Patents by Inventor Koji Tanizawa

Koji Tanizawa 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: 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
  • Patent number: 7348602
    Abstract: The present invention provides a nitride semiconductor light emitting device with an active layer of the multiple quantum well structure, in which the device has an improved luminous intensity and a good electrostatic withstanding voltage, thereby allowing the expanded application to various products. The active layer 7 is formed of a multiple quantum well structure containing InaGa1?aN (0?a<1). The p-cladding layer 8 is formed on said active layer containing the p-type impurity. The p-cladding layer 8 is mode of a multi-film layer including a first nitride semiconductor film containing Al and a second nitride semiconductor film having a composition different from that of said first nitride semiconductor film. Alternatively, the p-cladding layer 8 is made of single-layered layer made of AlbGa1?bN (0?b?1). A low-doped layer 9 is grown on the p-cladding layer 8 having a p-type impurity concentration lower than that of the p-cladding layer 8.
    Type: Grant
    Filed: October 18, 2004
    Date of Patent: March 25, 2008
    Assignee: Nichia Corporation
    Inventor: Koji Tanizawa
  • 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: 20050145860
    Abstract: The present invention provides a nitride semiconductor light emitting device with an active layer of the multiple quantum well structure, in which the device has an improved luminous intensity and a good electrostatic withstanding voltage, thereby allowing the expanded application to various products. The active layer 7 is formed of a multiple quantum well structure containing InaGa1-aN (0?a<1). The p-cladding layer 8 is formed on said active layer containing the p-type impurity. The p-cladding layer 8 is mode of a multi-film layer including a first nitride semiconductor film containing Al and a second nitride semiconductor film having a composition different from that of said first nitride semiconductor film. Alternatively, the p-cladding layer 8 is made of single-layered layer made of AlbGa1-bN (0?b?1). A low-doped layer 9 is grown on the p-cladding layer 8 having a p-type impurity concentration lower than that of the p-cladding layer 8.
    Type: Application
    Filed: October 18, 2004
    Publication date: July 7, 2005
    Inventor: Koji Tanizawa
  • Publication number: 20050035360
    Abstract: The present invention provides a nitride semiconductor light emitting device with an active layer of the multiple quantum well structure, in which the device has an improved luminous intensity and a good electrostatic withstanding voltage, thereby allowing the expanded application to various products. The active layer 7 is formed of a multiple quantum well structure containing InaGa1?aN (0?a<1). The p-cladding layer 8 is formed on said active layer containing the p-type impurity. The p-cladding layer 8 is mode of a multi-film layer including a first nitride semiconductor film containing Al and a second nitride semiconductor film having a composition different from that of said first nitride semiconductor film. Alternatively, the p-cladding layer 8 is made of single-layered layer made of AlbGa1?bN (0?b?1). A low-doped layer 9 is grown on the p-cladding layer 8 having a p-type impurity concentration lower than that of the p-cladding layer 8.
    Type: Application
    Filed: September 24, 2004
    Publication date: February 17, 2005
    Inventor: Koji Tanizawa
  • Patent number: 6838705
    Abstract: The present invention provides a nitride semiconductor light emitting device with an active layer of the multiple quantum well structure, in which the device has an improved luminous intensity and a good electrostatic withstanding voltage, thereby allowing the expanded application to various products. The active layer 7 is formed of a multiple quantum well structure containing InaGa1?aN (0?a<1). The p-cladding layer 8 is formed on said active layer containing the p-type impurity. The p-cladding layer 8 is made of a multi-film layer including a first nitride semiconductor film containing Al and a second nitride semiconductor film having a composition different from that of said first nitride semiconductor film. Alternatively, the p-cladding layer 8 is made of single-layered layer made of AlbGa1?bN (0?b?1). A low-doped layer 9 is grown on the p-cladding layer 8 having a p-type impurity concentration lower than that of the p-cladding layer 8.
    Type: Grant
    Filed: March 24, 2000
    Date of Patent: January 4, 2005
    Assignee: Nichia Corporation
    Inventor: Koji Tanizawa
  • Patent number: 6657234
    Abstract: An nitride semiconductor device for the improvement of lower operational voltage or increased emitting output, comprises an active layer comprising quantum well layer or layers and barrier layer or layers between n-type nitride. semiconductor layers and p-type nitride semiconductor layers, wherein said quantum layer in said active layer comprises InxGa1−xN (0<x<1) having a peak wavelength of 450 to 540 nm and said active layer comprises laminating layers of 9 to 13, in which at most 3 layers from the side of said n-type nitride semiconductor layers are doped with an n-type impurity selected from the group consisting of Si, Ge and Sn in a range of 5×1016 to 2×1018/cm3.
    Type: Grant
    Filed: March 16, 2001
    Date of Patent: December 2, 2003
    Assignee: Nichia Corporation
    Inventor: Koji Tanizawa
  • Publication number: 20030205711
    Abstract: An N-type nitride semiconductor laminate includes a substrate, a buffer layer made of AlaGa1-aN (0.05≦a≦0.8) which is formed on a surface of the substrate, and an n-side nitride semiconductor layer which is formed on the buffer layer.
    Type: Application
    Filed: January 2, 2003
    Publication date: November 6, 2003
    Inventors: Koji Tanizawa, Yasunobu Hosokawa
  • 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
  • Patent number: RE42008
    Abstract: An nitride semiconductor device for the improvement of lower operational voltage or increased emitting output, comprises an active layer comprising quantum well layer or layers and barrier layer or layers between n-type nitride, semiconductor layers and p-type nitride semiconductor layers, wherein said quantum layer in said active layer comprises InxGa1—xN (0<x<1) having a peak wavelength of 450 to 540 nm and said active layer comprises laminating layers of 9 to 13, in which at most 3 layers from the side of said n-type nitride semiconductor layers are doped with an n-type impurity selected from the group consisting of Si, Ge and Sn in a range of 5×1016 to 2×1018/cm3.
    Type: Grant
    Filed: June 7, 2000
    Date of Patent: December 28, 2010
    Assignee: Nichia Corporation
    Inventor: Koji Tanizawa
  • Patent number: RE45672
    Abstract: An nitride semiconductor device for the improvement of lower operational voltage or increased emitting output, comprises an active layer comprising quantum well layer or layers and barrier layer or layers between n-type nitride. semiconductor layers and p-type nitride semiconductor layers, wherein said quantum layer in said active layer comprises InxGa1?xN (0<x<1) having a peak wavelength of 450 to 540 nm and said active layer comprises laminating layers of 9 to 13, in which at most 3 layers from the side of said n-type nitride semiconductor layers are doped with an n-type impurity selected from the group consisting of Si, Ge and Sn in a range of 5×1016 to 2×1018/cm3.
    Type: Grant
    Filed: August 6, 2010
    Date of Patent: September 22, 2015
    Assignee: Nichia Corporation
    Inventor: Koji Tanizawa
  • Patent number: RE46444
    Abstract: An nitride semiconductor device for the improvement of lower operational voltage or increased emitting output, comprises an active layer comprising quantum well layer or layers and barrier layer or layers between n-type nitride. semiconductor layers and p-type nitride semiconductor layers, wherein said quantum layer in said active layer comprises InxGa1?xN (0<x<1) having a peak wavelength of 450 to 540 nm and said active layer comprises laminating layers of 9 to 13, in which at most 3 layers from the side of said n-type nitride semiconductor layers are doped with an n-type impurity selected from the group consisting of Si, Ge and Sn in a range of 5×1016 to 2×1018/cm3.
    Type: Grant
    Filed: July 1, 2015
    Date of Patent: June 20, 2017
    Assignee: NICHIA CORPORATION
    Inventor: Koji Tanizawa