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).
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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: 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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Patent number: 7348602Abstract: 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: GrantFiled: October 18, 2004Date of Patent: March 25, 2008Assignee: Nichia CorporationInventor: Koji Tanizawa
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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: 20050145860Abstract: 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: ApplicationFiled: October 18, 2004Publication date: July 7, 2005Inventor: Koji Tanizawa
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Publication number: 20050035360Abstract: 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: ApplicationFiled: September 24, 2004Publication date: February 17, 2005Inventor: Koji Tanizawa
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Patent number: 6838705Abstract: 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: GrantFiled: March 24, 2000Date of Patent: January 4, 2005Assignee: Nichia CorporationInventor: Koji Tanizawa
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Patent number: 6657234Abstract: 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: GrantFiled: March 16, 2001Date of Patent: December 2, 2003Assignee: Nichia CorporationInventor: Koji Tanizawa
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Publication number: 20030205711Abstract: 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: ApplicationFiled: January 2, 2003Publication date: November 6, 2003Inventors: Koji Tanizawa, Yasunobu Hosokawa
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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
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Patent number: RE42008Abstract: 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: GrantFiled: June 7, 2000Date of Patent: December 28, 2010Assignee: Nichia CorporationInventor: Koji Tanizawa
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Patent number: RE45672Abstract: 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: GrantFiled: August 6, 2010Date of Patent: September 22, 2015Assignee: Nichia CorporationInventor: Koji Tanizawa
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Patent number: RE46444Abstract: 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: GrantFiled: July 1, 2015Date of Patent: June 20, 2017Assignee: NICHIA CORPORATIONInventor: Koji Tanizawa