the width of each of the one or more defects in a direction perpendicular to the off direction and parallel to the second main surface is Y ?m, a value obtained by dividing the number of the second defects by the sum of the number of the first defects and the number of the second defects is greater than 0.5.
    Type: Grant
    Filed: October 3, 2017
    Date of Patent: November 3, 2020
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Keiji Wada, Tsutomu Hori, Hironori Itoh
  • Patent number: 10811500
    Abstract: It is assumed that a defect satisfying relations of Formula 1 and Formula 2 is a first defect, where an off angle is ?. It is assumed that a defect having an elongated shape when viewed in a direction perpendicular to the second main surface, and satisfying relations of Formula 3 and Formula 4 is a second defect. A value obtained by dividing the number of the second defect by the sum of the number of the first defect and the number of the second defect is greater than 0.5.
    Type: Grant
    Filed: December 1, 2017
    Date of Patent: October 20, 2020
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Hironori Itoh, Keiji Wada, Tsutomu Hori
  • Patent number: 10770550
    Abstract: A silicon carbide epitaxial substrate has a silicon carbide single-crystal substrate and a silicon carbide layer. An average value of carrier concentration in the silicon carbide layer is not less than 1×1015 cm?3 and not more than 5×1016 cm?3. In-plane uniformity of the carrier concentration is not more than 2%. The second main surface has: a groove 80 extending in one direction along the second main surface, a width of the groove in the one direction being twice or more as large as a width thereof in a direction perpendicular to the one direction, and a maximum depth of the groove from the second main surface being not more than 10 nm; and a carrot defect. A value obtained by dividing a number of the carrot defects by a number of the grooves is not more than 1/500.
    Type: Grant
    Filed: October 23, 2019
    Date of Patent: September 8, 2020
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Keiji Wada, Hironori Itoh, Taro Nishiguchi
  • Patent number: 10697086
    Abstract: In forming of a silicon carbide layer, when an X axis indicates a first value representing, in percentage, a value obtained by dividing a flow rate of silane by a flow rate of hydrogen and a Y axis indicates a second value representing a flow rate of ammonia in sccm, the first value and the second value fall within a quadrangular region surrounded by first coordinates, second coordinates, third coordinates, and fourth coordinates in XY plane coordinates. The first coordinates are (0.05, 6.5×10?4). The second coordinates are (0.05, 4.5×10?3). The third coordinates are (0.22, 1.2×10?2). The fourth coordinates are (0.22, 1.3×10?1). After the forming of the silicon carbide layer, an average value of carrier concentration of the silicon carbide layer is more than or equal to 1×1015 cm?3 and less than or equal to 2×1016 cm?3.
    Type: Grant
    Filed: August 2, 2016
    Date of Patent: June 30, 2020
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Keiji Wada, Hideyuki Doi, Hironori Itoh
  • Patent number: 10612160
    Abstract: An epitaxial wafer includes a silicon carbide film having a first main surface. A groove portion is formed in the first main surface. The groove portion extends in one direction along the first main surface. Moreover, a width of the groove portion in the one direction is twice or more as large as a width of the groove portion in a direction perpendicular to the one direction. Moreover, a maximum depth of the groove portion from the first main surface is not more than 10 nm.
    Type: Grant
    Filed: March 23, 2018
    Date of Patent: April 7, 2020
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Taro Nishiguchi, Jun Genba, Hironori Itoh, Tomoaki Hatayama, Hideyuki Doi
  • Publication number: 20200052074
    Abstract: A silicon carbide epitaxial substrate has a silicon carbide single-crystal substrate and a silicon carbide layer. An average value of carrier concentration in the silicon carbide layer is not less than 1×1015 cm?3 and not more than 5×1016 cm?3. In-plane uniformity of the carrier concentration is not more than 2%. The second main surface has: a groove 80 extending in one direction along the second main surface, a width of the groove in the one direction being twice or more as large as a width thereof in a direction perpendicular to the one direction, and a maximum depth of the groove from the second main surface being not more than 10 nm; and a carrot defect. A value obtained by dividing a number of the carrot defects by a number of the grooves is not more than 1/500.
    Type: Application
    Filed: October 23, 2019
    Publication date: February 13, 2020
    Applicant: Sumitomo Electric Industries, Ltd.
    Inventors: Keiji Wada, Hironori Itoh, Taro Nishiguchi
  • Publication number: 20200013858
    Abstract: It is assumed that a defect satisfying relations of Formula 1 and Formula 2 is a first defect, where an off angle is ?. It is assumed that a defect having an elongated shape when viewed in a direction perpendicular to the second main surface, and satisfying relations of Formula 3 and Formula 4 is a second defect. A value obtained by dividing the number of the second defect by the sum of the number of the first defect and the number of the second defect is greater than 0.5.
    Type: Application
    Filed: December 1, 2017
    Publication date: January 9, 2020
    Applicant: Sumitomo Electric Industries, Ltd.
    Inventors: Hironori ITOH, Keiji WADA, Tsutomu HORI
  • Patent number: 10490634
    Abstract: A silicon carbide epitaxial substrate has a silicon carbide single-crystal substrate and a silicon carbide layer. An average value of carrier concentration in the silicon carbide layer is not less than 1×1015 cm?3 and not more than 5×10 cm?3. In-plane uniformity of the carrier concentration is not more than 2%. The second main surface has: a groove 80 extending in one direction along the second main surface, a width of the groove in the one direction being twice or more as large as a width thereof in a direction perpendicular to the one direction, and a maximum depth of the groove from the second main surface being not more than 10 nm; and a carrot defect. A value obtained by dividing a number of the carrot defects by a number of the grooves is not more than 1/500.
    Type: Grant
    Filed: August 23, 2016
    Date of Patent: November 26, 2019
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Keiji Wada, Hironori Itoh, Taro Nishiguchi
  • Publication number: 20190355820
    Abstract: Assuming that one or more defects satisfying relations of Formula 1 and Formula 2 are first defects, and one or more defects satisfying relations of Formula 3 and Formula 2 are second defects, where an off angle is ?°, the thickness of a silicon carbide layer in a direction perpendicular to a second main surface is W ?m, the width of each of the one or more defects in a direction obtained by projecting a direction parallel to an off direction onto the second main surface is L ?m, and the width of each of the one or more defects in a direction perpendicular to the off direction and parallel to the second main surface is Y ?m, a value obtained by dividing the number of the second defects by the sum of the number of the first defects and the number of the second defects is greater than 0.5.
    Type: Application
    Filed: October 3, 2017
    Publication date: November 21, 2019
    Applicant: Sumitomo Electric Industries, Ltd.
    Inventors: Keiji WADA, Tsutomu HORI, Hironori ITOH
  • Patent number: 10472736
    Abstract: An epitaxial wafer includes a silicon carbide film having a first main surface. A groove portion is formed in the first main surface. The groove portion extends in one direction along the first main surface. Moreover, a width of the groove portion in the one direction is twice or more as large as a width of the groove portion in a direction perpendicular to the one direction. Moreover, a maximum depth of the groove portion from the first main surface is not more than 10 nm.
    Type: Grant
    Filed: March 23, 2018
    Date of Patent: November 12, 2019
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Taro Nishiguchi, Jun Genba, Hironori Itoh, Tomoaki Hatayama, Hideyuki Doi
  • Patent number: 10396163
    Abstract: A silicon carbide epitaxial substrate includes a silicon carbide single crystal substrate and a silicon carbide layer. The silicon carbide single crystal substrate has a first main surface. The silicon carbide layer is on the first main surface. The silicon carbide layer includes a second main surface opposite to a surface thereof in contact with the silicon carbide single crystal substrate. The second main surface has a maximum diameter of more than or equal to 100 mm. The second main surface includes an outer peripheral region which is within 3 mm from an outer edge of the second main surface, and a central region surrounded by the outer peripheral region. The central region has a haze of less than or equal to 75 ppm.
    Type: Grant
    Filed: August 4, 2016
    Date of Patent: August 27, 2019
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Keiji Wada, Hironori Itoh, Takemi Terao, Kenji Kanbara, Taro Nishiguchi
  • Publication number: 20190019868
    Abstract: A silicon carbide epitaxial substrate includes a silicon carbide single crystal substrate and a silicon carbide layer. The silicon carbide single crystal substrate has a first main surface. The silicon carbide layer is on the first main surface. The silicon carbide layer includes a second main surface opposite to a surface thereof in contact with the silicon carbide single crystal substrate. The second main surface has a maximum diameter of more than or equal to 100 mm. The second main surface includes an outer peripheral region which is within 3 mm from an outer edge of the second main surface, and a central region surrounded by the outer peripheral region. The central region has a haze of less than or equal to 75 ppm.
    Type: Application
    Filed: August 4, 2016
    Publication date: January 17, 2019
    Applicant: Sumitomo Electric Industries, Ltd.
    Inventors: Keiji Wada, Hironori Itoh, Takemi Terao, Kenji Kanbara, Taro Nishiguchi
  • Publication number: 20190013198
    Abstract: A silicon carbide epitaxial substrate includes: a silicon carbide single crystal substrate; a first silicon carbide layer on the silicon carbide single crystal substrate, the first silicon carbide layer having a first concentration of carriers; and a second silicon carbide layer on the first silicon carbide layer, the second silicon carbide layer having a second concentration of carriers. A transition region in which the concentration of the carriers is changed between the first concentration and the second concentration has a width of less than or equal to 1 ?m. A ratio of a standard deviation of the second concentration to an average value of the second concentration is less than or equal to 5%, the ratio being defined as uniformity of the second concentration in a central region. The central region has an arithmetic mean roughness of less than or equal to 0.5 nm.
    Type: Application
    Filed: December 14, 2016
    Publication date: January 10, 2019
    Inventors: Hironori Itoh, Taro Nishiguchi, Kenji Hiratsuka
  • Patent number: 10121865
    Abstract: The silicon carbide layer has a second main surface. The second main surface has a peripheral region within 5 mm from an outer edge thereof, and a central region surrounded by the peripheral region. The silicon carbide layer has a central surface layer. An average value of a carrier concentration in the central surface layer is not less than 1×1014 cm?3 and not more than 5×1016 cm?3. Circumferential uniformity of the carrier concentration is not more than 2%, and in-plane uniformity of the carrier concentration is not more than 10%. An average value of a thickness of a portion of the silicon carbide layer sandwiched between the central region and the silicon carbide single-crystal substrate is not less than 5 ?m. Circumferential uniformity of the thickness is not more than 1%, and in-plane uniformity of the thickness is not more than 4%.
    Type: Grant
    Filed: July 4, 2016
    Date of Patent: November 6, 2018
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Tsutomu Hori, Hironori Itoh
  • Publication number: 20180277635
    Abstract: A silicon carbide epitaxial substrate has a silicon carbide single-crystal substrate and a silicon carbide layer. An average value of carrier concentration in the silicon carbide layer is not less than 1×1015 cm?3 and not more than 5×1016 cm?3. In-plane uniformity of the carrier concentration is not more than 2%. The second main surface has: a groove 80 extending in one direction along the second main surface, a width of the groove in the one direction being twice or more as large as a width thereof in a direction perpendicular to the one direction, and a maximum depth of the groove from the second main surface being not more than 10 nm; and a carrot defect. A value obtained by dividing a number of the carrot defects by a number of the grooves is not more than 1/500.
    Type: Application
    Filed: August 23, 2016
    Publication date: September 27, 2018
    Applicant: Sumitomo Electric Industries, Ltd.
    Inventors: Keiji Wada, Hironori Itoh, Taro Nishiguchi
  • Publication number: 20180245238
    Abstract: A silicon carbide epitaxial substrate has a silicon carbide single-crystal substrate and a silicon carbide layer. A first ratio of an absolute value of a difference between a dopant density in a first end region and a dopant density in a central region to an average value of the dopant density in the first end region and the dopant density in the central region is not more than 40%. A second ratio of an absolute value of a difference between a dopant density in a second end region and the dopant density in the central region to an average value of the dopant density in the second end region and the dopant density in the central region is not more than 40%.
    Type: Application
    Filed: July 4, 2016
    Publication date: August 30, 2018
    Inventors: Tsutomu Hori, Hironori Itoh
  • Publication number: 20180237942
    Abstract: In forming of a silicon carbide layer, when an X axis indicates a first value representing, in percentage, a value obtained by dividing a flow rate of silane by a flow rate of hydrogen and a Y axis indicates a second value representing a flow rate of ammonia in sccm, the first value and the second value fall within a quadrangular region surrounded by first coordinates, second coordinates, third coordinates, and fourth coordinates in XY plane coordinates. The first coordinates are (0.05, 6.5×10?4). The second coordinates are (0.05, 4.5×10?3). The third coordinates are (0.22, 1.2×10?2). The fourth coordinates are (0.22, 1.3×10?1). After the forming of the silicon carbide layer, an average value of carrier concentration of the silicon carbide layer is more than or equal to 1×1015 cm?3 and less than or equal to 2×1016 cm?3.
    Type: Application
    Filed: August 2, 2016
    Publication date: August 23, 2018
    Inventors: Keiji Wada, Hideyuki Doi, Hironori Itoh