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).
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Publication number: 20140077157Abstract: 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: ApplicationFiled: November 22, 2013Publication date: March 20, 2014Applicant: Nichia CorporationInventors: Shuji NAKAMURA, Takashi Mukai, Koji Tanizawa, Tomotsugu Mitani, Hiromitsu Marui
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Patent number: 8592841Abstract: 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: GrantFiled: February 1, 2008Date of Patent: November 26, 2013Assignee: Nichia CorporationInventors: Shuji Nakamura, Takashi Mukai, Koji Tanizawa, Tomotsugu Mitani, Hiroshi Marui
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Patent number: 8076694Abstract: 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: GrantFiled: April 28, 2006Date of Patent: December 13, 2011Assignee: Nichia CorporationInventors: Yukio Narukawa, Tomotsugu Mitani, Masatsugu Ichikawa, Akira Kitano, Takao Misaki
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Patent number: 7947994Abstract: 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: GrantFiled: March 12, 2008Date of Patent: May 24, 2011Assignee: Nichia CorporationInventors: Koji Tanizawa, Tomotsugu Mitani, Yoshinori Nakagawa, Hironori Takagi, Hiromitsu Marui, Yoshikatsu Fukuda, Takeshi Ikegami
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Publication number: 20080191195Abstract: 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: ApplicationFiled: March 12, 2008Publication date: August 14, 2008Applicant: NICHIA CORPORATIONInventors: Koji TANIZAWA, Tomotsugu MITANI, Yoshinori NAKAGAWA, Hironori TAKAGI, Hiromitsu MARUI, Yoshikatsu FUKUDA, Takeshi IKEGAMI
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Patent number: 7402838Abstract: 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: GrantFiled: November 16, 2006Date of Patent: July 22, 2008Assignee: Nichia CorporationInventors: Koji Tanizawa, Tomotsugu Mitani, Yoshinori Nakagawa, Hironori Takagi, Hiromitsu Marui, Yoshikatsu Fukuda, Takeshi Ikegami
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Publication number: 20080149955Abstract: 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: ApplicationFiled: February 1, 2008Publication date: June 26, 2008Applicant: Nichia CorporationInventors: Shuji Nakamura, Takashi Mukai, Koji Tanizawa, Tomotsugu Mitani, Hiroshi Marui
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Patent number: 7365369Abstract: 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: GrantFiled: July 27, 1998Date of Patent: April 29, 2008Assignee: Nichia CorporationInventors: Shuji Nakamura, Takashi Mukai, Koji Tanizawa, Tomotsugu Mitani, Hiroshi Marui
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Publication number: 20070063207Abstract: 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: ApplicationFiled: November 16, 2006Publication date: March 22, 2007Inventors: Koji Tanizawa, Tomotsugu Mitani, Yoshinori Nakagawa, Hironori Takagi, Hiromitsu Marui, Yoshikatsu Fukuda, Takeshi Ikegami
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Patent number: 7193246Abstract: 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: GrantFiled: March 10, 1999Date of Patent: March 20, 2007Assignee: Nichia CorporationInventors: Koji Tanizawa, Tomotsugu Mitani, Yoshinori Nakagawa, Hironori Takagi, Hiromitsu Marui, Yoshikatsu Fukuda, Takeshi Ikegami
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Publication number: 20060243988Abstract: 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: ApplicationFiled: April 28, 2006Publication date: November 2, 2006Inventors: Yukio Narukawa, Tomotsugu Mitani, Masatsugu Ichikawa, Akira Kitano, Takao Misaki
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Publication number: 20030010993Abstract: 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: ApplicationFiled: May 1, 2000Publication date: January 16, 2003Inventors: SHUJI NAKAMURA, TAKASHI MUKAI, KOJI TANIZAWA, TOMOTSUGU MITANI, HIROSHI MARUI
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Patent number: 6337493Abstract: 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: GrantFiled: April 20, 2000Date of Patent: January 8, 2002Assignee: Nichia CorporationInventors: Koji Tanizawa, Hiroki Narimatsu, Tomoaki Sakai, Tomotsugu Mitani