Patents by Inventor Hironori Daikoku

Hironori Daikoku 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: 20170298533
    Abstract: The provided by the disclosure is a SiC single crystal production method permitting suppression of temperature variation of a Si—C solution even in a case of long-time crystal growth. The SiC single crystal production method includes: a preparation step of preparing a production apparatus including a crucible, a seed shaft, and an internal lid; a formation step of heating the material in the crucible to form the Si—C solution; a growth step of bringing the seed crystal into contact with the Si—C solution to produce the Si—C single crystal on the seed crystal; an internal lid adjustment step of vertically moving one of the internal lid and the crucible relative to the other during the growth step to keep an amount of variation in vertical distance between the internal lid and the Si—C solution within a first reference range.
    Type: Application
    Filed: October 13, 2015
    Publication date: October 19, 2017
    Inventors: Kazuhiko KUSUNOKI, Kazuhito KAMEI, Kazuaki SEKI, Yutaka KISHIDA, Koji MORIGUCHI, Hiroshi KAIDO, Hironori DAIKOKU, Masayoshi DOI
  • Patent number: 9783911
    Abstract: A production apparatus is used for a solution growth method. The production apparatus includes a seed shaft and a crucible. The seed shaft has a lower end surface to which an SiC seed crystal is attached. The crucible contains an SiC solution. The crucible includes a cylindrical portion, a bottom portion, and an inner lid. The bottom portion is disposed at a lower end of the cylindrical portion. The inner lid is disposed in the cylindrical portion. The inner lid has a through hole and is positioned below a liquid surface of the SiC solution when the SiC solution is contained in the crucible.
    Type: Grant
    Filed: July 15, 2013
    Date of Patent: October 10, 2017
    Assignee: TOYOTA JIDOSHA KABUSHIKI KAISHA
    Inventors: Nobuyoshi Yashiro, Kazuhito Kamei, Kazuhiko Kusunoki, Nobuhiro Okada, Koji Moriguchi, Hironori Daikoku, Hidemitsu Sakamoto, Motohisa Kado
  • Patent number: 9732441
    Abstract: An apparatus for producing an SiC single crystal includes a crucible for accommodating an Si—C solution and a seed shaft having a lower end surface where an SiC seed crystal (36) would be attached. The seed shaft includes an inner pipe that extends in a height direction of the crucible and has a first passage. An outer pipe accommodates the inner pipe and constitutes a second passage between itself and the inner pipe and has a bottom portion whose lower end surface covers a lower end opening of the outer pipe. One passage of the first and second passages serves as an introduction passage where coolant gas flows downward, and the other passage serves as a discharge passage where coolant gas flows upward. A region inside the pipe that constitutes the introduction passage is to be overlapped by a region of not less than 60% of the SiC seed crystal.
    Type: Grant
    Filed: June 15, 2012
    Date of Patent: August 15, 2017
    Assignees: NIPPON STEEL & SUMITOMO METAL CORPORATION, TOYOTA JIDOSHA KABUSHIKI KAISHA
    Inventors: Kazuhiko Kusunoki, Kazuhito Kamei, Nobuyoshi Yashiro, Nobuhiro Okada, Hironori Daikoku, Motohisa Kado, Hidemitsu Sakamoto
  • Publication number: 20170226658
    Abstract: A method and apparatus for manufacturing an SiC single crystal includes a graphite crucible for receiving an SiC solution with first and second induction heating coils wound around it. The first induction heating coil is located higher than the surface of the SiC solution. The second induction heating coil is located lower than the first induction heating coil. A power supply supplies a first alternating current to the first induction heating coil and supplies, to the second induction heating coil, a second alternating current having the same frequency as the first alternating current and flowing in the direction opposite to that of the first alternating current. The distance between the surface of the SiC solution and the position in the portion of the side wall of the crucible in contact with the SiC solution with the strength of a magnetic field at its maximum satisfies a predetermined equation.
    Type: Application
    Filed: October 7, 2015
    Publication date: August 10, 2017
    Applicants: Nippon Steel & Sumitomo Metal Corporation, Toyota Jidosha Kabushiki Kaisha
    Inventors: Yutaka KISHIDA, Kazuhito KAMEI, Hironori DAIKOKU, Masayoshi DOI
  • Patent number: 9708734
    Abstract: The purpose of the present invention is to produce a high-quality SiC single crystal with good reproducibility while avoiding the fluctuations in the solution-contacting position of a seed crystal among production operations. A method for producing a SiC single crystal by bringing a SiC seed crystal supported by a supporting bar into contact with a solution that has been heated by high-frequency induction to thereby grow the SiC single crystal, wherein the supporting bar is born down while applying a magnetic field to the solution to thereby bring the SiC seed crystal into contact with the solution, and subsequently the application of the magnetic field is halted to grow the SiC single crystal.
    Type: Grant
    Filed: November 11, 2013
    Date of Patent: July 18, 2017
    Assignee: TOYOTA JIDOSHA KABUSHIKI KAISHA
    Inventors: Hironori Daikoku, Hidemitsu Sakamoto, Motohisa Kado, Kazuhiko Kusunoki
  • Publication number: 20170198408
    Abstract: Provided is a method for producing a SiC single crystal having a concave growth surface and containing no inclusions, even when conducting large diameter crystal growth. This is achieved by a method for producing a SiC single crystal in which a seed crystal substrate held on a seed crystal holding shaft is contacted with a Si—C solution having a temperature gradient such that the temperature decreases from the interior toward the liquid level, to cause crystal growth of a SiC single crystal, wherein the seed crystal holding shaft has a shaft portion and a seed crystal holding portion at the bottom end of the shaft portion, and the ratio of the diameter D1 of the shaft portion to the diameter D2 of the seed crystal holding portion (D1/D2) is no greater than 0.28.
    Type: Application
    Filed: January 6, 2017
    Publication date: July 13, 2017
    Applicants: TOYOTA JIDOSHA KABUSHIKI KAISHA, NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Motohisa KADO, Hironori DAIKOKU, Kazuhiko KUSUNOKI, Kazuaki SEKI
  • Patent number: 9702056
    Abstract: A region of an SiC solution in the vicinity of an SiC seed crystal is cooled while suppressing the temperature variation in a peripheral region of the SiC solution. An apparatus includes a seed shaft and a crucible for an SiC solution. The seed shaft has a lower end surface for attachment to an SiC seed crystal. The crucible comprises a main body, an intermediate cover, and a top cover. The main body includes a first cylindrical portion and a bottom portion at a lower end portion of the first cylindrical portion. The intermediate cover is within the first cylindrical portion and above the liquid level of the SiC solution in the main body. The intermediate cover has a first through hole for the seed shaft. The top cover is disposed above the intermediate cover and has a second through hole for the seed shaft to pass through.
    Type: Grant
    Filed: June 11, 2012
    Date of Patent: July 11, 2017
    Assignees: NIPPON STEEL & SUMITOMO METAL CORPORATION, TOYOTA JIDOSHA KABUSHIKI KAISHA
    Inventors: Kazuhito Kamei, Kazuhiko Kusunoki, Nobuyoshi Yashiro, Nobuhiro Okada, Hironori Daikoku, Motohisa Kado, Hidemitsu Sakamoto
  • Patent number: 9631295
    Abstract: Provided is a method for producing SiC single crystals while maintaining a temperature gradient such that the temperature decreases from within an Si solution inside a graphite crucible toward the solution surface, with the SiC seed crystals that have contacted the solution surface serving as the starting point for crystal seed growth, wherein when the crystal growth surface of the SiC seed crystals, which serves as the starting point for SiC single crystal growth, contacts the solution surface, the height by which the solution rises to the side of the SiC seed crystals is within the range where the SiC single crystals that have grown from the crystal growth surface and the SiC single crystals that have grown from the side grow as one SiC single crystal unit.
    Type: Grant
    Filed: July 27, 2011
    Date of Patent: April 25, 2017
    Assignees: TOYOTA JIDOSHA KABUSHIKI KAISHA, NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Hironori Daikoku, Kazuhito Kamei
  • Patent number: 9624599
    Abstract: A SiC single crystal manufacturing method whereby growing speed improvement required to have high productivity can be achieved, while maintaining flat growth in which uniform single crystal growth can be continued at the time of growing a SiC single crystal using a solution method. In the method, a SiC single crystal is grown in a crucible from a Si solution containing C. The method includes alternately repeating: a high supersaturation degree growing period, in which the growth is promoted by maintaining the supersaturation degree of C in the Si solution higher than an upper limit critical value at which flat growth can be maintained, the supersaturation degree being at a growing interface between the Si solution and a SiC single crystal being grown; and a low supersaturation degree growing period, in which the growth is promoted by maintaining the supersaturation degree lower than the critical value.
    Type: Grant
    Filed: December 9, 2011
    Date of Patent: April 18, 2017
    Assignees: TOYOTA JIDOSHA KABUSHIKI KAISHA, NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Motohisa Kado, Hironori Daikoku, Kazuhiko Kusunoki
  • Patent number: 9617655
    Abstract: An apparatus for SIC single crystal has an induction heating control unit such that frequency f (Hz) of alternating current to the induction heating unit satisfies Formula (1); D1 (mm) is permeation depth of electromagnetic waves into a crucible side wall by the heating unit, D2 (mm) is permeation depth of electromagnetic waves into a SIC solution, T (mm) is thickness of the crucible side wall of the crucible, and R (mm) is crucible inner radius: (D1?T)×D2/R>1.5??(1) where, D1 is defined by Formula (2) and D2 by Formula (3): D1=503292×(1/(f×?c×?c))1/2??(2) D2=503292×(1/(f×?s×?s))1/2??(3); ?c is electric conductivity (S/m) of the sidewall, ?s is electric conductivity (S/m) of the SiC solution; ?c is relative permeability of the sidewall, and ?s is relative permeability of the SIC solution.
    Type: Grant
    Filed: December 26, 2011
    Date of Patent: April 11, 2017
    Assignees: NIPPON STEEL & SUMITOMO METAL CORPORATION, TOYOTA JIDOSHA KABUSHIKI KAISHA
    Inventors: Nobuhiro Okada, Kazuhito Kamei, Kazuhiko Kusunoki, Nobuyoshi Yashiro, Kouji Moriguchi, Hironori Daikoku, Hiroshi Suzuki, Tomokazu Ishii, Hidemitsu Sakamoto, Motohisa Kado, Yoichiro Kawai
  • Publication number: 20170009373
    Abstract: The production method of an SiC single crystal is a production method of an SiC single crystal by a solution growth process. The production method includes a contact step A, a contact step B, and a growth step. In the contact step A, a partial region of the principal surface is brought into contact with a stored Si—C solution. In the contact step B, a contact region between the principal surface and the stored Si—C solution expands, due to a wetting phenomenon, starting from an initial contact region which is the partial region brought into contact in the contact step A. In the growth step, an SiC single crystal is grown on the principal surface which is in contact with the stored Si—C solution.
    Type: Application
    Filed: February 12, 2015
    Publication date: January 12, 2017
    Inventors: Kazuhiko KUSUNOKI, Kazuhito KAMEI, Hironori DAIKOKU, Hidemitsu SAKAMOTO
  • Patent number: 9523156
    Abstract: Provided are: a high-quality SiC single crystal ingot that suppresses the generation of inclusions; and a production method for said SiC single crystal ingot. The present invention pertains to a SiC single crystal ingot including a seed crystal substrate and a SiC growth crystal grown using the solution method and using the seed crystal substrate as the origin thereof, the growth crystal having a recessed crystal growth surface and not including inclusions.
    Type: Grant
    Filed: May 8, 2013
    Date of Patent: December 20, 2016
    Assignees: TOYOTA JIDOSHA KABUSHIKI KAISHA, NIPPON STEEL & SUMITOMO METAL CORPORATIN
    Inventors: Motohisa Kado, Hironori Daikoku, Hidemitsu Sakamoto, Kazuhiko Kusunoki, Nobuhiro Okada
  • Patent number: 9512540
    Abstract: A method for manufacturing an n-type SiC single crystal, enables the suppression of the variation in nitrogen concentration among a plurality of n-type SiC single crystal ingots manufactured. A method includes the steps of: providing a manufacturing apparatus (100) including a chamber (1) having an area in which a crucible (7) is to be disposed; heating the area in which the crucible (7) is to be disposed and evacuating the gas in the chamber (1); filling, after the evacuation, the chamber (1) with a mixed gas containing a noble gas and nitrogen gas; heating and melting a starting material housed in the crucible (7) disposed in the area to produce a SiC solution (8) containing silicon and carbon; and immersing a SiC seed crystal into the SiC solution under the mixed gas atmosphere to grow an n-type SiC single crystal on the SiC seed crystal.
    Type: Grant
    Filed: November 4, 2011
    Date of Patent: December 6, 2016
    Assignees: NIPPON STEEL & SUMITOMO METAL CORPORATION, TOYOTA JIDOSHA KABUSHIKI KAISHA
    Inventors: Kazuhiko Kusunoki, Kazuhito Kamei, Nobuyoshi Yashiro, Kouji Moriguchi, Nobuhiro Okada, Katsunori Danno, Hironori Daikoku
  • Publication number: 20160340794
    Abstract: A method for producing a SiC single crystal by a solution process is provided, which allows generation of miscellaneous crystals to be reduced. Method for producing a SiC single crystal wherein a crucible has thickness Lu in horizontal direction at same height as liquid level of Si—C solution, and thickness Ld in horizontal direction at same height as bottom inner wall, Ld/Lu is 2.00 to 4.21, and thickness in horizontal direction of crucible monotonously increases between Lu and Ld from Lu toward Ld, wall thickness of crucible is 1 mm or greater, bottom thickness Lb in vertical direction of crucible is between 1 mm and 15 mm, bottom outer wall of crucible has flat section with area of 100 mm2 or greater, depth of Si—C solution from bottom inner wall is 30 mm or greater, and method includes heating and electromagnetic stirring Si—C solution with high-frequency coil.
    Type: Application
    Filed: May 3, 2016
    Publication date: November 24, 2016
    Applicants: TOYOTA JIDOSHA KABUSHIKI KAISHA, NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Hironori DAIKOKU, Kazuhito KAMEI, Kazuhiko KUSUNOKI, Kazuaki SEKI, Yutaka KISHIDA
  • Publication number: 20160237590
    Abstract: Provided is a SiC single crystal that has a large growth thickness and contains no inclusions. A SiC single crystal grown by a solution process, wherein the total length M of the outer peripheral section formed by the {1-100} faces on the {0001} growth surface of the SiC single crystal, and the length P of the outer periphery of the growth surface of the SiC single crystal, satisfy the relationship M/P?0.70, and the length in the growth direction of the SiC single crystal is 2 mm or greater.
    Type: Application
    Filed: August 27, 2014
    Publication date: August 18, 2016
    Applicants: TOYOTA JIDOSHA KABUSHIKI KAISHA, NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Hironori DAIKOKU, Motohisa KADO, Kazuhito KAMEI, Kazuhiko KUSUNOKI
  • Patent number: 9388508
    Abstract: A manufacturing apparatus of a SiC single crystal which can suppress the generation of a polycrystal is provided. A jig (41) and a crucible (6) are accommodated in a chamber (1). A SiC solution (8) is housed in the crucible (6). The jig (41) includes a seed shaft (411) and a cover member (412). The seed shaft (411) can move up and down, and a SiC seed crystal (9) is attached to the lower surface thereof. The cover member (412) is attached to the lower end portion of the seed shaft (411). The cover member (412) is a housing which has an opening at its lower end, wherein the lower end portion of the seed shaft (411) is disposed in the cover member (412).
    Type: Grant
    Filed: December 26, 2011
    Date of Patent: July 12, 2016
    Assignee: TOYOTA JIDOSHA KABUSHIKI KAISHA
    Inventors: Kazuhito Kamei, Kazuhiko Kusunoki, Nobuyoshi Yashiro, Nobuhiro Okada, Motohisa Kado, Hidemitsu Sakamoto, Hironori Daikoku
  • Publication number: 20160122900
    Abstract: An apparatus for producing SiC single crystals where the quality of the SiC single crystals is improved, and a production method using such an apparatus are provided. The apparatus for producing SiC single crystals according to an embodiment of the present invention is employed to produce an SiC single crystal by the solution growth method. The production apparatus includes a crucible and a support shaft. The crucible accommodates an Si—C solution. The support shaft supports the crucible. The support shaft includes a heat removing portion for removing heat from a bottom portion of the crucible. The heat removing portion includes one of (a) a contact portion having a thermal conductivity not less than that of the bottom portion and contacting at least a portion of the bottom portion and (b) a space adjacent to at least a portion of the contact portion or the bottom portion.
    Type: Application
    Filed: May 19, 2014
    Publication date: May 5, 2016
    Applicants: NIPPON STEEL & SUMITOMO METAL CORPORATION, TOYOTA JIDOSHA KABUSHIKI KAISHA
    Inventors: Kazuhito KAMEI, Kazuhiko KUSUNOKI, Motohisa KADO, Hironori DAIKOKU, Hidemitsu SAKAMOTO
  • Publication number: 20160090664
    Abstract: A method for producing a SiC single crystal by a solution process, comprising contacting a seed crystal substrate held on a seed crystal holding shaft with a Si—C solution to conduct crystal growth of a SiC single crystal, the Si—C solution being housed in a crucible and having a temperature gradient in which the temperature decreases from the interior toward the surface, wherein a high-frequency coil is disposed around the side sections of the crucible, and the crucible has a multilayer structure including an inner crucible, and one or more outer crucibles disposed surrounding the inner crucible, and wherein the method comprises moving the inner crucible alone in the vertical upward direction so as to minimize changes in the relative position of the liquid level of the Si—C solution and the center section of the high-frequency coil in the vertical direction during the crystal growth of the SiC single crystal.
    Type: Application
    Filed: September 15, 2015
    Publication date: March 31, 2016
    Inventors: Katsunori DANNO, Hironori DAIKOKU, Masayoshi DOI, Kazuhiko KUSUNOKI
  • Publication number: 20160053402
    Abstract: The present invention provides a method for producing a SiC single crystal, which allows improving the quality of the single crystal even when crystal growth is performed by forming a meniscus. A growth step in the production method according to the present embodiment comprises a forming step and a first maintenance step. In the forming step, a meniscus is formed between a growth interface of a SiC single crystal and a liquid surface of a Si—C solution. In the first maintenance step, the fluctuation range of the height of the meniscus is maintained within a predetermined range by moving at least one of a seed shaft and a crucible relative to the other in the height direction.
    Type: Application
    Filed: April 9, 2014
    Publication date: February 25, 2016
    Inventors: Kazuhiko KUSUNOKI, Kazuhito KAMEI, Hironori DAIKOKU, Hidemitsu SAKAMOTO, Motohisa KADO
  • Publication number: 20150299900
    Abstract: The purpose of the present invention is to produce a high-quality SiC single crystal with good reproducibility while avoiding the fluctuations in the solution-contacting position of a seed crystal among production operations. A method for producing a SiC single crystal by bringing a SiC seed crystal supported by a supporting bar into contact with a solution that has been heated by high-frequency induction to thereby grow the SiC single crystal, wherein the supporting bar is born down while applying a magnetic field to the solution to thereby bring the SiC seed crystal into contact with the solution, and subsequently the application of the magnetic field is halted to grow the SiC single crystal.
    Type: Application
    Filed: November 11, 2013
    Publication date: October 22, 2015
    Applicant: TOYOTA JIDOSHA KABUSHIKI KAISHA
    Inventors: Hironori DAIKOKU, Hidemitsu SAKAMOTO, Motohisa KADO, Kazuhiko KUSUNOKI