Patents by Inventor Tomotsugu Mitani

Tomotsugu Mitani 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: 20140077157
    Abstract: A nitride semiconductor device used chiefly as an LD and an LED element. In order to improve the output and to decrease Vf, the device is given either a three-layer structure in which a nitride semiconductor layer doped with n-type impurities serving as an n-type contact layer where an n-electrode is formed is sandwiched between undoped nitride semiconductor layers; or a superlattice structure of nitride. The n-type contact layer has a carrier concentration exceeding 3×1010 cm3, and the resistivity can be lowered below 8×10?3 ?cm.
    Type: Application
    Filed: November 22, 2013
    Publication date: March 20, 2014
    Applicant: Nichia Corporation
    Inventors: Shuji NAKAMURA, Takashi Mukai, Koji Tanizawa, Tomotsugu Mitani, Hiromitsu Marui
  • Patent number: 8592841
    Abstract: A nitride semiconductor device used chiefly as an LD and an LED element. In order to improve the output and to decrease Vf, the device is given either a three-layer structure in which a nitride semiconductor layer doped with n-type impurities serving as an n-type contact layer where an n-electrode is formed is sandwiched between undoped nitride semiconductor layers; or a superlattice structure of nitride. The n-type contact layer has a carrier concentration exceeding 3×1010 cm3, and the resistivity can be lowered below 8×10?3 ?cm.
    Type: Grant
    Filed: February 1, 2008
    Date of Patent: November 26, 2013
    Assignee: Nichia Corporation
    Inventors: Shuji Nakamura, Takashi Mukai, Koji Tanizawa, Tomotsugu Mitani, Hiroshi Marui
  • Patent number: 8076694
    Abstract: It is an object of the present invention to provide a nitride semiconductor element, which uses Si as a substrate, and whose voltage in the forward direction (Vf) is lower than in the prior art. In the nitride semiconductor element which has a nitride semiconductor layer over an Si substrate, at least a portion of the Si substrate and the nitride semiconductor layer are included in an current pass region, and the electrical conductivity type of the current pass region on the Si substrate is p-type. Furthermore, in the nitride semiconductor element which has a nitride semiconductor layer over an Si substrate, at least a portion of the Si substrate and the nitride semiconductor layer are included in an current pass region, and the majority carriers of the current pass region of the Si substrate are holes.
    Type: Grant
    Filed: April 28, 2006
    Date of Patent: December 13, 2011
    Assignee: Nichia Corporation
    Inventors: Yukio Narukawa, Tomotsugu Mitani, Masatsugu Ichikawa, Akira Kitano, Takao Misaki
  • Patent number: 7947994
    Abstract: According to the nitride semiconductor device with the active layer made of the multiple quantum well structure of the present invention, the performance of the multiple quantum well structure can be brought out to intensify the luminous output thereof thereby contributing an expanded application of the nitride semiconductor device. In the nitride semiconductor device comprises an n-region having a plurality of nitride semiconductor films, a p-region having a plurality of nitride semiconductor films, and an active layer interposed therebetween, a multi-film layer with two kinds of the nitride semiconductor films is formed in at least one of the n-region or the p-region.
    Type: Grant
    Filed: March 12, 2008
    Date of Patent: May 24, 2011
    Assignee: Nichia Corporation
    Inventors: Koji Tanizawa, Tomotsugu Mitani, Yoshinori Nakagawa, Hironori Takagi, Hiromitsu Marui, Yoshikatsu Fukuda, Takeshi Ikegami
  • Publication number: 20080191195
    Abstract: According to the nitride semiconductor device with the active layer made of the multiple quantum well structure of the present invention, the performance of the multiple quantum well structure can be brought out to intensify the luminous output thereof thereby contributing an expanded application of the nitride semiconductor device.
    Type: Application
    Filed: March 12, 2008
    Publication date: August 14, 2008
    Applicant: NICHIA CORPORATION
    Inventors: Koji TANIZAWA, Tomotsugu MITANI, Yoshinori NAKAGAWA, Hironori TAKAGI, Hiromitsu MARUI, Yoshikatsu FUKUDA, Takeshi IKEGAMI
  • Patent number: 7402838
    Abstract: According to the nitride semiconductor device with the active layer made of the multiple quantum well structure of the present invention, the performance of the multiple quantum well structure can be brought out to intensify the luminous output thereof thereby contributing an expanded application of the nitride semiconductor device. In the nitride semiconductor device comprises an n-region having a plurality of nitride semiconductor films, a p-region having a plurality of nitride semiconductor films, and an active layer interposed therebetween, a multi-film layer with two kinds of the nitride semiconductor films is formed in at least one of the n-region or the p-region.
    Type: Grant
    Filed: November 16, 2006
    Date of Patent: July 22, 2008
    Assignee: Nichia Corporation
    Inventors: Koji Tanizawa, Tomotsugu Mitani, Yoshinori Nakagawa, Hironori Takagi, Hiromitsu Marui, Yoshikatsu Fukuda, Takeshi Ikegami
  • Publication number: 20080149955
    Abstract: A nitride semiconductor device used chiefly as an LD and an LED element. In order to improve the output and to decrease Vf, the device is given either a three-layer structure in which a nitride semiconductor layer doped with n-type impurities serving as an n-type contact layer where an n-electrode is formed is sandwiched between undoped nitride semiconductor layers; or a superlattice structure of nitride. The n-type contact layer has a carrier concentration exceeding 3×1010 cm3, and the resistivity can be lowered below 8×10?3 ?cm.
    Type: Application
    Filed: February 1, 2008
    Publication date: June 26, 2008
    Applicant: Nichia Corporation
    Inventors: Shuji Nakamura, Takashi Mukai, Koji Tanizawa, Tomotsugu Mitani, Hiroshi Marui
  • Patent number: 7365369
    Abstract: A nitride semiconductor device used chiefly as an LD and an LED element. In order to improve the output and to decrease Vf, the device is given either a three-layer structure in which a nitride semiconductor layer doped with n-type impurities serving as an n-type contact layer where an n-electrode is formed is sandwiched between undoped nitride semiconductor layers; or a superlattice structure of nitride. The n-type contact layer has a carrier concentration exceeding 3×1010 cm3, and the resistivity can be lowered below 8×10?3?cm.
    Type: Grant
    Filed: July 27, 1998
    Date of Patent: April 29, 2008
    Assignee: Nichia Corporation
    Inventors: Shuji Nakamura, Takashi Mukai, Koji Tanizawa, Tomotsugu Mitani, Hiroshi Marui
  • Publication number: 20070063207
    Abstract: According to the nitride semiconductor device with the active layer made of the multiple quantum well structure of the present invention, the performance of the multiple quantum well structure can be brought out to intensify the luminous output thereof thereby contributing an expanded application of the nitride semiconductor device.
    Type: Application
    Filed: November 16, 2006
    Publication date: March 22, 2007
    Inventors: Koji Tanizawa, Tomotsugu Mitani, Yoshinori Nakagawa, Hironori Takagi, Hiromitsu Marui, Yoshikatsu Fukuda, Takeshi Ikegami
  • Patent number: 7193246
    Abstract: According to the nitride semiconductor device with the active layer made of the multiple quantum well structure of the present invention, the performance of the multiple quantum well structure can be brought out to intensify the luminous output thereof thereby contributing an expanded application of the nitride semiconductor device. In the nitride semiconductor device comprises an n-region having a plurality of nitride semiconductor films, a p-region having a plurality of nitride semiconductor films, and an active layer interposed therebetween, a multi-film layer with two kinds of the nitride semiconductor films is formed in at least one of the n-region or the p-region.
    Type: Grant
    Filed: March 10, 1999
    Date of Patent: March 20, 2007
    Assignee: Nichia Corporation
    Inventors: Koji Tanizawa, Tomotsugu Mitani, Yoshinori Nakagawa, Hironori Takagi, Hiromitsu Marui, Yoshikatsu Fukuda, Takeshi Ikegami
  • Publication number: 20060243988
    Abstract: It is an object of the present invention to provide a nitride semiconductor element, which uses Si as a substrate, and whose voltage in the forward direction (Vf) is lower than in the prior art. In the nitride semiconductor element which has a nitride semiconductor layer over an Si substrate, at least a portion of the Si substrate and the nitride semiconductor layer are included in an current pass region, and the electrical conductivity type of the current pass region on the Si substrate is p-type. Furthermore, in the nitride semiconductor element which has a nitride semiconductor layer over an Si substrate, at least a portion of the Si substrate and the nitride semiconductor layer are included in an current pass region, and the majority carriers of the current pass region of the Si substrate are holes.
    Type: Application
    Filed: April 28, 2006
    Publication date: November 2, 2006
    Inventors: Yukio Narukawa, Tomotsugu Mitani, Masatsugu Ichikawa, Akira Kitano, Takao Misaki
  • Publication number: 20030010993
    Abstract: A nitride semiconductor device used chiefly as an LD and an LED element. In order to improve the output and to decrease Vf, the device is given either a three-layer structure in which a nitride semiconductor layer doped with n-type impurities serving as an n-type contact layer where an n-electrode is formed is sandwiched between undoped nitride semiconductor layers; or a superlattice structure of nitride. The n-type contact layer has a carrier concentration exceeding 3×1010 cm 3, and the resistivity can be lowered below 8×10−3&OHgr;cm.
    Type: Application
    Filed: May 1, 2000
    Publication date: January 16, 2003
    Inventors: SHUJI NAKAMURA, TAKASHI MUKAI, KOJI TANIZAWA, TOMOTSUGU MITANI, HIROSHI MARUI
  • Patent number: 6337493
    Abstract: A nitride semiconductor device comprising an n-type nitride semiconductor layer, an active layer having a quantum well structure including a well layer of a nitride semiconductor containing In, the p-type nitride semiconductor layer having a p-type contact layer, a p-type high concentration doped layer interposed between said active layer and said p-type contact layer and a p-type multi-film layer interposed between said active layer and said p-type high concentration doped layer.
    Type: Grant
    Filed: April 20, 2000
    Date of Patent: January 8, 2002
    Assignee: Nichia Corporation
    Inventors: Koji Tanizawa, Hiroki Narimatsu, Tomoaki Sakai, Tomotsugu Mitani