Patents by Inventor Masakazu Katsuno

Masakazu Katsuno 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: 10711369
    Abstract: The present invention provides a method for producing an SiC single crystal, enabling obtaining an SiC single crystal substrate in which a screw dislocation-reduced region is ensured in a wide range, and an SiC single crystal substrate. The SiC single crystal substrate is produced using a seed crystal having an off angle in the off orientation from a {0001} plane by a production method wherein in advance of a growth main step of performing crystal growth to form a facet {0001} plane in the crystal peripheral part on the crystal end face having grown thereon the bulk silicon carbide single crystal and obtain more than 50% of the thickness of the obtained SiC single crystal, a growth sub-step of growing the crystal at a higher nitrogen concentration than in the growth main step and at a growth atmosphere pressure of 3.9 to 39.9 kPa and a seed crystal temperature of 2,100° C. to less than 2,300° C. is included.
    Type: Grant
    Filed: December 4, 2015
    Date of Patent: July 14, 2020
    Assignee: SHOWA DENKO K.K.
    Inventors: Shinya Sato, Tatsuo Fujimoto, Masakazu Katsuno, Hiroshi Tsuge, Masashi Nakabayashi
  • Publication number: 20200127165
    Abstract: A semiconductor light emitting device according to an embodiment includes a stacked body. The stacked body includes a first semiconductor layer of a first conductivity type, a light emitting layer is provided on the first semiconductor layer, and a second semiconductor layer of a second conductivity type provided on the light emitting layer. The stacked body includes a first protrusion on an upper surface of the stacked body. The first protrusion protrudes in a first direction from the first semiconductor layer to the light emitting layer. Length of the first protrusion in a second direction perpendicular to the first direction decreases toward the first direction. The first protrusion includes a first portion and a second portion. The first portion has a first side surface inclined with respect to the first direction. The second portion is provided below the first portion and having a second side surface inclined with respect to the first direction.
    Type: Application
    Filed: December 19, 2019
    Publication date: April 23, 2020
    Applicant: ALPAD CORPORATION
    Inventors: Go Oike, Hiroshi Katsuno, Koji Kaga, Masakazu Sawano, Yuxiong Ren, Kazuyuki Miyabe
  • Patent number: 10559716
    Abstract: A semiconductor light emitting device according to an embodiment includes a stacked body. The stacked body includes a first semiconductor layer of a first conductivity type, a light emitting layer is provided on the first semiconductor layer, and a second semiconductor layer of a second conductivity type provided on the light emitting layer. The stacked body includes a first protrusion on an upper surface of the stacked body. The first protrusion protrudes in a first direction from the first semiconductor layer to the light emitting layer. Length of the first protrusion in a second direction perpendicular to the first direction decreases toward the first direction. The first protrusion includes a first portion and a second portion. The first portion has a first side surface inclined with respect to the first direction. The second portion is provided below the first portion and having a second side surface inclined with respect to the first direction.
    Type: Grant
    Filed: March 8, 2017
    Date of Patent: February 11, 2020
    Assignee: ALPAD CORPORATION
    Inventors: Go Oike, Hiroshi Katsuno, Koji Kaga, Masakazu Sawano, Yuxiong Ren, Kazuyuki Miyabe
  • Patent number: 10403790
    Abstract: A semiconductor light-emitting device includes a light-emitting member that includes a first semiconductor layer of a first conductivity type, a second semiconductor layer of a second conductivity type, and a light-emitting layer between the first semiconductor layer and the second semiconductor layer, a first metal layer electrically connected to the first semiconductor layer, and a second metal layer electrically connected to the second semiconductor layer. The light-emitting member has a first surface including a front surface of the first semiconductor layer, a second surface including a front surface of the second semiconductor layer, a side surface including an outer periphery of the first semiconductor layer, and a recess extending inwardly of the second surface to an interior portion of the first semiconductor layer to expose an inner surface on a side of the recess facing the side surface.
    Type: Grant
    Filed: October 5, 2018
    Date of Patent: September 3, 2019
    Assignee: ALPAD CORPORATION
    Inventors: Hiroshi Katsuno, Masakazu Sawano, Kazuyuki Miyabe
  • Publication number: 20190024257
    Abstract: Provided are: a silicon carbide single crystal substrate which is cut out from a silicon carbide bulk single crystal grown by the Physical Vapor Transport method; and a process for producing the same. The number of screw dislocations in one of the semicircle areas of the substrate is smaller than that in the other thereof, namely, the number of screw dislocations in a given area of the substrate is reduced. The semicircle areas of the substrate correspond respectively to the halves of the substrate.
    Type: Application
    Filed: September 24, 2018
    Publication date: January 24, 2019
    Applicant: SHOWA DENKO K.K.
    Inventors: Shinya SATO, Tatsuo FUJIMOTO, Hiroshi TSUGE, Masakazu KATSUNO
  • Patent number: 10119200
    Abstract: Provided are: a silicon carbide single crystal substrate which is cut out from a silicon carbide bulk single crystal grown by the Physical Vapor Transport method; and a process for producing the same. The number of screw dislocations in one of the semicircle areas of the substrate is smaller than that in the other thereof, namely, the number of screw dislocations in a given area of the substrate is reduced. The semicircle areas of the substrate correspond respectively to the halves of the substrate.
    Type: Grant
    Filed: November 15, 2013
    Date of Patent: November 6, 2018
    Assignee: SHOWA DENKO K.K.
    Inventors: Shinya Sato, Tatsuo Fujimoto, Hiroshi Tsuge, Masakazu Katsuno
  • Patent number: 9915011
    Abstract: The invention provides a low resistivity silicon carbide single crystal wafer for fabricating semiconductor devices having excellent characteristics. The low resistivity silicon carbide single crystal wafer has a specific volume resistance of 0.001 ?cm to 0.012 ?cm and 90% or greater of the entire wafer surface area is covered by an SiC single crystal surface of a roughness (Ra) of 1.0 nm or less.
    Type: Grant
    Filed: December 1, 2009
    Date of Patent: March 13, 2018
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Tatsuo Fujimoto, Noboru Ohtani, Masakazu Katsuno, Masashi Nakabayashi, Hirokatsu Yashiro
  • Publication number: 20170342593
    Abstract: The present invention provides a method for producing an SiC single crystal, enabling obtaining an SiC single crystal substrate in which a screw dislocation-reduced region is ensured in a wide range, and an SiC single crystal substrate. The SiC single crystal substrate is produced using a seed crystal having an off angle in the off orientation from a {0001} plane by a production method wherein in advance of a growth main step of performing crystal growth to form a facet {0001} plane in the crystal peripheral part on the crystal end face having grown thereon the bulk silicon carbide single crystal and obtain more than 50% of the thickness of the obtained SiC single crystal, a growth sub-step of growing the crystal at a higher nitrogen concentration than in the growth main step and at a growth atmosphere pressure of 3.9 to 39.9 kPa and a seed crystal temperature of 2,100° C. to less than 2,300° C. is included.
    Type: Application
    Filed: December 4, 2015
    Publication date: November 30, 2017
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Shinya SATO, Tatsuo FUJIMOTO, Masakazu KATSUNO, Hiroshi TSUGE, Masashi NAKABAYASHI
  • Patent number: 9777403
    Abstract: A single-crystal silicon carbide and a single-crystal silicon carbide wafer of good-quality are disclosed that are low in dislocations, micropipes and other crystal defects and enable high yield and high performance when applied to a device, wherein the ratio of doping element concentrations on opposite sides in the direction of crystal growth of the interface between the seed crystal and the grown crystal is 5 or less and the doping element concentration of the grown crystal in the vicinity of the seed crystal is 2×1019 cm?3 to 6×1020 cm?3.
    Type: Grant
    Filed: October 14, 2009
    Date of Patent: October 3, 2017
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Masashi Nakabayashi, Tatsuo Fujimoto, Masakazu Katsuno, Hiroshi Tsuge
  • Patent number: 9691607
    Abstract: Disclosed is a process for producing an epitaxial single-crystal silicon carbide substrate by epitaxially growing a silicon carbide film on a single-crystal silicon carbide substrate by chemical vapor deposition. The step of crystal growth in the process comprises a main crystal growth step, which mainly occupies the period of epitaxial growth, and a secondary crystal growth step, in which the growth temperature is switched between a set growth temperature (T0) and a set growth temperature (T2) which are respectively lower and higher than a growth temperature (T1) used in the main crystal growth step. The basal plane dislocations of the single-crystal silicon carbide substrate are inhibited from being transferred to the epitaxial film. Thus, a high-quality epitaxial film is formed.
    Type: Grant
    Filed: April 7, 2011
    Date of Patent: June 27, 2017
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Takashi Aigo, Hiroshi Tsuge, Taizo Hoshino, Tatsuo Fujimoto, Masakazu Katsuno, Masashi Nakabayashi, Hirokatsu Yashiro
  • Patent number: 9234297
    Abstract: Provided are a method for manufacturing a SiC single crystal having high crystal quality and, in particular, extremely low screw dislocation density and a SiC single crystal ingot obtained by the method. In particular, provided is a silicon carbide single crystal substrate that is a substrate cut from a bulk silicon carbide single crystal grown by the Physical Vapior Transport (PVT) method, in which the screw dislocation density is smaller in the peripheral region than in the center region, so that screw dislocations are partially reduced. The method is a method for manufacturing a SiC single crystal by the PVT method using a seed crystal and the ingot is a SiC single crystal ingot obtained by the method. Particularly, the silicon carbide single crystal substrate is a silicon carbide single crystal substrate in which when, by representing the diameter of the substrate as R, a center circle region having a diameter of 0.
    Type: Grant
    Filed: August 29, 2012
    Date of Patent: January 12, 2016
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Shinya Sato, Tatsuo Fujimoto, Hiroshi Tsuge, Masakazu Katsuno
  • Publication number: 20150267319
    Abstract: Provided are: a silicon carbide single crystal substrate which is cut out from a silicon carbide bulk single crystal grown by the Physical Vapor Transport method; and a process for producing the same. The number of screw dislocations in one of the semicircle areas of the substrate is smaller than that in the other thereof, namely, the number of screw dislocations in a given area of the substrate is reduced. The semicircle areas of the substrate correspond respectively to the halves of the substrate.
    Type: Application
    Filed: November 15, 2013
    Publication date: September 24, 2015
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Shinya Sato, Tatsuo Fujimoto, Hiroshi Tsuge, Masakazu Katsuno
  • Patent number: 9068277
    Abstract: The invention provides an apparatus for manufacturing good quality single-crystal silicon carbide stably without formation of cracks and the like, which apparatus comprises: at least a crucible for accommodating silicon carbide feedstock powder and seed crystal; heat insulation material installed around the crucible; and a heating device for heating the crucible, wherein the outer profile of the crucible includes at least one region of narrower diameter than a vertically adjacent region, insulation material is also installed in the space left by the diameter difference, and thickness of the insulation material at the narrower diameter region is greater than that of the insulation material at the vertically adjacent region. The apparatus for manufacturing single-crystal silicon carbide enables precise control of the temperature gradient inside the crucible, thereby enabling manufacture of good quality single-crystal silicon carbide.
    Type: Grant
    Filed: April 1, 2009
    Date of Patent: June 30, 2015
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Masashi Nakabayashi, Tatsuo Fujimoto, Hiroshi Tsuge, Masakazu Katsuno, Noboru Ohtani
  • Patent number: 8936680
    Abstract: The present invention, which provides a crucible for producing single-crystal silicon carbide, and a production apparatus and a production method for single-crystal silicon carbide, which are capable of stably growing a single-crystal silicon carbide ingot good in crystallinity at high yield, is a crucible for producing single-crystal silicon carbide having a crucible vessel for holding silicon carbide raw material and a crucible cover for attaching a seed crystal and is adapted to sublimate a silicon carbide raw material in the crucible vessel to supply silicon carbide sublimation gas onto a seed crystal attached to the crucible cover and grow single-crystal silicon carbide on the seed crystal, which crucible for producing single-crystal silicon carbide is provided in the crucible vessel and the crucible cover with threaded portions to be screwed together and is provided with a sublimation gas discharge groove or grooves capable of regulating flow rate by relative rotation of the threaded portions; and is a
    Type: Grant
    Filed: February 25, 2010
    Date of Patent: January 20, 2015
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Masakazu Katsuno, Tatsuo Fujimoto, Hiroshi Tsuge, Masashi Nakabayashi
  • Patent number: 8927396
    Abstract: An object of the present invention is to provide a production process of an epitaxial silicon carbide single crystal substrate having a high-quality silicon carbide single crystal thin film reduced in the surface defect and the like on a silicon carbide single crystal substrate with a small off-angle. According to the present invention, in the production process of an epitaxial silicon carbide single crystal substrate having a high-quality silicon carbide single crystal thin film reduced in the surface defect and the like on a silicon carbide single crystal substrate with an off-angle of 4° or less, pretreatment etching to a depth of 0.1 to 1 ?m is performed at a temperature of 1,550 to 1,650° C. by flowing a gas containing silicon and chlorine together with a hydrogen gas such that the silicon atom concentration becomes from 0.0001 to 0.01% based on hydrogen atoms in the hydrogen gas, and thereafter, an epitaxial layer is formed.
    Type: Grant
    Filed: November 15, 2011
    Date of Patent: January 6, 2015
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Takashi Aigo, Hiroshi Tsuge, Masakazu Katsuno, Tatsuo Fujimoto, Hirokatsu Yashiro
  • Publication number: 20140363607
    Abstract: Provided are a method for manufacturing a SiC single crystal having high crystal quality and, in particular, extremely low screw dislocation density and a SiC single crystal ingot obtained by the method. In particular, provided is a silicon carbide single crystal substrate that is a substrate cut from a bulk silicon carbide single crystal grown by the Physical Vapior Transport (PVT) method, in which the screw dislocation density is smaller in the peripheral region than in the center region, so that screw dislocations are partially reduced. The method is a method for manufacturing a SiC single crystal by the PVT method using a seed crystal and the ingot is a SiC single crystal ingot obtained by the method. Particularly, the silicon carbide single crystal substrate is a silicon carbide single crystal substrate in which when, by representing the diameter of the substrate as R, a center circle region having a diameter of 0.
    Type: Application
    Filed: August 29, 2012
    Publication date: December 11, 2014
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Shinya Sato, Tatsuo Fujimoto, Hiroshi Tsuge, Masakazu Katsuno
  • Patent number: 8901570
    Abstract: Provided is an epitaxial silicon carbide single-crystal substrate in which a silicon carbide epitaxial film having excellent in-plane uniformity of doping density is disposed on a silicon carbide single-crystal substrate having an off angle that is between 1° to 6°. The epitaxial film is grown by repeating a dope layer that is 0.5 ?m or less and a non-dope layer that is 0.1 ?m or less. The dope layer is formed with the ratio of the number of carbon atoms to the number of silicon atoms (C/Si ratio) in a material gas being 1.5 to 2.0, and the non-dope layer is formed with the C/Si ratio being 0.5 or more but less than 1.5. The resulting epitaxial silicon carbide single-crystal substrate comprises a high-quality silicon carbide epitaxial film, which has excellent in-plane uniformity of doping density, on a silicon carbide single-crystal substrate having a small off angle.
    Type: Grant
    Filed: May 10, 2011
    Date of Patent: December 2, 2014
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Takashi Aigo, Hiroshi Tsuge, Taizo Hoshino, Tatsuo Fujimoto, Masakazu Katsuno, Masashi Nakabayashi, Hirokatsu Yashiro
  • Publication number: 20130320357
    Abstract: Provided are an epitaxial silicon carbide single crystal substrate having a high-quality silicon carbide single crystal thin film with less stacking faults on a silicon carbide single crystal substrate and a production method therefor. The epitaxial silicon carbide single crystal substrate is produced by growing a silicon carbide epitaxial layer on a silicon carbide single crystal substrate having an off-angle of 4° or less so that the number of stacking faults emitting light at wavelengths ranging from 400 to 600 nm by photoluminescence on the substrate is less than 10/cm2 in total. Additionally, the method for producing the epitaxial silicon carbide single crystal substrate forms the epitaxial layer by using chlorosilane as a silicon-based material gas and hydrocarbon gas as a carbon-based gas, at a growth temperature of 1600° C. to 1700° C., at a C/Si ratio of 0.5 to 1.0, and at a growth rate of 1 to 3 ?m/hr.
    Type: Application
    Filed: April 20, 2012
    Publication date: December 5, 2013
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Takashi Aigo, Hiroshi Tsuge, Masakazu Katsuno, Tatsuo Fujimoto, Hirokatsu Yashiro, Wataru Ito
  • Publication number: 20130217213
    Abstract: An object of the present invention is to provide a production process of an epitaxial silicon carbide single crystal substrate having a high-quality silicon carbide single crystal thin film reduced in the surface defect and the like on a silicon carbide single crystal substrate with a small off-angle. According to the present invention, in the production process of an epitaxial silicon carbide single crystal substrate having a high-quality silicon carbide single crystal thin film reduced in the surface defect and the like on a silicon carbide single crystal substrate with an off-angle of 4° or less, pretreatment etching to a depth of 0.1 to 1 ?m is performed at a temperature of 1,550 to 1,650° C. by flowing a gas containing silicon and chlorine together with a hydrogen gas such that the silicon atom concentration becomes from 0.0001 to 0.01% based on hydrogen atoms in the hydrogen gas, and thereafter, an epitaxial layer is formed.
    Type: Application
    Filed: November 15, 2011
    Publication date: August 22, 2013
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Takashi Aigo, Hiroshi Tsuge, Masakazu Katsuno, Tatsuo Fujimoto, Hirokatsu Yashiro
  • Publication number: 20130049014
    Abstract: Provided is an epitaxial silicon carbide single-crystal substrate in which a silicon carbide epitaxial film having excellent in-plane uniformity of doping density is disposed on a silicon carbide single-crystal substrate having an off angle that is between 1° to 6°. The epitaxial film is grown by repeating a dope layer that is 0.5 ?m or less and a non-dope layer that is 0.1 ?m or less. The dope layer is formed with the ratio of the number of carbon atoms to the number of silicon atoms (C/Si ratio) in a material gas being 1.5 to 2.0, and the non-dope layer is formed with the C/Si ratio being 0.5 or more but less than 1.5. The resulting epitaxial silicon carbide single-crystal substrate comprises a high-quality silicon carbide epitaxial film, which has excellent in-plane uniformity of doping density, on a silicon carbide single-crystal substrate having a small off angle.
    Type: Application
    Filed: May 10, 2011
    Publication date: February 28, 2013
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Takashi Aigo, Hiroshi Tsuge, Taizo Hoshino, Tatsuo Fujimoto, Masakazu Katsuno, Masashi Nakabayashi, Hirokatsu Yashiro