Patents by Inventor Masahiro Araki

Masahiro Araki 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: 20150002219
    Abstract: A semiconductor device containing a terminal, a power supply voltage dropping circuit that generates a constant voltage, a switch circuit to periodically apply a constant voltage to a terminal in response to a first clock, a current-controlled oscillator circuit, and a counter, and in which the power supply voltage dropping circuit supplies a first current to the switch circuit, the current-controlled oscillator circuit generates a second clock whose frequency changes in response to the value of the first current, and the counter counts the number of second clocks within the counting time.
    Type: Application
    Filed: May 27, 2014
    Publication date: January 1, 2015
    Applicant: RENESAS ELECTRONICS CORPORATION
    Inventor: Masahiro ARAKI
  • Patent number: 8866153
    Abstract: Provided is a functional element which is obtained by forming a lamination film on a substrate and then dividing the substrate and the lamination film into a desired shape. The functional element has a hexagonal substrate, a lamination film formed on a C surface of the substrate, and a plurality of divided surfaces which are exposed by dividing the substrate into quadrilaterals. At least one line of division lines in the case of dividing the substrate into quadrilaterals is perpendicular to any one of equivalent directions of [1-100], [?1010], and [01-01] of the substrate from a [0001] direction of the substrate, and the divided surfaces formed by the division lines are inclined in a direction of other divided surfaces to which at least a part thereof is opposed.
    Type: Grant
    Filed: January 18, 2011
    Date of Patent: October 21, 2014
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Akihiro Urata, Masahiro Araki, Takaaki Utsumi, Masahiro Shiota
  • Patent number: 8647904
    Abstract: Provided is a method for manufacturing a nitride semiconductor device, including the steps of: forming an AlNO buffer layer containing at least aluminum, nitrogen, and oxygen on a substrate; and forming a nitride semiconductor layer on the AlNO buffer layer, wherein, in the step of forming the AlNO buffer layer, the AlNO buffer layer is formed by a reactive sputtering method using aluminum as a target in an atmosphere to and from which nitrogen gas and oxygen gas are continuously introduced and exhausted, and the atmosphere is an atmosphere in which a ratio of a flow rate of the oxygen gas to a sum of a flow rate of the nitrogen gas and the flow rate of the oxygen gas is not more than 0.5%.
    Type: Grant
    Filed: February 23, 2011
    Date of Patent: February 11, 2014
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Masahiro Araki, Takaaki Utsumi, Masahiko Sakata
  • Publication number: 20130277684
    Abstract: A nitride semiconductor structure in which a first nitride semiconductor underlying layer is provided on a substrate having a recess portion and a projection portion provided between the recess portions at a surface thereof, the first nitride semiconductor underlying layer has at least 6 first oblique facet planes surrounding the projection portion on an outer side of the projection portion, and a second nitride semiconductor underlying layer buries the first oblique facet planes, a nitride semiconductor light emitting element, a nitride semiconductor transistor element, a method of manufacturing a nitride semiconductor structure, and a method of manufacturing a nitride semiconductor element are provided.
    Type: Application
    Filed: December 21, 2011
    Publication date: October 24, 2013
    Inventors: Masahiro Araki, Shinya Yoshida, Haruhisa Takiguchi, Atsushi Ogawa, Takao Kinoshita, Tohru Murata, Takeshi Funaki, Masayuki Hoteida
  • Publication number: 20130161640
    Abstract: A nitride semiconductor device is provided that prevents development of cracks, that has nitride semiconductor thin films with uniform thicknesses and good growth surface flatness, and is thus consistent in characteristics, and that can be fabricated at a satisfactory yield. In this nitride semiconductor device, the nitride semiconductor thin films are grown on a substrate having an off-angle between a direction normal to the surface of ridges and the crystal direction <0001>. This helps either reduce or intentionally promote diffusion or movement of the atoms or molecules of a source material of the nitride semiconductor thin films through migration thereof. As a result, a nitride semiconductor growth layer with good surface flatness can be formed, and thus a nitride semiconductor device with satisfactory characteristics can be obtained.
    Type: Application
    Filed: December 26, 2012
    Publication date: June 27, 2013
    Applicant: Sharp Kabushiki Kaisha
    Inventors: Eiji Yamada, Takeshi Kamikawa, Masahiro Araki
  • Patent number: 8368183
    Abstract: A nitride semiconductor device is provided that prevents development of cracks, that has nitride semiconductor thin films with uniform thicknesses and good growth surface flatness, and is thus consistent in characteristics, and that can be fabricated at a satisfactory yield. In this nitride semiconductor device, the nitride semiconductor thin films are grown on a substrate having an off-angle between a direction normal to the surface of ridges and the crystal direction <0001>. This helps either reduce or intentionally promote diffusion or movement of the atoms or molecules of a source material of the nitride semiconductor thin films through migration thereof. As a result, a nitride semiconductor growth layer with good surface flatness can be formed, and thus a nitride semiconductor device with satisfactory characteristics can be obtained.
    Type: Grant
    Filed: November 1, 2005
    Date of Patent: February 5, 2013
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Eiji Yamada, Takeshi Kamikawa, Masahiro Araki
  • Patent number: 8350609
    Abstract: The present invention provides a semiconductor device in which an adjustable range of a resistance value of a variable resistance circuit is large. The semiconductor device has an output buffer including a plurality of sets of resistance elements and a plurality of sets of transistors, a plurality of replica circuits, and a plurality of sets of operational amplifiers, and drain currents of the plurality of sets of transistors are adjusted so that output impedances of the output buffer become predetermined values. Therefore, even in the case where the resistance values of the resistance elements largely fluctuate due to fluctuations in manufacture process and the like, the output impedances can be set to predetermined values.
    Type: Grant
    Filed: February 8, 2012
    Date of Patent: January 8, 2013
    Assignee: Renesas Electronics Corporation
    Inventors: Masahiro Araki, Atsuhiko Ishibashi
  • Publication number: 20120319162
    Abstract: Provided is a method for manufacturing a nitride semiconductor device, including the steps of: forming an AlNO buffer layer containing at least aluminum, nitrogen, and oxygen on a substrate; and forming a nitride semiconductor layer on the AlNO buffer layer, wherein, in the step of forming the AlNO buffer layer, the AlNO buffer layer is formed by a reactive sputtering method using aluminum as a target in an atmosphere to and from which nitrogen gas and oxygen gas are continuously introduced and exhausted, and the atmosphere is an atmosphere in which a ratio of a flow rate of the oxygen gas to a sum of a flow rate of the nitrogen gas and the flow rate of the oxygen gas is not more than 0.5%.
    Type: Application
    Filed: February 23, 2011
    Publication date: December 20, 2012
    Applicant: Sharp Kabushiki Kaisha
    Inventors: Masahiro Araki, Takaaki Utsumi, Masahiko Sakata
  • Publication number: 20120292642
    Abstract: Provided is a functional element which is obtained by forming a lamination film on a substrate and then dividing the substrate and the lamination film into a desired shape. The functional element has a hexagonal substrate, a lamination film formed on a C surface of the substrate, and a plurality of divided surfaces which are exposed by dividing the substrate into quadrilaterals. At least one line of division lines in the case of dividing the substrate into quadrilaterals is perpendicular to any one of equivalent directions of [1-100], [-1010], and [01-01] of the substrate from a [0001] direction of the substrate, and the divided surfaces formed by the division lines are inclined in a direction of other divided surfaces to which at least a part thereof is opposed.
    Type: Application
    Filed: January 18, 2011
    Publication date: November 22, 2012
    Applicant: Sharp Kabushiki Kaisha
    Inventors: Akihiro Urata, Masahiro Araki, Takaaki Utsumi, Masahiro Shiota
  • Patent number: 8288794
    Abstract: On a processed substrate having an engraved region as a depressed portion formed thereon, a nitride semiconductor thin film is laid. The sectional area occupied by the nitride semiconductor thin film filling the depressed portion is 0.8 times the sectional area of the depressed portion or less.
    Type: Grant
    Filed: June 10, 2010
    Date of Patent: October 16, 2012
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Takeshi Kamikawa, Eiji Yamada, Masahiro Araki
  • Publication number: 20120229197
    Abstract: The present invention provides a semiconductor device in which an adjustable range of a resistance value of a variable resistance circuit is large. The semiconductor device has an output buffer including a plurality of sets of resistance elements and a plurality of sets of transistors, a plurality of replica circuits, and a plurality of sets of operational amplifiers, and drain currents of the plurality of sets of transistors are adjusted so that output impedances of the output buffer become predetermined values. Therefore, even in the case where the resistance values of the resistance elements largely fluctuate due to fluctuations in manufacture process and the like, the output impedances can be set to predetermined values.
    Type: Application
    Filed: February 8, 2012
    Publication date: September 13, 2012
    Inventors: Masahiro ARAKI, Atsuhiko Ishibashi
  • Patent number: 8030110
    Abstract: A nitride semiconductor laser device uses a substrate with low defect density, contains reduced strains inside a nitride semiconductor film, and thus offers a satisfactorily long useful life. On a GaN substrate (10) with a defect density as low as 106 cm?2 or less, a stripe-shaped depressed portion (16) is formed by etching. On this substrate (10), a nitride semiconductor film (11) is grown, and a laser stripe (12) is formed off the area right above the depressed portion (16). With this structure, the laser stripe (12) is free from strains, and the semiconductor laser device offers a long useful life. Moreover, the nitride semiconductor film (11) develops reduced cracks, resulting in a greatly increased yield rate.
    Type: Grant
    Filed: December 27, 2010
    Date of Patent: October 4, 2011
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Takeshi Kamikawa, Eiji Yamada, Masahiro Araki, Yoshika Kaneko
  • Publication number: 20110136276
    Abstract: A nitride semiconductor laser device uses a substrate with low defect density, contains reduced strains inside a nitride semiconductor film, and thus offers a satisfactorily long useful life. On a GaN substrate (10) with a defect density as low as 106 cm?2 or less, a stripe-shaped depressed portion (16) is formed by etching. On this substrate (10), a nitride semiconductor film (11) is grown, and a laser stripe (12) is formed off the area right above the depressed portion (16). With this structure, the laser stripe (12) is free from strains, and the semiconductor laser device offers a long useful life. Moreover, the nitride semiconductor film (11) develops reduced cracks, resulting in a greatly increased yield rate.
    Type: Application
    Filed: December 27, 2010
    Publication date: June 9, 2011
    Applicant: SHARP KABUSHIKI KAISHA
    Inventors: Takeshi KAMIKAWA, Eiji Yamada, Masahiro Araki, Yoshika Kaneko
  • Publication number: 20110062016
    Abstract: There is provided a method for manufacturing an aluminum-containing nitride intermediate layer, a method for manufacturing a nitride layer, and a method for manufacturing a nitride semiconductor element by using the nitride layer, in which at least one of the following conditions (i) to (iii) is employed during stacking of the aluminum-containing nitride intermediate layer by using a DC magnetron sputtering method in which a voltage is applied by means of a DC-continuous scheme. (i) The shortest distance between a center of a surface of a target and a growth surface of a substrate is set to 100 mm or more and 250 mm or less. (ii) Nitrogen gas is used as gas supplied to a DC magnetron sputtering apparatus. (iii) The target is inclined with respect to the growth surface of the substrate.
    Type: Application
    Filed: August 11, 2010
    Publication date: March 17, 2011
    Applicant: Sharp Kabushiki Kaisha
    Inventors: Masahiro ARAKI, Takaaki Utsumi, Masahiko Sakata
  • Patent number: 7903708
    Abstract: A nitride semiconductor laser device uses a substrate with low defect density, contains reduced strains inside a nitride semiconductor film, and thus offers a satisfactorily long useful life. On a GaN substrate (10) with a defect density as low as 106 cm?2 or less, a stripe-shaped depressed portion (16) is formed by etching. On this substrate (10), a nitride semiconductor film (11) is grown, and a laser stripe (12) is formed off the area right above the depressed portion (16). With this structure, the laser stripe (12) is free from strains, and the semiconductor laser device offers a long useful life. Moreover, the nitride semiconductor film (11) develops reduced cracks, resulting in a greatly increased yield rate.
    Type: Grant
    Filed: July 30, 2004
    Date of Patent: March 8, 2011
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Takeshi Kamikawa, Eiji Yamada, Masahiro Araki, Yoshika Kaneko
  • Publication number: 20100244046
    Abstract: On a processed substrate having an engraved region as a depressed portion formed thereon, a nitride semiconductor thin film is laid. The sectional area occupied by the nitride semiconductor thin film filling the depressed portion is 0.8 times the sectional area of the depressed portion or less.
    Type: Application
    Filed: June 10, 2010
    Publication date: September 30, 2010
    Applicant: Sharp Kabushiki Kaisha
    Inventors: Takeshi Kamikawa, Eiji Yamada, Masahiro Araki
  • Patent number: 7772611
    Abstract: On a processed substrate having an engraved region as a depressed portion formed thereon, a nitride semiconductor thin film is laid. The sectional area occupied by the nitride semiconductor thin film filling the depressed portion is 0.8 times the sectional area of the depressed portion or less.
    Type: Grant
    Filed: November 20, 2006
    Date of Patent: August 10, 2010
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Takeshi Kamikawa, Eiji Yamada, Masahiro Araki
  • Patent number: 7663158
    Abstract: A nitride compound semiconductor light emitting device includes: a GaN substrate having a crystal orientation which is tilted away from a <0001> direction by an angle which is equal to or greater than about 0.05° and which is equal to or less than about 2°, and a semiconductor multilayer structure formed on the GaN substrate, wherein the semiconductor multilayer structure includes: an acceptor doping layer containing a nitride compound semiconductor; and an active layer including a light emitting region.
    Type: Grant
    Filed: November 16, 2007
    Date of Patent: February 16, 2010
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Yoshihiro Ueta, Takayuki Yuasa, Atsushi Ogawa, Yuhzoh Tsuda, Masahiro Araki
  • Publication number: 20090141774
    Abstract: In a spread spectrum clock generator, a DLL circuit delays an oscillation clock signal from a VCO and outputs ten delay clock signals having different phases respectively. A selector selects any one of the ten delay clock signals, and outputs a selected clock signal. A control circuit controls a signal selection operation of the selector. A feedback frequency divider divides a frequency of the selected clock signal by a frequency division ratio N, and generates a comparison clock signal. In this manner, a phase of the comparison clock signal can be fine-tuned. Therefore, a spread spectrum clock generator capable of frequency modulation with high accuracy can be obtained.
    Type: Application
    Filed: February 4, 2009
    Publication date: June 4, 2009
    Applicants: RENESAS TECHNOLOGY CORP, RENESAS LSI DESIGN CORPORATION
    Inventors: Masahiro ARAKI, Chieko Hayashi
  • Publication number: 20080087905
    Abstract: A nitride compound semiconductor light emitting device includes: a GaN substrate having a crystal orientation which is tilted away from a <0001> direction by an angle which is equal to or greater than about 0.05° and which is equal to or less than about 2°, and a semiconductor multilayer structure formed on the GaN substrate, wherein the semiconductor multilayer structure includes: an acceptor doping layer containing a nitride compound semiconductor; and an active layer including a light emitting region.
    Type: Application
    Filed: November 16, 2007
    Publication date: April 17, 2008
    Applicant: SHARP KABUSHIKI KAISHA
    Inventors: Yoshihiro UETA, Takayuki YUASA, Atsushi OGAMA, Yuhzoh TSUDA, Masahiro ARAKI