Patents by Inventor Tsutomu Hori

Tsutomu Hori 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: 20180202068
    Abstract: A method of manufacturing a silicon carbide epitaxial substrate includes: performing degassing by heating a reaction chamber of a film formation apparatus; and using a gas including silicon atoms, a gas including carbon atoms, an ammonia gas, and a hydrogen gas serving as a carrier gas and having a dew point equal to or less than ?100° C., epitaxially growing a silicon carbide layer on a surface of a silicon carbide single-crystal substrate within the reaction chamber.
    Type: Application
    Filed: July 28, 2016
    Publication date: July 19, 2018
    Inventor: Tsutomu HORI
  • Patent number: 9856583
    Abstract: A method of manufacturing a silicon carbide single crystal includes steps of preparing a crucible, a source material disposed toward a bottom surface in the crucible, a seed crystal disposed to face the source material toward a top surface in the crucible, a resistive heater, and a heat insulator configured to be able to accommodate the crucible therein, measuring a mass of at least a portion of the heat insulator, comparing a measured value of the mass obtained in the measuring step with a threshold value, and growing a silicon carbide single crystal on the seed crystal by sublimation of the source material by heating the crucible placed in the heat insulator with the resistive heater. When the measured value of the mass is lower than the threshold value in the comparing step, the step of growing a silicon carbide single crystal is performed at least one or more times.
    Type: Grant
    Filed: August 4, 2015
    Date of Patent: January 2, 2018
    Assignee: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Shin Harada, Tsutomu Hori
  • Patent number: 9845549
    Abstract: A crucible having a top surface, a bottom surface opposite to the top surface, and a tubular side surface located between the top surface and the bottom surface, a resistive heater provided outside of the crucible and made of carbon, a source material provided in the crucible, and a seed crystal provided to face the source material in the crucible are prepared. A silicon carbide single crystal is grown on the seed crystal by sublimating the source material with the resistive heater. In the step of growing a silicon carbide single crystal, a value obtained by dividing a value of a current flowing through the resistive heater by a cross-sectional area of the resistive heater perpendicular to a direction in which the current flows is maintained at 5 A/mm2 or less.
    Type: Grant
    Filed: July 21, 2015
    Date of Patent: December 19, 2017
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Shin Harada, Tsutomu Hori
  • Publication number: 20170335486
    Abstract: A crystal growth apparatus includes: a chamber including a gas inlet, a gas outlet, a welded portion, and a water-cooling portion configured to water-cool a portion at least including the welded portion; an exhaust pump connected to the gas outlet; a dew point instrument disposed between the gas outlet and the exhaust pump, the dew point instrument being configured to measure a dew point of gas passing through the gas outlet.
    Type: Application
    Filed: December 17, 2015
    Publication date: November 23, 2017
    Applicant: Sumitomo Electric Industries, Ltd.
    Inventors: Shin HARADA, Tsutomu HORI, Sho SASAKI, Tetsuya KISHIDA
  • Publication number: 20170335487
    Abstract: A method for manufacturing a silicon carbide single crystal includes: packing a silicon carbide source material into a crucible, the silicon carbide source material having a flowability index of not less than 70 and not more than 100; and sublimating the silicon carbide source material by heating the silicon carbide source material.
    Type: Application
    Filed: January 5, 2016
    Publication date: November 23, 2017
    Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Sho SASAKI, Shin HARADA, Tsutomu HORI
  • Publication number: 20170314161
    Abstract: A crucible having a tubular inner surface is prepared. A source material is arranged so as to make contact with the inner surface, and a seed crystal is arranged in the crucible so as to face the source material. A silicon carbide single crystal grows on the seed crystal by sublimation of the source material. The inner surface is formed of a first region surrounding the source material and a second region other than the first region. In the growing a silicon carbide single crystal, an amount of heat per unit area in the first region is smaller than an amount of heat per unit area in the second region.
    Type: Application
    Filed: November 18, 2015
    Publication date: November 2, 2017
    Applicant: Sumitomo Electric Industries, Ltd.
    Inventors: Sho SASAKI, Eiryo TAKASUKA, Shin HARADA, Tsutomu HORI
  • Patent number: 9799735
    Abstract: Quality of a silicon carbide single crystal is improved. A crucible having first and second sides is prepared. A solid source material for growing silicon carbide with a sublimation method is arranged on the first side. A seed crystal made of silicon carbide is arranged on the second side. The crucible is arranged in a heat insulating container. The heat insulating container has an opening facing the second side. The crucible is heated such that the solid source material sublimes. A temperature on the second side is measured through the opening in the heat insulating container. The opening has a tapered inner surface narrowed toward the outside of the heat insulating container.
    Type: Grant
    Filed: February 5, 2016
    Date of Patent: October 24, 2017
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Tsubasa Honke, Kyoko Okita, Tomohiro Kawase, Tsutomu Hori
  • Publication number: 20170288025
    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: Application
    Filed: July 4, 2016
    Publication date: October 5, 2017
    Applicant: Sumitomo Electric Industries, Ltd.
    Inventors: Tsutomu Hori, Hironori Itoh
  • Patent number: 9777400
    Abstract: A method for producing a single crystal includes a step of placing a source material powder and a seed crystal within a crucible, and a step of growing a single crystal on the seed crystal. The crucible includes a peripheral wall part and a bottom part and a lid part that are connected to the peripheral wall part to close the openings of the peripheral wall part, the lid part having a holder that holds the seed crystal. The bottom part has a connection region connected to the peripheral wall part and a thick region that is thicker than the connection region and that surrounds a central axis passing through a center of gravity of orthogonal projection of the bottom part, the orthogonal projection being formed on a plane perpendicular to a growth direction of the single crystal, the central axis extending in the growth direction of the single crystal.
    Type: Grant
    Filed: July 24, 2015
    Date of Patent: October 3, 2017
    Assignee: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Shunsaku Ueta, Tsutomu Hori, Akira Matsushima
  • Patent number: 9777401
    Abstract: A method for producing a single crystal includes a step of placing a source material powder and a seed crystal within a crucible; and a step of growing a single crystal on the seed crystal. The crucible includes a peripheral wall part and a bottom part and a lid part that are connected to the peripheral wall part to close the openings of the peripheral wall part. In the step of growing the single crystal on the seed crystal, the crucible is disposed on a spacer so as to form a space starting directly below an outer surface of the bottom part, and the peripheral wall part and an auxiliary heating member that is placed so as to face the outer surface of the bottom part with the space therebetween are heated by induction heating to sublime the source material powder to cause recrystallization on the seed crystal.
    Type: Grant
    Filed: August 5, 2015
    Date of Patent: October 3, 2017
    Assignee: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Shunsaku Ueta, Tsutomu Hori, Akira Matsushima
  • Publication number: 20170152609
    Abstract: A method of manufacturing a silicon carbide substrate has the following steps. A silicon carbide source material is partially sublimated. After partially sublimating the silicon carbide source material, a seed substrate having a main surface is placed in a growth container. By sublimating the remainder of the silicon carbide source material in the growth container, a silicon carbide crystal grows on the main surface of the seed substrate. In this way, an increase of dislocations in the main surface of the seed substrate can be suppressed, thereby providing a method of manufacturing a silicon carbide substrate having few dislocations.
    Type: Application
    Filed: February 14, 2017
    Publication date: June 1, 2017
    Inventors: Shinsuke FUJIWARA, Taro NISHIGUCHI, Tsutomu HORI, Naoki OOI, Shunsaku UETA
  • Patent number: 9631296
    Abstract: A method of manufacturing a silicon carbide substrate has the following steps. A silicon carbide source material is partially sublimated. After partially sublimating the silicon carbide source material, a seed substrate having a main surface is placed in a growth container. By sublimating the remainder of the silicon carbide source material in the growth container, a silicon carbide crystal grows on the main surface of the seed substrate. In this way, an increase of dislocations in the main surface of the seed substrate can be suppressed, thereby providing a method of manufacturing a silicon carbide substrate having few dislocations.
    Type: Grant
    Filed: June 11, 2013
    Date of Patent: April 25, 2017
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Shinsuke Fujiwara, Taro Nishiguchi, Tsutomu Hori, Naoki Ooi, Shunsaku Ueta
  • Patent number: 9546437
    Abstract: An ingot in which generation of crack is sufficiently suppressed is obtained. The ingot includes: a seed substrate formed of silicon carbide; and a silicon carbide layer grown on the seed substrate and containing nitrogen atoms. The silicon carbide layer has a thickness of 15 mm or more in a growth direction. In the silicon carbide layer, a concentration gradient of the nitrogen atoms in the growth direction is 5×1017 atoms/cm4 or less.
    Type: Grant
    Filed: February 5, 2014
    Date of Patent: January 17, 2017
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Tsutomu Hori, Makoto Sasaki, Tomohiro Kawase
  • Publication number: 20160340796
    Abstract: Provided is a method for manufacturing a silicon carbide single crystal capable of easily separating a silicon carbide single crystal from a pedestal. The method includes the step of fixing a seed substrate to a pedestal with a stress buffer layer being interposed therebetween, the step of growing a silicon carbide single crystal on the seed substrate, the step of separating the silicon carbide single crystal from the pedestal at the stress buffer layer, and the step of removing a residue of the stress buffer layer adhering to the silicon carbide single crystal subjected to the step of separating.
    Type: Application
    Filed: November 21, 2014
    Publication date: November 24, 2016
    Inventors: Tsutomu HORI, Shunsaku UETA, Akira MATSUSHIMA
  • Publication number: 20160236375
    Abstract: A silicon carbide ingot includes an end surface and an end surface opposite to the end surface. In the silicon carbide ingot, the end surface and the end surface face each other in a growth direction, and a gradient of a nitrogen concentration in the growth direction is not less than 1×1016 cm?4 and not more than 1×1018 cm?4.
    Type: Application
    Filed: October 14, 2014
    Publication date: August 18, 2016
    Inventors: Tsutomu HORI, Makoto SASAKI, Tsubasa HONKE, Tomohiro KAWASE
  • Publication number: 20160155808
    Abstract: Quality of a silicon carbide single crystal is improved. A crucible having first and second sides is prepared. A solid source material for growing silicon carbide with a sublimation method is arranged on the first side. A seed crystal made of silicon carbide is arranged on the second side. The crucible is arranged in a heat insulating container. The heat insulating container has an opening facing the second side. The crucible is heated such that the solid source material sublimes. A temperature on the second side is measured through the opening in the heat insulating container. The opening has a tapered inner surface narrowed toward the outside of the heat insulating container.
    Type: Application
    Filed: February 5, 2016
    Publication date: June 2, 2016
    Inventors: Tsubasa HONKE, Kyoko OKITA, Tomohiro KAWASE, Tsutomu HORI
  • Publication number: 20160138187
    Abstract: A method of manufacturing a silicon carbide single crystal includes steps of preparing a crucible, a source material disposed toward a bottom surface in the crucible, a seed crystal disposed to face the source material toward a top surface in the crucible, a resistive heater, and a heat insulator configured to be able to accommodate the crucible therein, measuring a mass of at least a portion of the heat insulator, comparing a measured value of the mass obtained in the measuring step with a threshold value, and growing a silicon carbide single crystal on the seed crystal by sublimation of the source material by heating the crucible placed in the heat insulator with the resistive heater. When the measured value of the mass is lower than the threshold value in the comparing step, the step of growing a silicon carbide single crystal is performed at least one or more times.
    Type: Application
    Filed: August 4, 2015
    Publication date: May 19, 2016
    Inventors: Shin HARADA, Tsutomu HORI
  • Publication number: 20160138185
    Abstract: A device for manufacturing a silicon carbide single crystal is prepared. The device includes a first resistive heater, a heat insulator, and a chamber. The heat insulator is provided with a first opening in a position facing the first resistive heater. The chamber is provided with a second opening in communication with the first opening. The first resistive heater has a first slit extending from an upper end surface toward a lower end surface of the first resistive heater and a second slit extending from the lower end surface toward the upper end surface, the first and second slits being alternately arranged along a circumferential direction, and the first resistive heater is provided with a third opening penetrating the first resistive heater and being in communication with the first and second openings.
    Type: Application
    Filed: October 7, 2015
    Publication date: May 19, 2016
    Inventors: Tsutomu HORI, Shin HARADA
  • Publication number: 20160138186
    Abstract: A method of manufacturing a silicon carbide single-crystal substrate includes the following steps. A seed crystal having a main surface and being made of silicon carbide, and a silicon carbide source material are prepared. A silicon carbide single crystal is grown on the main surface by sublimating the silicon carbide source material while maintaining a temperature gradient between any two points in the silicon carbide source material at 30° C./cm or less. The main surface of the seed crystal is a {0001} plane or a plane having an off angle of 10° or less relative to the {0001} plane, and the main surface has a screw dislocation density of 20/cm2 or more. Thus, a silicon carbide single-crystal substrate capable of achieving improved crystal quality and a method of manufacturing the same are provided.
    Type: Application
    Filed: May 14, 2014
    Publication date: May 19, 2016
    Inventors: Tsutomu HORI, Tomohiro KAWASE, Makoto SASAKI
  • Publication number: 20160122903
    Abstract: A device of manufacturing a silicon carbide single crystal includes a crucible, a first resistive heater, a second resistive heater, and a first support portion. The crucible has a top surface, a bottom surface opposite to the top surface, and a tubular side surface located between the top surface and the bottom surface. The first resistive heater is disposed to face the bottom surface. The second resistive heater is provided to surround the side surface. The first support portion supports the crucible such that the bottom surface is separated from the first resistive heater, and the side surface is separated from the second resistive heater. The first support portion is in contact with at least one of the top surface and the side surface.
    Type: Application
    Filed: August 25, 2015
    Publication date: May 5, 2016
    Inventors: Tsutomu HORI, Shin HARADA