Patents by Inventor Akinori Koukitu

Akinori Koukitu 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: 11047067
    Abstract: [Problem] To provide a crystal laminate structure having a ?-Ga2O3 based single crystal film in which a dopant is included throughout the crystal and the concentration of the dopant can be set across a broad range. [Solution] In one embodiment of the present invention, provided is a crystal laminate structure 1 which includes: a Ga2O3 based substrate 10; and a ?-Ga2O3 based single crystal film 12 formed by epitaxial crystal growth on a primary face 11 of the Ga2O3 based substrate 10 and including Cl and a dopant doped in parallel with the crystal growth at a concentration of 1×1013 to 5.0×1020 atoms/cm3.
    Type: Grant
    Filed: December 3, 2019
    Date of Patent: June 29, 2021
    Assignees: TAMURA CORPORATION, NATIONAL UNIVERSITY CORPORATION TOKYO UNIVERSITY OF AGRICULTURE AND TECHNOLOGY
    Inventors: Ken Goto, Akinori Koukitu, Yoshinao Kumagai, Hisashi Murakami
  • Publication number: 20210172061
    Abstract: A method for producing a GaN crystal that includes: (i) a seed crystal preparation step of preparing a GaN seed crystal having one or more facets selected from a {10-10} facet and a {10-1-1} facet; and (ii) a growth step of growing GaN from vapor phase on a surface comprising the one or more facets of the GaN seed crystal using GaCl3 and NH3 as raw materials.
    Type: Application
    Filed: February 18, 2021
    Publication date: June 10, 2021
    Applicants: MITSUBISHI CHEMICAL CORPORATION, NATIONAL UNIVERSITY CORPORATION TOKYO UNIVERSITY OF AGRICULTURE AND TECHNOLOGY
    Inventors: Kenji ISO, Akinori KOUKITU, Hisashi MURAKAMI
  • Patent number: 10961619
    Abstract: The present invention provides a novel method for producing a GaN crystal, the method including growing GaN from vapor phase on a semi-polar or non-polar GaN surface using GaCl3 and NH3 as raw materials. Provided herein is an invention of a method for producing a GaN crystal, including the steps of: (i) preparing a GaN seed crystal having a non-polar or semi-polar surface whose normal direction forms an angle of 85° or more and less than 170° with a [0001] direction of the GaN seed crystal; and (ii) growing GaN from vapor phase on a surface including the non-polar or semi-polar surface of the GaN seed crystal using GaCl3 and NH3 as raw materials.
    Type: Grant
    Filed: September 13, 2018
    Date of Patent: March 30, 2021
    Assignees: MITSUBISHI CHEMICAL CORPORATION, NATIONAL UNIVERSITY CORPORATION TOKYO UNIVERSITY OF AGRICULTURE AND TECHNOLOGY
    Inventors: Kenji Iso, Akinori Koukitu, Hisashi Murakami
  • Patent number: 10861945
    Abstract: A semiconductor element includes a high-resistivity substrate that includes a ?-Ga2O3-based single crystal including an acceptor impurity, a buffer layer on the high-resistivity substrate, the buffer layer including a ?-Ga2O3-based single crystal, and a channel layer on the buffer layer, the channel layer including a ?-Ga2O3-based single crystal including a donor impurity. A crystalline laminate structure includes a high-resistivity substrate that includes a ?-Ga2O3-based single crystal including an acceptor impurity, a buffer layer on the high-resistivity substrate, the buffer layer including a ?-Ga2O3-based single crystal, and a donor impurity-containing layer on the buffer layer, the donor impurity-containing layer including a ?-Ga2O3-based single crystal including a donor impurity.
    Type: Grant
    Filed: August 18, 2015
    Date of Patent: December 8, 2020
    Assignees: TAMURA CORPORATION, NATIONAL INSTITUTE OF INFORMATION AND COMMUNICATIONS TECHNOLOGY, NATIONAL UNIVERSITY CORPORATION TOKYO UNIVERSITY OF AGRICULTURE AND TECHNOLOGY
    Inventors: Kohei Sasaki, Ken Goto, Masataka Higashiwaki, Man Hoi Wong, Akinori Koukitu, Yoshinao Kumagai, Hisashi Murakami
  • Publication number: 20200255974
    Abstract: A method of manufacturing a crystalline gallium nitride film, including: a growth step in which a GaCl3 gas, a halogen gas, an NH3 gas, and a carrier gas consisting of one or more inert gases are supplied onto a substrate, thereby growing a crystalline gallium nitride film on the substrate, wherein a partial pressure ratio [PHalogen/PGaCl3] is defined as a ratio of a partial pressure of the halogen gas with respect to a partial pressure of the GaCl3 gas on the substrate in the growth step, and the partial pressure ratio [PHalogen/PGaCl3] is 0.20 or more.
    Type: Application
    Filed: September 13, 2018
    Publication date: August 13, 2020
    Applicants: National University Corporation Tokyo University of Agriculture and Technology, Taiyo Nippon Sanso Corporation
    Inventors: Akinori Koukitu, Hisashi Murakami, Akira Yamaguchi
  • Patent number: 10676841
    Abstract: A semiconductor substrate for being used as a base substrate for epitaxial crystal growth by HVPE method includes a ?-Ga2O3-based single crystal, and a principal surface that is a plane parallel to a [010] axis of the ?-Ga2O3-based single crystal. An epitaxial wafer includes the semiconductor substrate, and an epitaxial layer that includes a ?-Ga2O3-based single crystal and is formed on the principal surface of the semiconductor substrate by epitaxial crystal growth using the HVPE method. A method for manufacturing the epitaxial wafer includes forming the epitaxial layer by epitaxial crystal growth using the HVPE method on the semiconductor substrate.
    Type: Grant
    Filed: May 11, 2015
    Date of Patent: June 9, 2020
    Assignees: TAMURA CORPORATION, NATIONAL UNIVERSITY CORPORATION TOKYO UNIVERSITY OF AGRICULTURE AND TECHNOLOGY
    Inventors: Ken Goto, Akinori Koukitu, Yoshinao Kumagai, Hisashi Murakami
  • Publication number: 20200102667
    Abstract: [Problem] To provide a crystal laminate structure having a ?-Ga2O3 based single crystal film in which a dopant is included throughout the crystal and the concentration of the dopant can be set across a broad range. [Solution] In one embodiment of the present invention, provided is a crystal laminate structure 1 which includes: a Ga2O3 based substrate 10; and a ?-Ga2O3 based single crystal film 12 formed by epitaxial crystal growth on a primary face 11 of the Ga2O3 based substrate 10 and including Cl and a dopant doped in parallel with the crystal growth at a concentration of 1×1013 to 5.0×1020 atoms/cm3.
    Type: Application
    Filed: December 3, 2019
    Publication date: April 2, 2020
    Applicants: TAMURA CORPORATION, NATIONAL UNIVERSITY CORPORATION TOKYO UNIVERSITY OF AGRICULTURE AND TECHNOLOGY
    Inventors: Ken GOTO, Akinori KOUKITU, Yoshinao KUMAGAI, Hisashi MURAKAMI
  • Publication number: 20200071848
    Abstract: This disclosure provides a vapor-liquid reaction device including a vapor-liquid reaction chamber and a projecting member. The vapor-liquid reaction chamber holds a molten metal in a lower portion of an internal space of the vapor-liquid reaction chamber.
    Type: Application
    Filed: May 17, 2018
    Publication date: March 5, 2020
    Applicants: National University Corporation Tokyo University of Agriculture and Technology, Taiyo Nippon Sanso Corporation, Taiyo Nippon Sanso CSE Corporation
    Inventors: Akinori Koukitu, Hisashi Murakami, Akira Yamaguchi, Kazushige Shiina, Hayato Shimamura
  • Patent number: 10538862
    Abstract: A crystal laminate structure includes a Ga2O3-based substrate, and a ?-Ga2O3-based single crystal film formed by epitaxial crystal growth on a principal surface of the Ga2O3-based substrate. The ?-Ga2O3-based single crystal film includes Cl and a dopant doped in parallel with the crystal growth at a concentration of not less than 1×1013 atoms/cm3 and not more than 5.0×1020 atoms/cm3.
    Type: Grant
    Filed: February 17, 2016
    Date of Patent: January 21, 2020
    Assignees: TAMURA CORPORATION, NATIONAL UNIVERSITY CORPORATION TOKYO UNIVERSITY OF AGRICULTURE AND TECHNOLOGY
    Inventors: Ken Goto, Akinori Koukitu, Yoshinao Kumagai, Hisashi Murakami
  • Patent number: 10199512
    Abstract: A high withstand voltage Schottky barrier diode includes a first layer that includes a first Ga2O3-based single crystal including a first Group IV element and Cl at a concentration of not more than 5×1016 cm?3 and that has an effective donor concentration of not less than 1×1013 and not more than 6.0×1017 cm?3, a second layer that includes a second Ga2O3-based single crystal including a second Group IV element and that has a higher effective donor concentration than the first layer and is laminated on the first layer, an anode electrode formed on the first layer, and a cathode electrode formed on the second layer.
    Type: Grant
    Filed: March 9, 2016
    Date of Patent: February 5, 2019
    Assignees: TAMURA CORPORATION, NATIONAL INSTITUTE OF INFORMATION AND COMMUNICATIONS TECHNOLOGY, NATIONAL UNIVERSITY CORPORATION TOKYO UNIVERSITY OF AGRICULTURE AND TECHNOLOGY
    Inventors: Kohei Sasaki, Ken Goto, Masataka Higashiwaki, Akinori Koukitu, Yoshinao Kumagai, Hisashi Murakami
  • Publication number: 20190010605
    Abstract: The present invention provides a novel method for producing a GaN crystal, the method including growing GaN from vapor phase on a semi-polar or non-polar GaN surface using GaCl3 and NH3 as raw materials. Provided herein is an invention of a method for producing a GaN crystal, including the steps of: (i) preparing a GaN seed crystal having a non-polar or semi-polar surface whose normal direction forms an angle of 85° or more and less than 170° with a [0001] direction of the GaN seed crystal; and (ii) growing GaN from vapor phase on a surface including the non-polar or semi-polar surface of the GaN seed crystal using GaCl3 and NH3 as raw materials.
    Type: Application
    Filed: September 13, 2018
    Publication date: January 10, 2019
    Applicants: MITSUBISHI CHEMICAL CORPORATION, NATIONAL UNIVERSITY CORPORATION TOKYO UNIVERSITY OF AGRICULTURE AND TECHNOLOGY
    Inventors: Kenji ISO, Akinori KOUKITU, Hisashi MURAKAMI
  • Patent number: 10125433
    Abstract: A nitride semiconductor crystal has a diameter of four inches or more and is warped to have a curvature radius of 100 m or more, and has an impurity concentration of 1×1017/cm3 or lower. A manufacturing method for a nitride semiconductor crystal includes providing a substrate, feeding a gallium trihalide gas having a partial pressure of 9.0×10?3 atm or higher onto the substrate, and growing a GaN crystal in the ?C-axis direction on the substrate, where a growth temperature for the GaN crystal is 1200° C. or higher, or a manufacturing method for a nitride semiconductor crystal includes providing a substrate, feeding an aluminum trihalide gas having a partial pressure of 9.0×10?3 atm or higher onto the substrate, and growing an AlN crystal in the ?C-axis direction on the substrate, where a growth temperature for the AlN crystal is 1400° C. or higher.
    Type: Grant
    Filed: March 8, 2016
    Date of Patent: November 13, 2018
    Assignees: National University Corporation Tokyo, University of Agriculture and Technology
    Inventors: Akinori Koukitu, Yoshinao Kumagai, Hisashi Murakami
  • Publication number: 20180269351
    Abstract: InGaN-based light-emitting devices fabricated on an InGaN template layer are disclosed.
    Type: Application
    Filed: May 22, 2018
    Publication date: September 20, 2018
    Inventors: Michael R. Krames, Mark P. D'Evelyn, Akinori Koukitu, Yoshinao Kumagai, Hisashi Murakami
  • Publication number: 20180254355
    Abstract: A high withstand voltage Schottky barrier diode includes a first layer that includes a first Ga2O3-based single crystal including a first Group IV element and Cl at a concentration of not more than 5×1016 cm?3 and that has an effective donor concentration of not less than 1×1013 and not more than 6.0×1017 cm?3, a second layer that includes a second Ga2O3-based single crystal including a second Group IV element and that has a higher effective donor concentration than the first layer and is laminated on the first layer, an anode electrode formed on the first layer, and a cathode electrode formed on the second layer.
    Type: Application
    Filed: March 9, 2016
    Publication date: September 6, 2018
    Applicants: TAMURA CORPORATION, National Institute of Information and Communications Technology, National University Corporation Tokyo University of Agriculture and Technology
    Inventors: Kohei SASAKI, Ken GOTO, Masataka HIGASHIWAKI, Akinori KOUKITU, Yoshinao KUMAGAI, Hisashi MURAKAMI
  • Patent number: 10011921
    Abstract: To provide a method for producing a Group III element nitride crystal by growing it on a plane on the ?c-plane side as a crystal growth plane. The present invention is a method for producing a Group III element nitride crystal, including a vapor phase growth step of growing a Group III element nitride crystal 12 on a crystal growth plane of a Group III element nitride seed crystal 11 by vapor deposition. The vapor phase growth step is a step of causing a Group III metal, an oxidant, and a nitrogen-containing gas to react with one another to grow the Group III element nitride crystal 12 or includes: a reduced product gas generation step of causing a Group III element oxide and a reducing gas to react with each other to generate a gas of a reduced product of the Group III element oxide; and a crystal generation step of causing the gas of the reduced product and a nitrogen-containing gas to react with each other to generate the Group III element nitride crystal 12.
    Type: Grant
    Filed: October 28, 2015
    Date of Patent: July 3, 2018
    Assignees: Osaka University, Itochu Plastics Inc., National University Corporation Tokyo University of Agriculture and Technology
    Inventors: Yusuke Mori, Masashi Yoshimura, Mamoru Imade, Masashi Isemura, Akinori Koukitu
  • Patent number: 9978904
    Abstract: InGaN-based light-emitting devices fabricated on an InGaN template layer are disclosed.
    Type: Grant
    Filed: October 15, 2013
    Date of Patent: May 22, 2018
    Assignee: Soraa, Inc.
    Inventors: Michael R. Krames, Mark P. D'Evelyn, Akinori Koukitu, Yoshinao Kumagai, Hisashi Murakami
  • Publication number: 20180073164
    Abstract: A crystal laminate structure includes a Ga2O3-based substrate, and a ?-Ga2O3-based single crystal film formed by epitaxial crystal growth on a principal surface of the Ga2O3-based substrate. The ?-Ga2O3-based single crystal film includes Cl and a dopant doped in parallel with the crystal growth at a concentration of not less than 1×1013 atoms/cm3 and not more than 5.0×1020 atoms/cm3.
    Type: Application
    Filed: February 17, 2016
    Publication date: March 15, 2018
    Applicants: TAMURA CORPORATION, NATIONAL UNIVERSITY CORPORATION TOKYO UNIVERSITY O F AGRICULTURE AND TECHNOLOGY
    Inventors: Ken GOTO, Akinori KOUKITU, Yoshinao KUMAGAI, Hisashi MURAKAMI
  • Patent number: 9840790
    Abstract: The invention provides highly transparent single crystalline AlN layers as device substrates for light emitting diodes in order to improve the output and operational degradation of light emitting devices. The highly transparent single crystalline AlN layers have a refractive index in the a-axis direction in the range of 2.250 to 2.400 and an absorption coefficient less than or equal to 15 cm-1 at a wavelength of 265 nm. The invention also provides a method for growing highly transparent single crystalline AlN layers, the method including the steps of maintaining the amount of Al contained in wall deposits formed in a flow channel of a reactor at a level lower than or equal to 30% of the total amount of aluminum fed into the reactor, and maintaining the wall temperature in the flow channel at less than or equal to 1200° C.
    Type: Grant
    Filed: August 23, 2012
    Date of Patent: December 12, 2017
    Assignees: Hexatech, Inc., National University Corporation Tokyo University of Agriculture and Technology, Tokuyama Corporation
    Inventors: Akinori Koukitu, Yoshinao Kumagai, Toru Nagashima, Toru Kinoshita, Yuki Kubota, Rafael F. Dalmau, Jinqiao Xie, Baxter F. Moody, Raoul Schlesser, Zlatko Sitar
  • Publication number: 20170321348
    Abstract: To provide a method for producing a Group III element nitride crystal by growing it on a plane on the ?c-plane side as a crystal growth plane. The present invention is a method for producing a Group III element nitride crystal, including a vapor phase growth step of growing a Group III element nitride crystal 12 on a crystal growth plane of a Group III element nitride seed crystal 11 by vapor deposition. The vapor phase growth step is a step of causing a Group III metal, an oxidant, and a nitrogen-containing gas to react with one another to grow the Group III element nitride crystal 12 or includes: a reduced product gas generation step of causing a Group III element oxide and a reducing gas to react with each other to generate a gas of a reduced product of the Group III element oxide; and a crystal generation step of causing the gas of the reduced product and a nitrogen-containing gas to react with each other to generate the Group III element nitride crystal 12.
    Type: Application
    Filed: October 28, 2015
    Publication date: November 9, 2017
    Inventors: Yusuke MORI, Masashi YOSHIMURA, Mamoru IMADE, Masashi ISEMURA, Akinori KOUKITU
  • Patent number: 9691942
    Abstract: The present invention relates to a single-crystalline aluminum nitride wherein a carbon concentration is 1×1014 atoms/cm3 or more and less than 3×1017 atoms/cm3, a chlorine concentration is 1×1014 to 1×1017 atoms/cm3, and an absorption coefficient at 265 nm wavelength is 40 cm?1 or less.
    Type: Grant
    Filed: December 22, 2011
    Date of Patent: June 27, 2017
    Assignees: National University Corporation Tokyo University of Agriculture and Technology, Tokuyama Corporation
    Inventors: Akinori Koukitu, Yoshinao Kumagai, Toru Nagashima, Yuki Hiraren