Patents by Inventor Kazuhito Kamei

Kazuhito Kamei 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).

  • Patent number: 10450671
    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: Grant
    Filed: August 27, 2014
    Date of Patent: October 22, 2019
    Assignees: TOYOTA JIDOSHA KABUSHIKI KAISHA, NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Hironori Daikoku, Motohisa Kado, Kazuhito Kamei, Kazuhiko Kusunoki
  • Publication number: 20190229103
    Abstract: A semiconductor device includes: a first switching element that is provided on a high side; a first diode element that is connected in parallel to the first switching element; a second switching element that is provide on a low side and connected in series to the first switching element; and a second diode element that is connected in parallel to the second switching element, wherein the first switching element and one of the first diode element and the second diode element are stacked adjacently to each other in a vertical direction of respective electrode surfaces thereof via a conductive electrode, the second switching element and the other of the first diode element and the second diode element that is different from the diode element adjacent to the first switching element are stacked adjacently to each other in a vertical direction of respective electrode surfaces thereof via a conductive electrode, and the first switching element and the second switching element are not adjacent in a vertical direction
    Type: Application
    Filed: January 25, 2019
    Publication date: July 25, 2019
    Applicants: WASEDA UNIVERSITY, MITSUI HIGH-TEC., INC., TOYOTA JIDOSHA KABUSHIKI KAISHA
    Inventors: Kohei TATSUMI, Kazuhito KAMEI, Rikiya Kamimura, Koji SHIMIZU, Kazutoshi UEDA, Nobuaki SATO, Keiji TODA, Masayuki HIKITA, Akihiro IMAKIIRE
  • Patent number: 10145025
    Abstract: Provided is a method for producing a SiC single crystal which can suppress generation of SiC polycrystals. The method according to the present embodiment is in accordance with a solution growth method. The method for producing a SiC single crystal according to the present embodiment comprises a power-output increasing step, a contact step, and a growth step. In the power-output increasing step, high-frequency power output of an induction heating device is increased to crystal-growth high-frequency power output. In the contact step, a SiC seed crystal is brought into contact with a Si—C solution. The high-frequency power output of the induction heating device in the contact step is more than 80% of the crystal-growth high-frequency power output. The temperature of the Si—C solution in the contact step is less than a crystal growth temperature. In the growth step, the SiC single crystal is grown at the crystal growth temperature.
    Type: Grant
    Filed: March 16, 2016
    Date of Patent: December 4, 2018
    Assignee: TOYOTA JIDOSHA KABUSHIKI KAISHA
    Inventors: Kazuaki Seki, Kazuhiko Kusunoki, Kazuhito Kamei, Katsunori Danno, Hironori Daikoku, Masayoshi Doi
  • Patent number: 10119199
    Abstract: A production method according an embodiment of the present invention is to produce a SiC single crystal by a solution growth technique, and includes a formation step and a growth step. In the formation step, material of Si—C solution contained in a crucible is melted, and a Si—C solution is formed. In the growth step, a SiC seed crystal attached to a bottom end of a seed shaft is brought into contact with the Si—C solution, and a SiC single crystal is grown on a crystal growth surface of the SiC seed crystal. In the growth step, while a temperature of the Si—C solution is being raised, the SiC single crystal is grown. The SiC single crystal production method according to the embodiment facilitates production of a SiC single crystal of a desired polytype.
    Type: Grant
    Filed: March 17, 2016
    Date of Patent: November 6, 2018
    Assignee: TOYOTA JIDOSHA KABUSHIKI KAISHA
    Inventors: Kazuaki Seki, Kazuhito Kamei, Kazuhiko Kusunoki, Katsunori Danno, Hironori Daikoku, Masayoshi Doi
  • Patent number: 10100432
    Abstract: An apparatus (10) for producing an SiC single crystal is used in the solution growth includes a seed shaft (28) and a crucible (14). The seed shaft (28) has a lower end surface (28S) to which an SiC seed crystal (32) is to be attached. The crucible (14) holds an Si—C solution (15). The seed shaft (28) includes a cylinder part (28A), a bottom part (28B), and a low heat conductive member (28C). The bottom part (28B) is located at the lower end of the cylinder part (28A) and has the lower end surface (28S). The low heat conductive member (28C) is arranged on the upper surface of the bottom part (28B) and has a thermal conductivity lower than that of the bottom part (28B). This production apparatus can make the temperature within the crystal growth surface of the SiC seed crystal less liable to vary.
    Type: Grant
    Filed: July 10, 2013
    Date of Patent: October 16, 2018
    Assignee: TOYOTA JIDOSHA KABUSHIKI KAISHA
    Inventors: Nobuhiro Okada, Kazuhito Kamei, Kazuhiko Kusunoki, Nobuyoshi Yashiro, Koji Moriguchi, Hironori Daikoku, Motohisa Kado, Hidemitsu Sakamoto
  • Patent number: 10066316
    Abstract: The present invention provides a method of raising the rate of reduction of the dislocation density accompanying growth of an SiC single crystal to counter the increase in the threading screw dislocations formed near the interface of the seed crystal and grown SiC single crystal and thereby produce an SiC single-crystal ingot with a small threading screw dislocation density from the initial stage of growth.
    Type: Grant
    Filed: February 18, 2016
    Date of Patent: September 4, 2018
    Assignee: SHOWA DENKO K.K.
    Inventors: Komomo Tani, Takayuki Yano, Tatsuo Fujimoto, Hiroshi Tsuge, Kazuhito Kamei, Kazuhiko Kusunoki, Kazuaki Seki
  • Patent number: 9982365
    Abstract: Provided is a method for producing a SiC single crystal wherein generation of polycrystals can be inhibited even if the temperature of the Si—C solution is changed after seed touching.
    Type: Grant
    Filed: November 14, 2014
    Date of Patent: May 29, 2018
    Assignees: TOYOTA JIDOSHA KABUSHIKI KAISHA, NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Katsunori Danno, Kazuhiko Kusunoki, Kazuhito Kamei
  • Publication number: 20180112328
    Abstract: A production method according an embodiment of the present invention is to produce a SiC single crystal by a solution growth technique, and includes a formation step and a growth step. In the formation step, material of Si—C solution contained in a crucible is melted, and a Si—C solution is formed. In the growth step, a SiC seed crystal attached to a bottom end of a seed shaft is brought into contact with the Si—C solution, and a SiC single crystal is grown on a crystal growth surface of the SiC seed crystal. In the growth step, while a temperature of the Si—C solution is being raised, the SiC single crystal is grown. The SiC single crystal production method according to the embodiment facilitates production of a SiC single crystal of a desired polytype.
    Type: Application
    Filed: March 17, 2016
    Publication date: April 26, 2018
    Inventors: Kazuaki SEKI, Kazuhito KAMEI, Kazuhiko KUSUNOKI, Katsunori DANNO, Hironori DAIKOKU, Masayoshi DOI
  • Publication number: 20180112329
    Abstract: Provided is a method for producing a SiC single crystal which can suppress generation of SiC polycrystals. The method according to the present embodiment is in accordance with a solution growth method. The method for producing a SiC single crystal according to the present embodiment comprises a power-output increasing step, a contact step, and a growth step. In the power-output increasing step, high-frequency power output of an induction heating device is increased to crystal-growth high-frequency power output. In the contact step, a SiC seed crystal is brought into contact with a Si—C solution. The high-frequency power output of the induction heating device in the contact step is more than 80% of the crystal-growth high-frequency power output. The temperature of the Si—C solution in the contact step is less than a crystal growth temperature. In the growth step, the SiC single crystal is grown at the crystal growth temperature.
    Type: Application
    Filed: March 16, 2016
    Publication date: April 26, 2018
    Inventors: Kazuaki SEKI, Kazuhiko KUSUNOKI, Kazuhito KAMEI, Katsunori DANNO, Hironori DAIKOKU, Masayoshi DOI
  • Patent number: 9920449
    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: Grant
    Filed: February 12, 2015
    Date of Patent: March 20, 2018
    Assignee: TOYOTA JIDOSHA KABUSHIKI KAISHA
    Inventors: Kazuhiko Kusunoki, Kazuhito Kamei, Hironori Daikoku, Hidemitsu Sakamoto
  • Publication number: 20180066380
    Abstract: The present invention provides a method of raising the rate of reduction of the dislocation density accompanying growth of an SiC single crystal to counter the increase in the threading screw dislocations formed near the interface of the seed crystal and grown SiC single crystal and thereby produce an SiC single-crystal ingot with a small threading screw dislocation density from the initial stage of growth.
    Type: Application
    Filed: February 18, 2016
    Publication date: March 8, 2018
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Komomo TANI, Takayuki YANO, Tatsuo FUJIMOTO, Hiroshi TSUGE, Kazuhito KAMEI, Kazuhiko KUSUNOKI, Kazuaki SEKI
  • Patent number: 9896778
    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: Grant
    Filed: May 19, 2014
    Date of Patent: February 20, 2018
    Assignee: TOYOTA JIDOSHA KABUSHIKI KAISHA
    Inventors: Kazuhito Kamei, Kazuhiko Kusunoki, Motohisa Kado, Hironori Daikoku, Hidemitsu Sakamoto
  • Patent number: 9822468
    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: Grant
    Filed: May 3, 2016
    Date of Patent: November 21, 2017
    Assignees: TOYOTA JIDOSHA KABUSHIKI KAISHA, NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Hironori Daikoku, Kazuhito Kamei, Kazuhiko Kusunoki, Kazuaki Seki, Yutaka Kishida
  • Publication number: 20170306522
    Abstract: An object of the present invention is to provide a SIC single crystal production apparatus that stirs and heats a Si—C solution easily. The apparatus includes a crucible capable of containing a Si—C solution, a seed shaft, and an induction heater. The crucible includes a tubular portion and a bottom portion. The tubular portion includes an outer peripheral surface and an inner peripheral surface. The bottom portion is disposed at a lower end of the tubular portion. The bottom portion defines an inner bottom surface of the crucible. The outer peripheral surface includes a groove extending in a direction crossing the circumferential direction of the tubular portion.
    Type: Application
    Filed: October 13, 2015
    Publication date: October 26, 2017
    Applicants: NIPPON STEEL & SUMITOMO METAL CORPORATION, TOYOTA JIDOSHA KABUSHIKI KAISHA
    Inventors: Kazuhito KAMEI, Yutaka KISHIDA, Kazuhiko KUSUNOKI, Hironori DAIKOKU, Masayoshi DOI
  • 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
  • Publication number: 20170283982
    Abstract: A production method according to an embodiment includes a formation step (S1), a first growth step (S2), a recovery step (S3), and a second growth step (S4). In the formation step (S1), a Si—C solution containing Si, Al and C is formed in a crucible. In the first growth step (S2), a seed shaft is moved down to bring a SiC seed crystal attached to the bottom edge of the seed shaft onto contact with the Si—C solution, and thereafter, an Al-doped p-type SiC single crystal is grown on the SiC seed crystal. After the first growth step (S2), the Al concentration in the Si—C solution is increased in the recovery step (S3). After the recovery step (S3), the Al-doped p-type SiC single crystal is further grown in the second growth step (S4).
    Type: Application
    Filed: August 31, 2015
    Publication date: October 5, 2017
    Inventors: Kazuhiko KUSUNOKI, Kazuhito KAMEI, Kazuaki SEKI, Yutaka KISHIDA, Koji MORIGUCHI, Hiroshi KAIDO
  • 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: 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