Patents by Inventor Hirotaka Ikeda

Hirotaka Ikeda 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: 20230392280
    Abstract: An object of the present invention is to provide a GaN crystal long in light emission lifetime by time-resolved photoluminescence measurement and provide high-quality GaN crystal and GaN substrate that have few specified crystal defects affecting the light emission lifetime. A gallium nitride crystal having a light emission lifetime by time-resolved photoluminescence measurement, of 5 ps or more and 200 ps or less, and satisfying at least one of the following requirement (i) and requirement (ii): (i) an FWHM in a 004 diffraction X-ray rocking curve is 50 arcsec or less at least one position of the crystal; and (ii) a dislocation density is 5×106 cm?2 or less.
    Type: Application
    Filed: August 24, 2023
    Publication date: December 7, 2023
    Applicants: MITSUBISHI CHEMICAL CORPORATION, THE JAPAN STEEL WORKS, LTD., TOHOKU UNIVERSITY
    Inventors: Yutaka MIKAWA, Hirotaka IKEDA, Quanxi BAO, Kouhei KURIMOTO, Kohei SHIMA, Kazunobu KOJIMA, Toru ISHIGURO, Shigefusa CHICHIBU
  • Publication number: 20230253461
    Abstract: An object is to provide a nonpolar or semipolar GaN substrate having improved size and crystal quality. A self-standing GaN substrate has an angle between the normal of the principal surface and an m-axis of 0 degrees or more and 20 degrees or less, wherein: the size of the projected image in a c-axis direction when the principal surface is vertically projected on an M-plane is 10 mm or more; and when an a-axis length is measured on an intersection line between the principal surface and an A-plane, a low distortion section with a section length of 6 mm or more and with an a-axis length variation within the section of 10.0×10?5 ? or less is observed.
    Type: Application
    Filed: April 18, 2023
    Publication date: August 10, 2023
    Applicant: Mitsubishi Chemical Corporation
    Inventors: Satoru NAGAO, Yusuke TSUKADA, azunori KAMADA, Shuichi KUBO, Hirotaka IKEDA, Kenji FUJITO, Hideo FUJISAWA, Yutaka MIKAWA, Tae MOCHIZUKI
  • Patent number: 11670687
    Abstract: A gallium nitride substrate comprising a first main surface and a second main surface opposite thereto, wherein the first main surface is a non-polar or semi-polar plane, a dislocation density measured by a room-temperature cathode luminescence method in the first main surface is 1×104 cm?2 or less, and an averaged dislocation density measured by a room-temperature cathode luminescence method in an optional square region sizing 250 ?m×250 ?m in the first main plan is 1×106 cm?2 or less.
    Type: Grant
    Filed: June 19, 2020
    Date of Patent: June 6, 2023
    Assignee: MITSUBISHI CHEMICAL CORPORATION
    Inventors: Yusuke Tsukada, Shuichi Kubo, Kazunori Kamada, Hideo Fujisawa, Tatsuhiro Ohata, Hirotaka Ikeda, Hajime Matsumoto, Yutaka Mikawa
  • Patent number: 11664428
    Abstract: An object is to provide a nonpolar or semipolar GaN substrate having improved size and crystal quality. A self-standing GaN substrate has an angle between the normal of the principal surface and an m-axis of 0 degrees or more and 20 degrees or less, wherein: the size of the projected image in a c-axis direction when the principal surface is vertically projected on an M-plane is 10 mm or more; and when an a-axis length is measured on an intersection line between the principal surface and an A-plane, a low distortion section with a section length of 6 mm or more and with an a-axis length variation within the section of 10.0×10?5 ? or less is observed.
    Type: Grant
    Filed: April 23, 2021
    Date of Patent: May 30, 2023
    Assignee: Mitsubishi Chemical Corporation
    Inventors: Satoru Nagao, Yusuke Tsukada, Kazunori Kamada, Shuichi Kubo, Hirotaka Ikeda, Kenji Fujito, Hideo Fujisawa, Yutaka Mikawa, Tae Mochizuki
  • Publication number: 20210273058
    Abstract: An object is to provide a nonpolar or semipolar GaN substrate having improved size and crystal quality. A self-standing GaN substrate has an angle between the normal of the principal surface and an m-axis of 0 degrees or more and 20 degrees or less, wherein: the size of the projected image in a c-axis direction when the principal surface is vertically projected on an M-plane is 10 mm or more; and when an a-axis length is measured on an intersection line between the principal surface and an A-plane, a low distortion section with a section length of 6 mm or more and with an a-axis length variation within the section of 10.0×10?5 ? or less is observed.
    Type: Application
    Filed: April 23, 2021
    Publication date: September 2, 2021
    Applicant: Mitsubishi Chemical Corporation
    Inventors: Satoru NAGAO, Yusuke TSUKADA, Kazunori KAMADA, Shuichi KUBO, Hirotaka IKEDA, Kenji FUJITO, Hideo FUJISAWA, Yutaka MIKAWA, Tae MOCHIZUKI
  • Patent number: 11038024
    Abstract: An object is to provide a nonpolar or semipolar GaN substrate having improved size and crystal quality. A self-standing GaN substrate has an angle between the normal of the principal surface and an m-axis of 0 degrees or more and 20 degrees or less, wherein: the size of the projected image in a c-axis direction when the principal surface is vertically projected on an M-plane is 10 mm or more; and when an a-axis length is measured on an intersection line between the principal surface and an A-plane, a low distortion section with a section length of 6 mm or more and with an a-axis length variation within the section of 10.0×10?5 ? or less is observed.
    Type: Grant
    Filed: June 18, 2019
    Date of Patent: June 15, 2021
    Assignee: Mitsubishi Chemical Corporation
    Inventors: Satoru Nagao, Yusuke Tsukada, Kazunori Kamada, Shuichi Kubo, Hirotaka Ikeda, Kenji Fujito, Hideo Fujisawa, Yutaka Mikawa, Tae Mochizuki
  • Patent number: 11031475
    Abstract: An object is to provide a nonpolar or semipolar GaN substrate having improved size and crystal quality. A self-standing GaN substrate has an angle between the normal of the principal surface and an m-axis of 0 degrees or more and 20 degrees or less, wherein: the size of the projected image in a c-axis direction when the principal surface is vertically projected on an M-plane is 10 mm or more; and when an a-axis length is measured on an intersection line between the principal surface and an A-plane, a low distortion section with a section length of 6 mm or more and with an a-axis length variation within the section of 10.0×10 ?5 ? or less is observed.
    Type: Grant
    Filed: September 18, 2019
    Date of Patent: June 8, 2021
    Assignee: Mitsubishi Chemical Corporation
    Inventors: Satoru Nagao, Yusuke Tsukada, Kazunori Kamada, Shuichi Kubo, Hirotaka Ikeda, Kenji Fujito, Hideo Fujisawa, Yutaka Mikawa, Tae Mochizuki
  • Patent number: 10995421
    Abstract: An object of the present invention is to provide a crystal of a nitride of a Group-13 metal on the Periodic Table which has good crystallinity and has no crystal strain, and to provide a production method for the crystal. The crystal of a nitride of a Group-13 metal on the Periodic Table of the present invention, comprises oxygen atom and hydrogen atom in the crystal and has a ratio of a hydrogen concentration to an oxygen concentration therein of from 0.5 to 4.5.
    Type: Grant
    Filed: March 8, 2019
    Date of Patent: May 4, 2021
    Assignee: MITSUBISHI CHEMICAL CORPORATION
    Inventors: Yutaka Mikawa, Hideo Namita, Hirotaka Ikeda, Kazunori Kamada, Hideo Fujisawa, Atsuhiko Kojima
  • Publication number: 20200321438
    Abstract: A gallium nitride substrate comprising a first main surface and a second main surface opposite thereto, wherein the first main surface is a non-polar or semi-polar plane, a dislocation density measured by a room-temperature cathode luminescence method in the first main surface is 1×104 cm?2 or less, and an averaged dislocation density measured by a room-temperature cathode luminescence method in an optional square region sizing 250 ?m×250 ?m in the first main plan is 1×106 cm?2 or less.
    Type: Application
    Filed: June 19, 2020
    Publication date: October 8, 2020
    Applicant: MITSUBISHI CHEMICAL CORPORATION
    Inventors: Yusuke Tsukada, Shuichi Kubo, Kazunori Kamada, Hideo Fujisawa, Tatsuhiro Ohata, Hirotaka Ikeda, Hajime Matsumoto, Yutaka Mikawa
  • Patent number: 10734485
    Abstract: The main purpose of the present invention is to provide: a nonpolar or semipolar GaN substrate, in which a nitride semiconductor crystal having a low stacking fault density can be epitaxially grown on the main surface of the substrate, and a technique required for the production of the substrate. This invention provides: a method for manufacturing an M-plane GaN substrate comprising; forming a mask pattern having a line-shaped opening parallel to an a-axis of a C-plane GaN substrate on an N-polar plane of the C-plane GaN substrate, growing a plane-shape GaN crystal of which thickness direction is an m-axis direction from the opening of the mask pattern by an ammonotharmal method, and cutting out the M-plane GaN substrate from the plane-shape GaN crystal.
    Type: Grant
    Filed: March 29, 2017
    Date of Patent: August 4, 2020
    Assignee: MITSUBISHI CHEMICAL CORPORATION
    Inventors: Yusuke Tsukada, Shuichi Kubo, Kazunori Kamada, Hideo Fujisawa, Tatsuhiro Ohata, Hirotaka Ikeda, Hajime Matsumoto, Yutaka Mikawa
  • Patent number: 10570530
    Abstract: A periodic table Group 13 metal nitride crystals grown with a non-polar or semi-polar principal surface have numerous stacking faults. The purpose of the present invention is to provide a period table Group 13 metal nitride crystal wherein the occurrence of stacking faults of this kind are suppressed. The present invention achieves the foregoing by a periodic table Group 13 metal nitride crystal being characterized in that, in a Qx direction intensity profile that includes a maximum intensity and is derived from an isointensity contour plot obtained by x-ray reciprocal lattice mapping of (100) plane of the periodic table Group 13 metal nitride crystal, a Qx width at 1/300th of peak intensity is 6×10?4 rlu or less.
    Type: Grant
    Filed: May 11, 2018
    Date of Patent: February 25, 2020
    Assignee: Mitsubishi Chemical Corporation
    Inventors: Yuuki Enatsu, Satoru Nagao, Shuichi Kubo, Hirotaka Ikeda, Kenji Fujito
  • Publication number: 20200013860
    Abstract: An object is to provide a nonpolar or semipolar GaN substrate having improved size and crystal quality. A self-standing GaN substrate has an angle between the normal of the principal surface and an m-axis of 0 degrees or more and 20 degrees or less, wherein: the size of the projected image in a c-axis direction when the principal surface is vertically projected on an M-plane is 10 mm or more; and when an a-axis length is measured on an intersection line between the principal surface and an A-plane, a low distortion section with a section length of 6 mm or more and with an a-axis length variation within the section of 10.0×10?5 ? or less is observed.
    Type: Application
    Filed: September 18, 2019
    Publication date: January 9, 2020
    Applicant: Mitsubishi Chemical Corporation
    Inventors: Satoru NAGAO, Yusuke Tsukada, Kazunori Kamada, Shuichi Kubo, Hirotaka Ikeda, Kenji Fujito, Hideo Fujisawa, Yutaka Mikawa, Tae Mochizuki
  • Patent number: 10475887
    Abstract: An object is to provide a nonpolar or semipolar GaN substrate having improved size and crystal quality. A self-standing GaN substrate has an angle between the normal of the principal surface and an m-axis of 0 degrees or more and 20 degrees or less, wherein: the size of the projected image in a c-axis direction when the principal surface is vertically projected on an M-plane is 10 mm or more; and when an a-axis length is measured on an intersection line between the principal surface and an A-plane, a low distortion section with a section length of 6 mm or more and with an a-axis length variation within the section of 10.0×10?5 ? or less is observed.
    Type: Grant
    Filed: February 5, 2016
    Date of Patent: November 12, 2019
    Assignee: Mitsubishi Chemical Corporation
    Inventors: Satoru Nagao, Yusuke Tsukada, Kazunori Kamada, Shuichi Kubo, Hirotaka Ikeda, Kenji Fujito, Hideo Fujisawa, Yutaka Mikawa, Tae Mochizuki
  • Publication number: 20190312111
    Abstract: An object is to provide a nonpolar or semipolar GaN substrate having improved size and crystal quality. A self-standing GaN substrate has an angle between the normal of the principal surface and an m-axis of 0 degrees or more and 20 degrees or less, wherein: the size of the projected image in a c-axis direction when the principal surface is vertically projected on an M-plane is 10 mm or more; and when an a-axis length is measured on an intersection line between the principal surface and an A-plane, a low distortion section with a section length of 6 mm or more and with an a-axis length variation within the section of 10.0×10?5 ? or less is observed.
    Type: Application
    Filed: June 18, 2019
    Publication date: October 10, 2019
    Applicant: Mitsubishi Chemical Corporation
    Inventors: Satoru NAGAO, Yusuke TSUKADA, Kazunori KAMADA, Shuichi KUBO, Hirotaka IKEDA, Kenji FUJITO, Hideo FUJISAWA, Yutaka MIKAWA, Tae MOCHIZUKI
  • Publication number: 20190203379
    Abstract: An object of the present invention is to provide a crystal of a nitride of a Group-13 metal on the Periodic Table which has good crystallinity and has no crystal strain, and to provide a production method for the crystal. The crystal of a nitride of a Group-13 metal on the Periodic Table of the present invention, comprises oxygen atom and hydrogen atom in the crystal and has a ratio of a hydrogen concentration to an oxygen concentration therein of from 0.5 to 4.5.
    Type: Application
    Filed: March 8, 2019
    Publication date: July 4, 2019
    Applicant: MITSUBISHI CHEMICAL CORPORATION
    Inventors: Yutaka Mikawa, Hideo Namita, Hirotaka Ikeda, Kazunori Kamada, Hideo Fujisawa, Atsuhiko Kojima
  • Patent number: 10309038
    Abstract: An object of the present invention is to provide a crystal of a nitride of a Group-13 metal on the Periodic Table which has good crystallinity and has no crystal strain, and to provide a production method for the crystal. The crystal of a nitride of a Group-13 metal on the Periodic Table of the present invention, comprises oxygen atom and hydrogen atom in the crystal and has a ratio of a hydrogen concentration to an oxygen concentration therein of from 0.5 to 4.5.
    Type: Grant
    Filed: December 14, 2017
    Date of Patent: June 4, 2019
    Assignee: MITSUBISHI CHEMICAL CORPORATION
    Inventors: Yutaka Mikawa, Hideo Namita, Hirotaka Ikeda, Kazunori Kamada, Hideo Fujisawa, Atsuhiko Kojima
  • Publication number: 20180258552
    Abstract: A periodic table Group 13 metal nitride crystals grown with a non-polar or semi-polar principal surface have numerous stacking faults. The purpose of the present invention is to provide a period table Group 13 metal nitride crystal wherein the occurrence of stacking faults of this kind are suppressed. The present invention achieves the foregoing by a periodic table Group 13 metal nitride crystal being characterized in that, in a Qx direction intensity profile that includes a maximum intensity and is derived from an isointensity contour plot obtained by x-ray reciprocal lattice mapping of (100) plane of the periodic table Group 13 metal nitride crystal, a Qx width at 1/300th of peak intensity is 6×10?4 rlu or less.
    Type: Application
    Filed: May 11, 2018
    Publication date: September 13, 2018
    Applicant: Mitsubishi Chemical Corporation
    Inventors: Yuuki ENATSU, Satoru NAGAO, Shuichi KUBO, Hirotaka IKEDA, Kenji FUJITO
  • Patent number: 10023976
    Abstract: A periodic table Group 13 metal nitride crystals grown with a non-polar or semi-polar principal surface have numerous stacking faults. The purpose of the present invention is to provide a period table Group 13 metal nitride crystal wherein the occurrence of stacking faults of this kind are suppressed. The present invention achieves the foregoing by a periodic table Group 13 metal nitride crystal being characterized in that, in a Qx direction intensity profile that includes a maximum intensity and is derived from an isointensity contour plot obtained by x-ray reciprocal lattice mapping of (100) plane of the periodic table Group 13 metal nitride crystal, a Qx width at 1/300th of peak intensity is 6×10?4 rlu or less.
    Type: Grant
    Filed: November 1, 2017
    Date of Patent: July 17, 2018
    Assignee: MITSUBISHI CHEMICAL CORPORATION
    Inventors: Yuuki Enatsu, Satoru Nagao, Shuichi Kubo, Hirotaka Ikeda, Kenji Fujito
  • Publication number: 20180105953
    Abstract: An object of the present invention is to provide a crystal of a nitride of a Group-13 metal on the Periodic Table which has good crystallinity and has no crystal strain, and to provide a production method for the crystal. The crystal of a nitride of a Group-13 metal on the Periodic Table of the present invention, comprises oxygen atom and hydrogen atom in the crystal and has a ratio of a hydrogen concentration to an oxygen concentration therein of from 0.5 to 4.5.
    Type: Application
    Filed: December 14, 2017
    Publication date: April 19, 2018
    Applicant: MITSUBISHI CHEMICAL CORPORATION
    Inventors: Yutaka MIKAWA, Hideo Namita, Hirotaka Ikeda, Kazunori Kamada, Hideo Fujisawa, Atsuhiko Kojima
  • Publication number: 20180057960
    Abstract: A periodic table Group 13 metal nitride crystals grown with a non-polar or semi-polar principal surface have numerous stacking faults. The purpose of the present invention is to provide a period table Group 13 metal nitride crystal wherein the occurrence of stacking faults of this kind are suppressed. The present invention achieves the foregoing by a periodic table Group 13 metal nitride crystal being characterized in that, in a Qx direction intensity profile that includes a maximum intensity and is derived from an isointensity contour plot obtained by x-ray reciprocal lattice mapping of (100) plane of the periodic table Group 13 metal nitride crystal, a Qx width at 1/300th of peak intensity is 6×10?4 rlu or less.
    Type: Application
    Filed: November 1, 2017
    Publication date: March 1, 2018
    Applicant: Mitsubishi Chemical Corporation
    Inventors: Yuuki ENATSU, Satoru NAGAO, Shuichi KUBO, Hirotaka IKEDA, Kenji FUJITO