Patents by Inventor Takanao Shimodaira

Takanao Shimodaira 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: 20200232120
    Abstract: A layer of a crystal of a group 13 nitride selected from gallium nitride, aluminum nitride, indium nitride and the mixed crystals thereof has an upper surface and a bottom surface. The upper surface of a crystal layer of the group 13 nitride includes a linear high-luminance light-emitting part and a low-luminance light-emitting region adjacent to the high-luminance light-emitting part, observed by cathode luminescence. The high-luminance light-emitting part includes a portion extending along an m-plane of the crystal of the group 13 nitride. A normal line to the upper surface has an off-angle of 2.0° or less with respect to <0001> direction of the crystal of the nitride of the group 13 element.
    Type: Application
    Filed: February 21, 2020
    Publication date: July 23, 2020
    Inventors: Takayuki HIRAO, Hirokazu NAKANISHI, Mikiya ICHIMURA, Takanao SHIMODAIRA, Masahiro SAKAI, Takashi YOSHINO
  • Publication number: 20200203573
    Abstract: It is provided a layer of a crystal of a nitride of a group 13 element selected from gallium nitride, aluminum nitride, indium nitride and the mixed crystals thereof, and the layer includes an upper surface and a bottom surface. The upper surface includes a linear high-luminance light-emitting part and a low-luminance light-emitting region adjacent to the high-luminance light-emitting part, and the high-luminance light-emitting part has a portion extending along an m-plane of the crystal of the nitride of the group 13 element, in the case that the upper surface is observed by cathode luminescence. The upper surface has an arithmetic average roughness Ra of 0.05 nm or more and 1.0 nm or less.
    Type: Application
    Filed: February 21, 2020
    Publication date: June 25, 2020
    Inventors: Takayuki HIRAO, Hirokazu NAKANISHI, Mikiya ICHIMURA, Takanao SHIMODAIRA, Masahiro SAKAI, Takashi YOSHINO
  • Publication number: 20200194626
    Abstract: A layer of a crystal of a group 13 nitride selected from gallium nitride, aluminum nitride, indium nitride and the mixed crystals thereof has an upper surface and a bottom surface. The upper surface of a crystal layer of the group 13 nitride includes a linear high-luminance light-emitting part and a low-luminance light-emitting region adjacent to the high-luminance light-emitting part, observed by cathode luminescence. The high-luminance light-emitting part includes a portion extending along an m-plane of the crystal of the group 13 nitride.
    Type: Application
    Filed: February 21, 2020
    Publication date: June 18, 2020
    Inventors: Takayuki HIRAO, Hirokazu NAKANISHI, Mikiya ICHIMURA, Takanao SHIMODAIRA, Masahiro SAKAI, Takashi YOSHINO
  • Publication number: 20200194621
    Abstract: A layer of a crystal of a group 13 nitride selected from gallium nitride, aluminum nitride, indium nitride and the mixed crystals thereof has an upper surface and a bottom surface. The upper surface of a crystal layer of the group 13 nitride includes a linear high-luminance light-emitting part and a low-luminance light-emitting region adjacent to the high-luminance light-emitting part, observed by cathode luminescence. The high-luminance light-emitting part includes a portion extending along an m-plane of the crystal of the group 13 nitride. The crystal of the nitride of the group 13 element contains oxygen atoms in a content of 1×1018 atom/cm3 or less, silicon atoms, manganese atoms, carbon atoms, magnesium atoms and calcium atoms in contents of 1×1017 atom/cm3 or less, chromium atoms in a content of 1×1016 atom/cm3 or less and chlorine atoms in a content of 1×1015 atom/cm3 or less.
    Type: Application
    Filed: February 21, 2020
    Publication date: June 18, 2020
    Inventors: Takayuki HIRAO, Hirokazu NAKANISHI, Mikiya ICHIMURA, Takanao SHIMODAIRA, Masahiro SAKAI, Takashi YOSHINO
  • Publication number: 20200190695
    Abstract: It is provided a layer of a crystal of a group 13 nitride having an upper surface and lower surface and composed of a crystal of the group 13 nitride selected from gallium nitride, aluminum nitride, indium nitride or the mixed crystals thereof. In the case that the upper surface of the layer of the crystal of the group 13 nitride is observed by cathode luminescence, the upper surface includes a linear high-luminance light-emitting part and a low-luminance light-emitting region adjacent to the high-luminance light-emitting part. A half value width of reflection at (0002) plane of an X-ray rocking curve on the upper surface is 3000 seconds or less and 20 seconds or more.
    Type: Application
    Filed: February 21, 2020
    Publication date: June 18, 2020
    Inventors: Takayuki HIRAO, Hirokazu NAKANISHI, Mikiya ICHIMURA, Takanao SHIMODAIRA, Masahiro SAKAI, Takashi YOSHINO
  • Publication number: 20190242029
    Abstract: It is provided a layer of a nitride of a group 13 element having a first main face and second main face. The layer of the nitride of the group 13 element includes a first void-depleted layer provided on the side of the first main face, a second void-depleted layer provided on the side of the second main face, and the void-distributed layer provided between the first void-depleted layer and second void-depleted layer.
    Type: Application
    Filed: April 16, 2019
    Publication date: August 8, 2019
    Applicant: NGK INSULATORS, LTD.
    Inventors: Yoshinori ISODA, Suguru NOGUCHI, Tetsuya UCHIKAWA, Takayuki HIRAO, Takanao SHIMODAIRA, Katsuhiro IMAI
  • Patent number: 10138570
    Abstract: A crystal growth apparatus includes a pressure-resistant vessel; a plurality of support tables arranged inside the pressure-resistant vessel; inner vessels each placed over the support tables, respectively; growth vessels contained the inner vessels, respectively; a heating means for heating the growth vessels; and a central rotating shaft connected to the support tables. The central rotating shaft is distant from central axes of the inner vessels, respectively. A seed crystal, a raw material of the Group 13 element and a flux are charged in each of the growth vessels, and the growth vessels are heated to form a melt and a nitrogen-containing gas is supplied to the melt to grow a crystal of a nitride of said Group 13 element while the central rotating shaft is rotated.
    Type: Grant
    Filed: May 25, 2017
    Date of Patent: November 27, 2018
    Assignee: NGK INSULATORS, LTD.
    Inventors: Takashi Yoshino, Katsuhiro Imai, Takanao Shimodaira, Takashi Wada
  • Patent number: 10041186
    Abstract: It is used a crucible containing a flux and a source material, a reaction vessel containing the crucible, an intermediate vessel containing the reaction vessel, and a pressure vessel containing the intermediate vessel and used to fill a gas comprising at least a nitrogen atom. When the flux and the source material are melted by heating to grow the nitride crystal, a vapor of an organic compound is provided in a space outside of the reaction vessel and inside of the intermediate vessel.
    Type: Grant
    Filed: August 17, 2016
    Date of Patent: August 7, 2018
    Assignee: NGK INSULATORS, LTD.
    Inventors: Katsuhiro Imai, Makoto Iwai, Masahiro Sakai, Takanao Shimodaira, Shuhei Higashihara, Takayuki Hirao
  • Patent number: 9960316
    Abstract: A composite substrate includes a sapphire substrate and a layer of a nitride of a group 13 element provided on the sapphire substrate. The layer of the nitride of the group 13 element is composed of gallium nitride, aluminum nitride or gallium aluminum nitride. The composite substrate satisfies the following formulas (1), (2) and (3). A laser light is irradiated to the composite substrate from the side of the sapphire substrate to decompose crystal lattice structure at an interface between the sapphire substrate and the layer of the nitride of the group 13 element. 5.0?(an average thickness (?m) of the layer of the nitride of the group 13 element/a diameter (mm) of the sapphire substrate)?10.0 . . . (1); 0.1? a warpage (mm) of said composite substrate×(50/a diameter (mm) of said composite substrate)2?0.6 . . . (2); 1.10?a maximum value (?m) of a thickness of said layer of said nitride of said group 13 element/a minimum value (?m) of said thickness of said layer of said nitride of said group 13 element . . .
    Type: Grant
    Filed: May 31, 2017
    Date of Patent: May 1, 2018
    Assignee: NGK INSULATORS, LTD.
    Inventors: Katsuhiro Imai, Makoto Iwai, Takanao Shimodaira
  • Publication number: 20170263810
    Abstract: A composite substrate includes a sapphire substrate and a layer of a nitride of a group 13 element provided on the sapphire substrate. The layer of the nitride of the group 13 element is composed of gallium nitride, aluminum nitride or gallium aluminum nitride. The composite substrate satisfies the following formulas (1), (2) and (3). A laser light is irradiated to the composite substrate from the side of the sapphire substrate to decompose crystal lattice structure at an interface between the sapphire substrate and the layer of the nitride of the group 13 element. 5.0?(an average thickness (?m) of the layer of the nitride of the group 13 element/a diameter (mm) of the sapphire substrate)?10.0 . . . (1); 0.1? a warpage (mm) of said composite substrate×(50/a diameter (mm) of said composite substrate)20.6 . . . (2); 1.10?a maximum value (?m) of a thickness of said layer of said nitride of said group 13 element/a minimum value (?m) of said thickness of said layer of said nitride of said group 13 element . . .
    Type: Application
    Filed: May 31, 2017
    Publication date: September 14, 2017
    Applicant: NGK INSULATORS, LTD.
    Inventors: Katsuhiro Imai, Makoto Iwai, Takanao Shimodaira
  • Publication number: 20170260644
    Abstract: A crystal growth apparatus includes a pressure-resistant vessel; a plurality of support tables arranged inside the pressure-resistant vessel; inner vessels each placed over the support tables, respectively; growth vessels contained the inner vessels, respectively; a heating means for heating the growth vessels; and a central rotating shaft connected to the support tables. The central rotating shaft is distant from central axes of the inner vessels, respectively. A seed crystal, a raw material of the Group 13 element and a flux are charged in each of the growth vessels, and the growth vessels are heated to form a melt and a nitrogen-containing gas is supplied to the melt to grow a crystal of a nitride of said Group 13 element while the central rotating shaft is rotated.
    Type: Application
    Filed: May 25, 2017
    Publication date: September 14, 2017
    Applicant: NGK INSULATORS, LTD.
    Inventors: Takashi Yoshino, Katsuhiro Imai, Takanao Shimodaira, Takashi Wada
  • Patent number: 9677192
    Abstract: A group 13 nitride crystal substrate according to the present invention is produced by growing a group 13 nitride crystal on a seed-crystal substrate by a flux method, wherein a content of inclusions in the group 13 nitride crystal grown in a region of the seed-crystal substrate except for a circumferential portion of the seed-crystal substrate, the region having an area fraction of 70% relative to an entire area of the seed-crystal substrate, is 10% or less, preferably 2% or less.
    Type: Grant
    Filed: July 15, 2011
    Date of Patent: June 13, 2017
    Assignee: NGK Insulators, Ltd.
    Inventors: Takanao Shimodaira, Katsuhiro Imai, Makoto Iwai, Takayuki Hirao
  • Publication number: 20160355945
    Abstract: It is used a crucible containing a flux and a source material, a reaction vessel containing the crucible, an intermediate vessel containing the reaction vessel, and a pressure vessel containing the intermediate vessel and used to fill a gas comprising at least a nitrogen atom. When the flux and the source material are melted by heating to grow the nitride crystal, a vapor of an organic compound is provided in a space outside of the reaction vessel and inside of the intermediate vessel.
    Type: Application
    Filed: August 17, 2016
    Publication date: December 8, 2016
    Applicant: NGK INSULATORS, LTD.
    Inventors: Katsuhiro Imai, Makoto Iwai, Masahiro Sakai, Takanao Shimodaira, Shuhei Higashihara, Takayuki Hirao
  • Patent number: 9290861
    Abstract: Regarding a base substrate, a plurality of steps are formed stepwise on the principal surface (c-face). Each step has a height difference of 10 to 40 ?m, and an edge is formed parallel to an a-face of a hexagonal crystal of GaN. Meanwhile, the terrace width of each step is set at a predetermined width. The predetermined width is set in such a way that after a GaN crystal is grown on the principal surface of the base substrate, the principal surface is covered up with grain boundaries when the grown GaN crystal is observed from the surface side. The plurality of steps can be formed through, for example, dry etching, sand blasting, lasing, and dicing.
    Type: Grant
    Filed: October 15, 2010
    Date of Patent: March 22, 2016
    Assignee: NGK INSULATORS, LTD.
    Inventors: Takayuki Hirao, Takanao Shimodaira, Katsuhiro Imai
  • Patent number: 9017479
    Abstract: The apparatus has a crucible for storing a solution; an inner container for storing a crucible; a heating container for storing the inner container, the heating container including heating elements, a container body provided with the heating elements and a lid combined with the container body; and a pressure vessel for storing the heating container and for charging an atmosphere comprising at least nitrogen gas. The lid also has a fitting surface to the container body that is inclined to a horizontal plane.
    Type: Grant
    Filed: July 29, 2008
    Date of Patent: April 28, 2015
    Assignees: NGK Insulators, Ltd., Osaka University, Toyoda Gosei Co., Ltd.
    Inventors: Makoto Iwai, Takanao Shimodaira, Takatomo Sasaki, Yusuke Mori, Fumio Kawamura, Shiro Yamasaki
  • Patent number: 8999059
    Abstract: A growth apparatus is used having a plurality of crucibles each for containing the solution, a heating element for heating the crucible, and a pressure vessel for containing at least the crucibles and the heating element and for filling an atmosphere comprising at least nitrogen gas. One seed crystal is put in each of the crucibles to grow the nitride single crystal on the seed crystal.
    Type: Grant
    Filed: September 22, 2008
    Date of Patent: April 7, 2015
    Assignees: NGK Insulators, Ltd., Osaka University
    Inventors: Katsuhiro Imai, Makoto Iwai, Takanao Shimodaira, Takatomo Sasaki, Yusuke Mori, Fumio Kawamura
  • Patent number: 8795431
    Abstract: A gallium nitride layer is produced using a seed crystal substrate by flux method. The seed crystal substrate 8A includes a supporting body 1, a plurality of seed crystal layers 4A each comprising gallium nitride single crystal and separated from one another, a low temperature buffer layer 2 provided between the seed crystal layers 4A and the supporting body and made of a nitride of a group III metal element, and an exposed layer 3 exposed to spaces between the adjacent seed crystal layers 4A and made of aluminum nitride single crystal or aluminum gallium nitride single crystal. The gallium nitride layer is grown on the seed crystal layers by flux method.
    Type: Grant
    Filed: September 20, 2013
    Date of Patent: August 5, 2014
    Assignee: NGK Insulators, Ltd.
    Inventors: Katsuhiro Imai, Makota Iwai, Takanao Shimodaira, Masahiro Sakai, Shuhei Higashihara, Takayuki Hirao
  • Patent number: 8729672
    Abstract: To grow a gallium nitride crystal, a seed-crystal substrate is first immersed in a melt mixture containing gallium and sodium. Then, a gallium nitride crystal is grown on the seed-crystal substrate under heating the melt mixture in a pressurized atmosphere containing nitrogen gas and not containing oxygen. At this time, the gallium nitride crystal is grown on the seed-crystal substrate under a first stirring condition of stirring the melt mixture, the first stirring condition being set for providing a rough growth surface, and the gallium nitride crystal is subsequently grown on the seed-crystal substrate under a second stirring condition of stirring the melt mixture, the second stirring condition being set for providing a smooth growth surface.
    Type: Grant
    Filed: April 12, 2013
    Date of Patent: May 20, 2014
    Assignee: NGK Insulators, Ltd.
    Inventors: Takanao Shimodaira, Takayuki Hirao, Katsuhiro Imai
  • Patent number: 8657955
    Abstract: It is provided a melt composition for growing a gallium nitride single crystal by flux method. The melt composition contains gallium, sodium and barium, and a content of barium is 0.05 to 0.3 mol % with respect to 100 mol % of sodium.
    Type: Grant
    Filed: August 3, 2009
    Date of Patent: February 25, 2014
    Assignees: NGK Insulators, Ltd, Osaka University, Toyoda Gosei Co., Ltd.
    Inventors: Makoto Iwai, Takanao Shimodaira, Yoshihiko Yamamura, Takatomo Sasaki, Yusuke Mori, Fumio Kawamura, Shiro Yamasaki
  • Publication number: 20140026809
    Abstract: A seed crystal substrate 10 includes a supporting body 1, and a seed crystal film 3A formed on the supporting body 1 and composed of a single crystal of a nitride of a Group 13 metal element. The seed crystal film 3A includes main body parts 3a and thin parts 3b having a thickness smaller than that of the main body parts 3a. The main body parts 3a and thin part 3b are exposed to a surface of the seed crystal substrate 10. A nitride 15 of a Group 13 metal element is grown on the seed crystal film 3A by flux method.
    Type: Application
    Filed: September 17, 2013
    Publication date: January 30, 2014
    Applicant: NGK INSULATORS, LTD.
    Inventors: Makoto Iwai, Takanao Shimodaira, Shuhei Higashihara, Takayuki Hirao, Masahiro Sakai, Katsuhiro Imai