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).

  • Patent number: 7352012
    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: April 20, 2006
    Date of Patent: April 1, 2008
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Yoshihiro Ueta, Takayuki Yuasa, Atsushi Ogawa, Yuhzoh Tsuda, Masahiro Araki
  • Publication number: 20070066029
    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: November 20, 2006
    Publication date: March 22, 2007
    Applicant: Sharp Kabushiki Kaisha
    Inventors: Takeshi Kamikawa, Eiji Yamada, Masahiro Araki
  • Patent number: 7157297
    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: May 10, 2005
    Date of Patent: January 2, 2007
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Takeshi Kamikawa, Eiji Yamada, Masahiro Araki
  • Publication number: 20060189012
    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: April 20, 2006
    Publication date: August 24, 2006
    Applicant: SHARP KABUSHIKI KAISHA
    Inventors: Yoshihiro Ueta, Takayuki Yuasa, Atsushi Ogawa, Yuhzoh Tsuda, Masahiro Araki
  • Patent number: 7064357
    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: January 12, 2001
    Date of Patent: June 20, 2006
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Yoshihiro Ueta, Takayuki Yuasa, Atsushi Ogawa, Yuhzoh Tsuda, Masahiro Araki
  • Publication number: 20060094244
    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: November 1, 2005
    Publication date: May 4, 2006
    Inventors: Eiji Yamada, Takeshi Kamikawa, Masahiro Araki
  • Publication number: 20060065197
    Abstract: A vapor deposition apparatus of the present invention has a substrate holder having a substrate holding surface for holding a substrate thereon, and a flow channel for supplying a source gas onto the substrate. The flow channel has an upper wall and a lower wall. An aperture portion is provided in the lower wall of the flow channel. The substrate holding surface of the substrate holder fits in the aperture portion while forming a space between the substrate holding surface and the aperture portion. A means for reducing leakage of gas through the space between the aperture portion and the substrate holder is provided. With this structure, since a means for reducing leakage of gas through the space between the aperture portion and the substrate holder is provided, the conductance with respect to outflow of gas increases, which in turn reduces variations in the amount of outflow gas. This results in high yield production of nitride semiconductor devices with a long life and high light-emission efficiency.
    Type: Application
    Filed: September 27, 2005
    Publication date: March 30, 2006
    Inventors: Eiji Yamada, Takayuki Yuasa, Masahiro Araki, Nakao Akutsu
  • Publication number: 20060057824
    Abstract: The present invention relates to an apparatus for producing a nitride semiconductor by crystal-growing the nitride semiconductor on a substrate by diffusing a gas containing a source gas of group III element and a source gas of group V element. The gas is diffused in parallel with the substrate and from upstream to downstream. The apparatus has the substrate housed in the apparatus and a flow channel for allowing the gas to flow in the flow channel. The apparatus also has a plurality of protrusions provided on an inner wall of the flow channel. A partition for causing the source gas of group III element and the source gas of group V element to be introduced separately into the flow channel is provided on the upstream portion of the flow channel and in a horizontal direction. The protrusions are formed on the upper and lower surfaces of the partition. With this structure, the source gas of group III element and the source gas of group V element are more uniformly mixed before the source gases are supplied.
    Type: Application
    Filed: September 9, 2005
    Publication date: March 16, 2006
    Inventors: Masahiro Araki, Eiji Yamada, Takayuki Yuasa, Yuhzoh Tsuda, Nakao Akutsu
  • Patent number: 7012283
    Abstract: According to an aspect of the present invention, a nitride semiconductor light emitting device includes a light emitting layer (106) having a quantum well structure with quantum well layers and barrier layers laminated alternately. The well layer is formed of a nitride semiconductor containing In, and the barrier layer is formed of a nitride semiconductor layer containing As, P or Sb. According to another aspect of the present invention, a nitride semiconductor light emitting device includes a light emitting layer having a quantum well structure with quantum well layers and barrier layers laminated alternately. The well layer is formed of GaN1?x?y?zAsxPySbz (0<x+y+z?0.3), and the barrier layer is formed of a nitride semiconductor containing In.
    Type: Grant
    Filed: September 17, 2001
    Date of Patent: March 14, 2006
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Yuhzoh Tsuda, Shigetoshi Ito, Masahiro Araki
  • Publication number: 20050250234
    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: May 10, 2005
    Publication date: November 10, 2005
    Applicant: Sharp Kabushiki Kaisha
    Inventors: Takeshi Kamikawa, Eiji Yamada, Masahiro Araki
  • Publication number: 20050025204
    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: July 30, 2004
    Publication date: February 3, 2005
    Applicant: SHARP KABUSHIKI KAISHA
    Inventors: Takeshi Kamikawa, Eiji Yamada, Masahiro Araki, Yoshika Kaneko
  • Publication number: 20040257124
    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: June 23, 2004
    Publication date: December 23, 2004
    Applicants: RENESAS TECHNOLOGY CORP., RENESAS LSI DESIGN CORPORATION
    Inventors: Masahiro Araki, Chieko Hayashi
  • Patent number: 6714060
    Abstract: In a master latch circuit, input data signal is received in a data through state and is held in a data holding state as output data signal. In a slave latch circuit, the output data signal is received in a data through state and is held and output in a data holding state. In a circuit setting control unit, in response to a clock signal, the disconnection of a first line from a power source and the connection of a second line to a ground terminal in an NMOS transistor are performed to set the master latch circuit and the slave latch circuit to the data through state and the data holding state respectively, and the connection of the first line and the disconnection of the second line are performed to change the states of the latch circuits.
    Type: Grant
    Filed: February 5, 2003
    Date of Patent: March 30, 2004
    Assignees: Renesas Technology Corp., Mitsubishi Electric System LSI Design Corporation
    Inventor: Masahiro Araki
  • Publication number: 20040027184
    Abstract: In a master latch circuit, input data signal is received in a data through state and is held in a data holding state as output data signal. In a slave latch circuit, the output data signal is received in a data through state and is held and output in a data holding state. In a circuit setting control unit, in response to a clock signal, the disconnection of a first line from a power source and the connection of a second line to a ground terminal in an NMOS transistor are performed to set the master latch circuit and the slave latch circuit to the data through state and the data holding state respectively, and the connection of the first line and the disconnection of the second line are performed to change the states of the latch circuits.
    Type: Application
    Filed: February 5, 2003
    Publication date: February 12, 2004
    Applicants: Mitsubishi Denki Kabushiki Kaisha, Mitsubishi Electric System LSI Design Corporation
    Inventor: Masahiro Araki
  • Publication number: 20040026710
    Abstract: According to an aspect of the present invention, a nitride semiconductor light emitting device includes a light emitting layer (106) having a quantum well structure with quantum well layers and barrier layers laminated alternately. The well layer is formed of a nitride semiconductor containing In, and the barrier layer is formed of a nitride semiconductor layer containing As, P or Sb. According to another aspect of the present invention, a nitride semiconductor light emitting device includes a light emitting layer having a quantum well structure with quantum well layers and barrier layers laminated alternately. The well layer is formed of GaN1-x-y-zAsxPySbz (0<x+y+z≦0.3), and the barrier layer is formed of a nitride semiconductor containing In.
    Type: Application
    Filed: March 20, 2003
    Publication date: February 12, 2004
    Inventors: Yuhzoh Tsuda, Shigetoshi Ito, Masahiro Araki
  • Patent number: 6586777
    Abstract: The present nitride semiconductor light emitting device includes a nitride semiconductor thick film substrate and a light emitting layered structure including a plurality of nitride semiconductor layers stacked on the substrate. The nitride semiconductor substrate includes at least two layer regions including a first layer region of a high impurity concentration and a second layer region of an impurity concentration lower than the first layer region. The light emitting layered structure is formed on the first layer region of the substrate.
    Type: Grant
    Filed: August 18, 2000
    Date of Patent: July 1, 2003
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Takayuki Yuasa, Atsushi Ogawa, Masahiro Araki, Yoshihiro Ueta, Yuhzoh Tsuda, Mototaka Taneya
  • Patent number: 6455877
    Abstract: A GaN light-emitting device is provided having a low specific contact resistance of an n-type electrode as well as a low threshold voltage or threshold current density. The GaN light-emitting device has an electrode formed on a nitrogen-terminated surface of a GaN substrate. Specifically, the GaN light-emitting device includes the GaN substrate, a plurality of GaN compound semiconductor layers formed on the GaN substrate, and the n-type electrode and a p-type electrode, wherein the semiconductor substrate is of n-type and the n-type electrode is formed on the nitrogen-terminated surface of the semiconductor substrate. The concentration of n-type impurities in the substrate preferably ranges from 1×1017 cm−3 to 1×1021 cm−3.
    Type: Grant
    Filed: September 8, 2000
    Date of Patent: September 24, 2002
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Atsushi Ogawa, Takayuki Yuasa, Yoshihiro Ueta, Yuhzoh Tsuda, Masahiro Araki, Mototaka Taneya
  • Publication number: 20010030329
    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: January 12, 2001
    Publication date: October 18, 2001
    Inventors: Yoshihiro Ueta, Takayuki Yuasa, Atsushi Ogawa, Yuhzoh Tsuda, Masahiro Araki