Patents by Inventor Yoshinao Kumagai

Yoshinao Kumagai 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: 9611545
    Abstract: A ZnO film production method includes: disposing a substrate on an installation base; and, while supplying chlorine gas from a chlorine gas supply source to a first raw material storing part R1 and supplying oxygen gas from a third gas supply source (oxygen gas supply source) G3 into a reaction container, controlling heating units (heaters H1, H2 and H3) with a control device CONT such that temperature T1 of the first raw material storing part R1, temperature T2 of a second raw material storing part R2 and temperature T3 of the installation base on which the substrate is disposed satisfy a relationship of T1<T2<T3. Thus, according to the production method of the present disclosure, it is possible to produce a high-quality ZnO film.
    Type: Grant
    Filed: June 19, 2013
    Date of Patent: April 4, 2017
    Assignee: TOKYO ELECTRON LIMITED
    Inventors: Song yun Kang, Yoshinao Kumagai, Akinori Koukitu
  • Publication number: 20160265137
    Abstract: As one embodiment, the present invention provides a method for growing a ?-Ga2O3-based single crystal film by using HVPE method. The method includes a step of exposing a Ga2O3-based substrate to a gallium chloride-based gas and an oxygen-including gas, and growing a ?-Ga2O3-based single crystal film on a principal surface of the Ga2O3-based substrate at a growth temperature of not lower than 900° C.
    Type: Application
    Filed: September 18, 2014
    Publication date: September 15, 2016
    Inventors: Ken GOTO, Kohei SASAKI, Akinori KOUKITU, Yoshinao KUMAGAI, Hisashi MURAKAMI
  • Publication number: 20160186361
    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: Application
    Filed: March 8, 2016
    Publication date: June 30, 2016
    Inventors: Akinori KOUKITU, Yoshinao KUMAGAI, Hisashi MURAKAMI
  • Publication number: 20160108554
    Abstract: The method for manufacturing an aluminum-based group III nitride single crystal includes the step of supplying an aluminum halide gas and a nitrogen source gas onto a base substrate, such that a reaction of the aluminum halide gas and the nitrogen source gas is conducted on the base substrate, wherein the reaction of the aluminum halide gas and the nitrogen source gas is conducted under coexistence of a halogen-based gas such that a halogen-based gas ratio (H) represented by the following formula (1) is no less than 0.1 and less than 1.0: H=VH/I(VH+VAl)??(1) (In the formula (1), VH represents a supply of the halogen-based gas; and VAl represents a supply of the aluminum halide gas); and a growth rate of the aluminum-based group III nitride single crystal is no less than 10 ?m/h.
    Type: Application
    Filed: June 10, 2014
    Publication date: April 21, 2016
    Inventors: Akinori KOUKITSU, Yoshinao KUMAGAI, Toru NAGASHIMA, Reiko OKAYAMA
  • Patent number: 9281180
    Abstract: According to the invention, there is provided a method for producing a gallium trichloride gas, the method including: a first step of reacting a metallic gallium and a chlorine gas to produce a gallium monochloride gas; and a second step of reacting the produced gallium monochloride gas and a chlorine gas to produce a gallium trichloride gas.
    Type: Grant
    Filed: May 11, 2011
    Date of Patent: March 8, 2016
    Assignee: National University Corporation Tokyo University of Agriculture
    Inventors: Akinori Koukitu, Yoshinao Kumagai
  • Publication number: 20150247260
    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 A1N 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: Application
    Filed: August 23, 2012
    Publication date: September 3, 2015
    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: 20150225846
    Abstract: A ZnO film production method includes: disposing a substrate on an installation base; and, while supplying chlorine gas from a chlorine gas supply source to a first raw material storing part R1 and supplying oxygen gas from a third gas supply source (oxygen gas supply source) G3 into a reaction container, controlling heating units (heaters H1, H2 and H3) with a control device CONT such that temperature T1 of the first raw material storing part R1, temperature T2 of a second raw material storing part R2 and temperature T3 of the installation base on which the substrate is disposed satisfy a relationship of T1<T2<T3. Thus, according to the production method of the present disclosure, it is possible to produce a high-quality ZnO film.
    Type: Application
    Filed: June 19, 2013
    Publication date: August 13, 2015
    Inventors: Song yun Kang, Yoshinao Kumagai, Akinori Koukitu
  • Patent number: 8926752
    Abstract: There is provided a method capable of obtaining an aluminum-based group III nitride crystal layer having a smooth surface and high crystallinity by employing only HVPE in which inexpensive raw materials can be used to reduce production costs and high-speed film formation is possible without employing MOVPE. To produce a group III nitride crystal by HVPE comprising the step of growing a group III nitride crystal layer by vapor-phase growth on a single crystal substrate by contacting the heated single crystal substrate with a raw material gas containing a group III halide and a compound having a nitrogen atom, the group III nitride crystal is grown by vapor-phase growth on the single crystal substrate heated at a temperature of 1,000° C. or more and less than 1,200° C. to form an intermediate layer and then, a group III nitride crystal is further grown by vapor-phase growth on the intermediate layer on the substrate heated at a temperature of 1,200° C. or higher.
    Type: Grant
    Filed: February 27, 2008
    Date of Patent: January 6, 2015
    Assignees: Tokuyama Corporation, Tokyo University of Agriculture and Technology
    Inventors: Akinori Koukitu, Yoshinao Kumagai, Toru Nagashima, Kazuya Takada, Hiroyuki Yanagi
  • Publication number: 20140346638
    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: Application
    Filed: December 22, 2011
    Publication date: November 27, 2014
    Applicants: TOKUYAMA CORPORATION, C/O NATIONAL UNIVERSITY CORPORATION TOKYO
    Inventors: Akinori Koukitu, Yoshinao Kumagai, Toru Nagashima, Yuki Hiraren
  • Patent number: 8822263
    Abstract: It is provided a hetero epitaxial growth method, a hetero epitaxial crystal structure, a hetero epitaxial growth apparatus and a semiconductor device, the method includes forming a buffer layer formed with the orienting film of an oxide, or the orienting film of nitride on a heterogeneous substrate; and performing crystal growth of a zinc oxide based semiconductor layer on the buffer layer using a halogenated group II metal and an oxygen material. It is provided a homo epitaxial growth method, a homo epitaxial crystal structure, a homo epitaxial growth apparatus and a semiconductor device, the homo epitaxial growth method includes introducing reactant gas mixing zinc containing gas and oxygen containing gas on a zinc oxide substrate; and performing crystal growth of a zinc oxide based semiconductor layer on the zinc oxide substrate.
    Type: Grant
    Filed: June 29, 2009
    Date of Patent: September 2, 2014
    Assignees: National University Corporation Tokyo University of Agriculture and Technology, Rohm Co., Ltd., Tokyo Electron Limited
    Inventors: Akinori Koukitu, Yoshinao Kumagai, Tetsuo Fujii, Naoki Yoshii
  • Publication number: 20140103356
    Abstract: InGaN-based light-emitting devices fabricated on an InGaN template layer are disclosed.
    Type: Application
    Filed: October 15, 2013
    Publication date: April 17, 2014
    Applicant: SORAA, INC.
    Inventors: Michael R. KRAMES, Mark P. D'EVELYN, Akinori KOUKITU, Yoshinao KUMAGAI, Hisashi MURAKAMI
  • Publication number: 20130130477
    Abstract: According to the invention, there is provided a method for producing a gallium trichloride gas, the method including: a first step of reacting a metallic gallium and a chlorine gas to produce a gallium monochloride gas; and a second step of reacting the produced gallium monochloride gas and a chlorine gas to produce a gallium trichloride gas.
    Type: Application
    Filed: May 11, 2011
    Publication date: May 23, 2013
    Applicant: National University Corporation Tokyo University of Agriculture and Technology
    Inventors: Akinori Koukuti, Yoshinao Kumagai
  • Patent number: 8129208
    Abstract: This invention provides a self supporting substrate which consists of a n-type conductive aluminum nitride semiconductor crystal and is useful for manufacturing the vertical conductive type AlN semiconductor device. The n-type conductive aluminum nitride semiconductor crystal, by which the self supporting substrate is made up, contains Si atom at a concentration of 1×1018 to 5×1020 cm?3 is substantially free of halogen atoms and substantially does not absorb the light having the energy of not more than 5.9 eV. The self supporting substrate can be obtained by a method comprising the steps of forming an AlN crystal layer on a single crystal substrate such as a sapphire by the HVPE method, preheating the obtained substrate having the AlN crystal layer to a temperature of 1,200° C. or more, forming a second layer consisting of the n-type conductive aluminum nitride semiconductor crystal is formed on the AlN crystal layer in high rate by the HVPE method and separating the second layer from the obtained laminate.
    Type: Grant
    Filed: February 2, 2008
    Date of Patent: March 6, 2012
    Assignees: Tokuyama Corporation, Tokyo University of Agriculture and Technology
    Inventors: Akinori Koukitu, Yoshinao Kumagai, Toru Nagashima, Kazuya Takada, Hiroyuki Yanagi
  • Publication number: 20110094438
    Abstract: The present invention provides a self-supporting substrate obtained by the steps of: forming an Al-based group-III nitride thin-layer having a thickness in the range of 3-200 nm on a base substrate made of a single crystal of an inorganic substance which substantially does not decompose at 800° C. in an inert gas atmosphere and which does produce volatiles by decomposition when contacting with a reducing gas in a temperature range of 800-1600° C., for example sapphire; forming voids along the interface between the base substrate and the Al-based group-III nitride thin-layer of the obtained laminated substrate by thermally treating the laminated substrate in a temperature range of 800-1600° C. in a reducing gas atmosphere containing ammonia gas; forming a group-III nitride single crystal thick-layer on the Al-based group-III nitride thin-layer; and separating these formed layers.
    Type: Application
    Filed: January 9, 2009
    Publication date: April 28, 2011
    Inventors: Akinori Koukitu, Yoshinao Kumagai, Masanari Ishizuki, Toru Nagashima, Akira Hakomori, Kazuya Takada
  • Patent number: 7915149
    Abstract: There is disclosed a method for forming a gallium nitride layer of which resistivity is 1×106 ?·cm or more, including steps of: forming a gallium nitride layer containing iron on a substrate; and heating said gallium nitride layer formed on said substrate.
    Type: Grant
    Filed: June 10, 2008
    Date of Patent: March 29, 2011
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Seiji Nakahata, Fumitaka Sato, Yoshiki Miura, Akinori Koukitu, Yoshinao Kumagai
  • Publication number: 20110018104
    Abstract: The present invention is a method for producing a laminated body, comprising the steps of: (1) preparing a base substrate having a surface formed of a single crystal which is different from the material constituting the Al-based group-III nitride single crystal layer to be formed; (2) forming an Al-based group-III nitride single crystal layer having a thickness of 10 nm to 1.5 ?m on the single crystal surface of the prepared base substrate; (3) forming on the Al-based group-III nitride single crystal layer a non-single crystal layer being 100 times or more thicker than the Al-based group-III nitride single crystal layer without breaking the previously-obtained Al-based group-III nitride single crystal layer; and (4) removing the base substrate.
    Type: Application
    Filed: December 16, 2008
    Publication date: January 27, 2011
    Inventors: Toru Nagashima, Akira Hakomori, Kazuya Takada, Masanari Ishizuki, Akinori Koukitu, Yoshinao Kumagai
  • Publication number: 20100320462
    Abstract: This invention provides a selfsupporting substrate which consists of a n-type conductive aluminum nitride semiconductor crystal and is useful for manufacturing the vertical conductive type AlN semiconductor device. The n-type conductive aluminum nitride semiconductor crystal, by which the selfsupporting substrate is made up, contains Si atom at a concentration of 1×1018 to 5×1020 cm?3, is substantially free from halogen atoms, and substantially does not absorb the light having the energy of not more than 5.9 eV. The selfsupporting substrate can be obtained by a method comprising the steps of forming an AlN crystal layer on a single crystal substrate such as a sapphire by the HVPE method, preheating the obtained substrate having the AlN crystal layer to a temperature of 1,200° C. or more, forming a second layer consisting of the n-type conductive aluminum nitride semiconductor crystal is formed on the AlN crystal layer in high rate by the HVPE method and separating the second layer from the obtained laminate.
    Type: Application
    Filed: February 2, 2008
    Publication date: December 23, 2010
    Inventors: Akinori Koukitu, Yoshinao Kumagai, Toru Nagashima, Kazuya Takada, Hiroyuki Yanagi
  • Patent number: 7843040
    Abstract: A method of forming an iron-doped gallium nitride for a semi-insulating GaN substrate is provided. A substrate (1), such as a (0001)-cut sapphire substrate, is placed on a susceptor of a metalorganic hydrogen chloride vapor phase apparatus (11). Next, gaseous iron compound GFe from a source (13) for an iron compound, such as ferrocene, and hydrogen chloride gas G1HCl from a hydrogen chloride source (15) are caused to react with each other in a mixing container (16) to generate gas GFeComp of an iron-containing reaction product, such as iron chloride (FeCl2). In association with the generation, the iron-containing reaction product GFeComp, first substance gas GN containing elemental nitrogen from a nitrogen source (17), and second substance gas GGa containing elemental gallium are supplied to a reaction tube (21) to form iron-doped gallium nitride (23) on the substrate (1).
    Type: Grant
    Filed: December 2, 2008
    Date of Patent: November 30, 2010
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Akinori Koukitu, Yoshinao Kumagai, Yoshiki Miura, Kikurou Takemoto, Fumitaka Sato
  • Publication number: 20100093124
    Abstract: There is provided a method capable of obtaining an aluminum-based group III nitride crystal layer having a smooth surface and high crystallinity by employing only HVPE in which inexpensive raw materials can be used to reduce production costs and high-speed film formation is possible without employing MOVPE. To produce a group III nitride crystal by HVPE comprising the step of growing a group III nitride crystal layer by vapor-phase growth on a single crystal substrate by contacting the heated single crystal substrate with a raw material gas containing a group III halide and a compound having a nitrogen atom, the group III nitride crystal is grown by vapor-phase growth on the single crystal substrate heated at a temperature of 1,000° C. or more and less than 1,200° C. to form an intermediate layer and then, a group III nitride crystal is further grown by vapor-phase growth on the intermediate layer on the substrate heated at a temperature of 1,200° C. or higher.
    Type: Application
    Filed: February 27, 2008
    Publication date: April 15, 2010
    Inventors: Akinori Koukitu, Yoshinao Kumagai, Toru Nagashima, Kazuya Takada, Hiroyuki Yanagi
  • Publication number: 20100006836
    Abstract: It is provided a hetero epitaxial growth method, a hetero epitaxial crystal structure, a hetero epitaxial growth apparatus and a semiconductor device, the method includes forming a buffer layer formed with the orienting film of an oxide, or the orienting film of nitride on a heterogeneous substrate; and performing crystal growth of a zinc oxide based semiconductor layer on the buffer layer using a halogenated group II metal and an oxygen material. It is provided a homo epitaxial growth method, a homo epitaxial crystal structure, a homo epitaxial growth apparatus and a semiconductor device, the homo epitaxial growth method includes introducing reactant gas mixing zinc containing gas and oxygen containing gas on a zinc oxide substrate; and performing crystal growth of a zinc oxide based semiconductor layer on the zinc oxide substrate.
    Type: Application
    Filed: June 29, 2009
    Publication date: January 14, 2010
    Applicants: Natinal University Corporation Tokyo University of Agriculture and Technology, ROHM CO., LTD., TOKYO ELECTRON LIMITED
    Inventors: Akinori Koukitu, Yoshinao Kumagai, Tetsuo Fujii, Naoki Yoshii