Patents by Inventor Kenji Iso

Kenji Iso 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: 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
  • Publication number: 20210164127
    Abstract: Provided is an n-type GaN crystal, in which a donor impurity contained at the highest concentration is Ge, and which has a room-temperature resistivity of lower than 0.03 ?·cm and a (004) XRD rocking curve FWHM of less than 20 arcsec. The n-type GaN crystal has two main surfaces, each having an area of 2 cm2 or larger. One of the two main surfaces can have a Ga polarity and can be inclined at an angle of 0° to 10° with respect to a (0001) crystal plane. Further, the n-type GaN crystal can have a diameter of 20 mm or larger.
    Type: Application
    Filed: February 16, 2021
    Publication date: June 3, 2021
    Applicant: MITSUBISHI CHEMICAL CORPORATION
    Inventors: Kenji ISO, Tatsuya TAKAHASHI, Tae MOCHIZUKI, Yuuki ENATSU
  • 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: 10224201
    Abstract: Provides is a C-plane GaN substrate which, although formed from a GaN crystal grown so that surface pits are generated, is free from any inversion domain, and moreover, has a low spiral dislocation density in a gallium polar surface. Provides is a C-plane GaN substrate wherein: the substrate comprises a plurality of facet growth areas each having a closed ring outline-shape on a gallium polar surface; the spiral dislocation density is less than 1×106 cm?2 anywhere on the gallium polar surface; and the substrate is free from any inversion domain. The C-plane GaN substrate may comprise a high dislocation density part having a dislocation density of more than 1×107 cm?2 and a low dislocation density part having a dislocation density of less than 1×106 cm?2 on the gallium polar surface.
    Type: Grant
    Filed: August 11, 2017
    Date of Patent: March 5, 2019
    Assignee: MITSUBISHI CHEMICAL CORPORATION
    Inventors: Kenji Iso, Yuuki Enatsu, Hiromitsu Kimura
  • 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: 10177217
    Abstract: A C-plane GaN substrate only mildly restricts the shape and dimension of a nitride semiconductor device formed on the substrate. The variation of an off-angle on the main surface of the substrate is suppressed. In the C-plane GaN substrate: the substrate comprises a plurality of facet growth areas each having a closed ring outline-shape on the main surface; the number density of the facet growth area accompanied by a core among the plurality of facet growth areas is less than 5 cm?2 on the main surface; and, when any circular area of 4 cm diameter is selected from an area which is on the main surface and is distant by 5 mm or more from the outer peripheral edge of the substrate, the variation widths of an a-axis direction component and an m-axis direction component of an off-angle within the circular area is each 0.25 degrees or less.
    Type: Grant
    Filed: August 21, 2017
    Date of Patent: January 8, 2019
    Assignee: MITSUBISHI CHEMICAL CORPORATION
    Inventors: Kenji Iso, Hiromitsu Kimura, Yuya Saito, Yuuki Enatsu
  • Publication number: 20170352721
    Abstract: A C-plane GaN substrate only mildly restricts the shape and dimension of a nitride semiconductor device formed on the substrate. The variation of an off-angle on the main surface of the substrate is suppressed. In the C-plane GaN substrate: the substrate comprises a plurality of facet growth areas each having a closed ring outline-shape on the main surface; the number density of the facet growth area accompanied by a core among the plurality of facet growth areas is less than 5 cm?2 on the main surface; and, when any circular area of 4 cm diameter is selected from an area which is on the main surface and is distant by 5 mm or more from the outer peripheral edge of the substrate, the variation widths of an a-axis direction component and an m-axis direction component of an off-angle within the circular area is each 0.25 degrees or less.
    Type: Application
    Filed: August 21, 2017
    Publication date: December 7, 2017
    Applicant: MITSUBISHI CHEMICAL CORPORATION
    Inventors: Kenji ISO, Hiromitsu KIMURA, Yuya SAITO, Yuuki ENATSU
  • Patent number: 9828695
    Abstract: A nonpolar III-nitride film grown on a miscut angle of a substrate, in order to suppress the surface undulations, is provided. The surface morphology of the film is improved with a miscut angle towards an a-axis direction comprising a 0.15° or greater miscut angle towards the a-axis direction and a less than 30° miscut angle towards the a-axis direction.
    Type: Grant
    Filed: April 20, 2016
    Date of Patent: November 28, 2017
    Assignee: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Asako Hirai, Zhongyuan Jia, Makoto Saito, Hisashi Yamada, Kenji Iso, Steven P. DenBaars, Shuji Nakamura, James S. Speck
  • Publication number: 20170338112
    Abstract: Provides is a C-plane GaN substrate which, although formed from a GaN crystal grown so that surface pits are generated, is free from any inversion domain, and moreover, has a low spiral dislocation density in a gallium polar surface. Provides is a C-plane GaN substrate wherein: the substrate comprises a plurality of facet growth areas each having a closed ring outline-shape on a gallium polar surface; the spiral dislocation density is less than 1×106 cm?2 anywhere on the gallium polar surface; and the substrate is free from any inversion domain. The C-plane GaN substrate may comprise a high dislocation density part having a dislocation density of more than 1×107 cm?2 and a low dislocation density part having a dislocation density of less than 1×106 cm?2 on the gallium polar surface.
    Type: Application
    Filed: August 11, 2017
    Publication date: November 23, 2017
    Applicant: MITSUBISHI CHEMICAL CORPORATION
    Inventors: Kenji ISO, Yuuki ENATSU, Hiromitsu KIMURA
  • Publication number: 20170327969
    Abstract: A nonpolar III-nitride film grown on a miscut angle of a substrate. The miscut angle towards the <000-1> direction is 0.75° or greater miscut and less than 27° miscut towards the <000-1> direction. Surface undulations are suppressed and may comprise faceted pyramids. A device fabricated using the film is also disclosed. A nonpolar III-nitride film having a smooth surface morphology fabricated using a method comprising selecting a miscut angle of a substrate upon which the nonpolar III-nitride films are grown in order to suppress surface undulations of the nonpolar III-nitride films. A nonpolar III-nitride-based device grown on a film having a smooth surface morphology grown on a miscut angle of a substrate which the nonpolar III-nitride films are grown. The miscut angle may also be selected to achieve long wavelength light emission from the nonpolar film.
    Type: Application
    Filed: May 26, 2017
    Publication date: November 16, 2017
    Applicant: The Regents of the University of California
    Inventors: Kenji Iso, Hisashi Yamada, Makoto Saito, Asako Hirai, Steven P. DenBaars, James S. Speck, Shuji Nakamura
  • Publication number: 20160230312
    Abstract: A nonpolar III-nitride film grown on a miscut angle of a substrate, in order to suppress the surface undulations, is provided. The surface morphology of the film is improved with a miscut angle towards an ?-axis direction comprising a 0.15° or greater miscut angle towards the ?-axis direction and a less than 30° miscut angle towards the ?-axis direction.
    Type: Application
    Filed: April 20, 2016
    Publication date: August 11, 2016
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Asako Hirai, Zhongyuan Jia, Makoto Saito, Hisashi Yamada, Kenji Iso, Steven P. DenBaars, Shuji Nakamura, James S. Speck
  • Patent number: 9340899
    Abstract: A nonpolar III-nitride film grown on a miscut angle of a substrate, in order to suppress the surface undulations, is provided. The surface morphology of the film is improved with a miscut angle towards an a-axis direction comprising a 0.15° or greater miscut angle towards the a-axis direction and a less than 30° miscut angle towards the a-axis direction.
    Type: Grant
    Filed: June 16, 2014
    Date of Patent: May 17, 2016
    Assignee: The Regents of the University of California
    Inventors: Asako Hirai, Zhongyuan Jia, Makoto Saito, Hisashi Yamada, Kenji Iso, Steven P. DenBaars, Shuji Nakamura, James S. Speck
  • Publication number: 20140291694
    Abstract: A nonpolar III-nitride film grown on a miscut angle of a substrate, in order to suppress the surface undulations, is provided. The surface morphology of the film is improved with a miscut angle towards an a-axis direction comprising a 0.15° or greater miscut angle towards the a-axis direction and a less than 30° miscut angle towards the a-axis direction.
    Type: Application
    Filed: June 16, 2014
    Publication date: October 2, 2014
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Asako Hirai, Zhongyuan Jia, Makoto Saito, Hisashi Yamada, Kenji Iso, Steven P. DenBaars, Shuji Nakamura, James S. Speck
  • Patent number: 8791000
    Abstract: A nonpolar III-nitride film grown on a miscut angle of a substrate, in order to suppress the surface undulations, is provided. The surface morphology of the film is improved with a miscut angle towards an a-axis direction comprising a 0.15° or greater miscut angle towards the a-axis direction and a less than 30° miscut angle towards the a-axis direction.
    Type: Grant
    Filed: January 27, 2014
    Date of Patent: July 29, 2014
    Assignee: The Regents of the University of California
    Inventors: Asako Hirai, Zhongyuan Jia, Makoto Saito, Hisashi Yamada, Kenji Iso, Steven P. DenBaars, Shuji Nakamura, James S. Speck
  • Publication number: 20140138679
    Abstract: A nonpolar III-nitride film grown on a miscut angle of a substrate, in order to suppress the surface undulations, is provided. The surface morphology of the film is improved with a miscut angle towards an a-axis direction comprising a 0.15° or greater miscut angle towards the a-axis direction and a less than 30° miscut angle towards the a-axis direction.
    Type: Application
    Filed: January 27, 2014
    Publication date: May 22, 2014
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Asako Hirai, Zhongyuan Jia, Makoto Saito, Hisashi Yamada, Kenji Iso, Steven P. DenBaars, Shuji Nakamura, James S. Speck
  • Patent number: 8691671
    Abstract: A nonpolar III-nitride film grown on a miscut angle of a substrate, in order to suppress the surface undulations, is provided. The surface morphology of the film is improved with a miscut angle towards an ?-axis direction comprising a 0.15° or greater miscut angle towards the ?-axis direction and a less than 30° miscut angle towards the ?-axis direction.
    Type: Grant
    Filed: March 22, 2012
    Date of Patent: April 8, 2014
    Assignee: The Regents of the University of California
    Inventors: Asako Hirai, Zhongyuan Jia, Makoto Saito, Hisashi Yamada, Kenji Iso, Steven P. Denbaars, Shuji Nakamura, James S. Speck
  • Patent number: 8679254
    Abstract: [Problem] Provided is a vapor phase epitaxy apparatus of a group III nitride semiconductor including: a susceptor for holding a substrate; the opposite face of the susceptor; a heater for heating the substrate; a reactor formed of a gap between the susceptor and the opposite face of the susceptor; a raw material gas-introducing portion for supplying a raw material gases from the central portion of the reactor toward the peripheral portion of the reactor; and a reacted gas-discharging portion. Even when crystal growth is conducted on the surfaces of a large number of large-aperture substrates, the vapor phase epitaxy apparatus can eject each raw material gas at an equal flow rate for any angle, and can suppress the decomposition and crystallization of the raw material gases on the opposite face of the susceptor.
    Type: Grant
    Filed: January 26, 2011
    Date of Patent: March 25, 2014
    Assignee: Japan Pionics Co., Ltd.
    Inventors: Kenji Iso, Yoshiyasu Ishihama, Ryohei Takaki, Yuzuru Takahashi
  • Patent number: 8642993
    Abstract: A III-nitride film, grown on an m-plane substrate, includes multiple quantum wells (MQWs) with a barrier thickness of 27.5 nm or greater and a well thickness of 8 nm or greater. An emission wavelength can be controlled by selecting the barrier thickness of the MQWs. Device fabricated using the III-nitride film include nonpolar III-nitride light emitting diodes (LEDs) with a long wavelength emission.
    Type: Grant
    Filed: November 15, 2010
    Date of Patent: February 4, 2014
    Assignee: The Regents of the University of California
    Inventors: Hisashi Yamada, Kenji Iso, Shuji Nakamura
  • Patent number: 8368109
    Abstract: An (Al,Ga,In)N-based light emitting diode (LED), comprising a p-type surface of the LED bonded with a transparent submount material to increase light extraction at the p-type surface, wherein the LED is a substrateless membrane.
    Type: Grant
    Filed: November 15, 2011
    Date of Patent: February 5, 2013
    Assignee: The Regents of the University of California
    Inventors: Kenji Iso, Hirokuni Asamizu, Makoto Saito, Hitoshi Sato, Steven P. DenBaars, Shuji Nakamura
  • Patent number: 8278128
    Abstract: An off-axis cut of a nonpolar III-nitride wafer towards a polar (?c) orientation results in higher polarization ratios for light emission than wafers without such off-axis cuts. A 5° angle for an off-axis cut has been confirmed to provide the highest polarization ratio (0.9) than any other examined angles for off-axis cuts between 0° and 27°.
    Type: Grant
    Filed: February 2, 2009
    Date of Patent: October 2, 2012
    Assignee: The Regents of the University of California
    Inventors: Hisashi Masui, Hisashi Yamada, Kenji Iso, Asako Hirai, Makoto Saito, James S. Speck, Shuji Nakamura, Steven P. DenBaars