Patents by Inventor Tokuya Kozaki
Tokuya Kozaki 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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Patent number: 7015053Abstract: A nitride semiconductor laser device has an improved stability of the lateral mode under high output power and a longer lifetime, so that the device can be applied to write and read light sources for recording media with high capacity. The nitride semiconductor laser device includes an active layer, a p-side cladding layer, and a p-side contact layer laminated in turn. The device further includes a waveguide region of a stripe structure formed by etching from the p-side contact layer. The stripe width provided by etching is within the stripe range of 1 to 3 ?m and the etching depth is below the thickness of the p-side cladding layer of 0.1 ?m and above the active layer. Particularly, when a p-side optical waveguide layer includes a projection part of the stripe structure and a p-type nitride semiconductor layer on the projection part and the projection part of the p-side optical waveguide layer has a thickness of not more than 1 ?m, an aspect ratio is improved in far field image.Type: GrantFiled: November 4, 2003Date of Patent: March 21, 2006Assignee: Nichia CorporationInventors: Tokuya Kozaki, Masahiko Sano, Shuji Nakamura, Shinichi Nagahama
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Publication number: 20050202682Abstract: A method of growing a nitride semiconductor crystal which has very few crystal defects and can be used as a substrate is disclosed. This invention includes the step of forming a first selective growth mask on a support member including a dissimilar substrate having a major surface and made of a material different from a nitride semiconductor, the first selective growth mask having a plurality of first windows for selectively exposing the upper surface of the support member, and the step of growing nitride semiconductor portions from the upper surface, of the support member, which is exposed from the windows, by using a gaseous Group 3 element source and a gaseous nitrogen source, until the nitride semiconductor portions grown in the adjacent windows combine with each other on the upper surface of the selective growth mask.Type: ApplicationFiled: February 9, 2005Publication date: September 15, 2005Inventors: Hiroyuki Kiyoku, Shuji Nakamura, Tokuya Kozaki, Naruhito Iwasa, Kazuyuki Chocho
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Patent number: 6940103Abstract: A method of growing a nitride semiconductor crystal which has very few crystal defects and can be used as a substrate is disclosed. This invention includes the step of forming a first selective growth mask on a support member including a dissimilar substrate having a major surface and made of a material different from a nitride semiconductor, the first selective growth mask having a plurality of first windows for selectively exposing the upper surface of the support member, and the step of growing nitride semiconductor portions from the upper surface, of the support member, which is exposed from the windows, by using a gaseous Group 3 element source and a gaseous nitrogen source, until the nitride semiconductor portions grown in the adjacent windows combine with each other on the upper surface of the selective growth mask.Type: GrantFiled: June 23, 2003Date of Patent: September 6, 2005Assignee: Nichia Chemical Industries, Ltd.Inventors: Hiroyuki Kiyoku, Shuji Nakamura, Tokuya Kozaki, Naruhito Iwasa, Kazuyuki Chocho
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Publication number: 20050098789Abstract: A nitride semiconductor device includes an n-type semiconductor layer, p-type semiconductor layer and an active layer of a quantum well structure that is sandwiched between said p-type and n-type nitride semiconductor layer, wherein the active layer has a first barrier layer, a second barrier layer and a third barrier layer. The first barrier layer is nearest to the p-type nitride semiconductor layer among the first, second and third barrier layers. The second barrier layer is nearest to the n-type nitride semiconductor layer among the first, second and third barrier layers. The third barrier layer is between the first and second barrier layers, and includes an upper barrier layer that contacts with a p-side surface of the well layer and a lower barrier layer that contacts with an n-side surface of said well layer. The upper and lower barrier layers having different composition or impurity concentrations.Type: ApplicationFiled: November 2, 2004Publication date: May 12, 2005Applicant: Nichia CorporationInventor: Tokuya Kozaki
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Patent number: 6861729Abstract: A nitride semiconductor substrate including (a) a supporting substrate, (b) a first nitride semiconductor layer having a periodical T-shaped cross-section, having grown from periodically arranged stripe-like, grid-like or island-like portions on the supporting substrate, and (c) a second nitride semiconductor substrate covering said supporting substrate, having grown from the top and side surfaces of said first nitride semiconductor layer, wherein a cavity is formed under the second nitride semiconductor layer. A protective layer having a periodically arranged stripe-like, grid-like or island-like apertures is formed on the supporting substrate. The first nitride semiconductor layer is laterally grown from the exposed portion of the substrate. The growth is stopped before the first nitride semiconductor layer covers the supporting substrate. Thus, the first nitride semiconductor layer has a periodical T-shaped cross-section.Type: GrantFiled: March 18, 2003Date of Patent: March 1, 2005Assignee: Nichia CorporationInventors: Tokuya Kozaki, Hiroyuki Kiyoku, Kazuyuki Chocho, Hitoshi Maegawa
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Publication number: 20050030994Abstract: The nitride semiconductor laser device has a counter electrode structure where contact resistance is reduced and manufacturing methods thereof are provided. The nitride semiconductor laser device comprises a nitride semiconductor substrate having a first main surface and a second main surface. A nitride semiconductor layer is stacked on the first main surface of the nitride semiconductor substrate. A ridge-shaped stripe is formed in the nitride semiconductor layer, and a resonance surface forms an optical waveguide in the direction perpendicular to the length of the ridge-shaped stripe. A first region having a crystal growth facet in the (0001) plane and a second region on the first main surface or the second main surface are provided. Further, a recess is formed in the second region of the first main surface and/or the second main surface. A ridge-shape stripe is formed over the first main surface of the nitride semiconductor substrate.Type: ApplicationFiled: July 12, 2004Publication date: February 10, 2005Inventors: Tokuya Kozaki, Keiji Sakamoto, Hiroaki Matsumura
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Patent number: 6838693Abstract: In the nitride semiconductor device of the present invention, an active layer 12 is sandwiched between a p-type nitride semiconductor layer 11 and an n-type nitride semiconductor layer 13. The active layer 12 has, at least, a barrier layer 2a having an n-type impurity; a well layer 1a made of a nitride semiconductor that includes In; and a barrier layer 2c that has a p-type impurity, or that has been grown without being doped. An appropriate injection of carriers into the active layer 12 becomes possible by arranging the barrier layer 2c nearest to the p-type layer side.Type: GrantFiled: May 22, 2003Date of Patent: January 4, 2005Assignee: Nichia CorporationInventor: Tokuya Kozaki
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Patent number: 6756611Abstract: A method of growing a nitride semiconductor crystal which has very few crystal defects and can be used as a substrate is disclosed. This invention includes the step of forming a first selective growth mask on a support member including a dissimilar substrate having a major surface and made of a material different from a nitride semiconductor, the first selective growth mask having a plurality of first windows for selectively exposing the upper surface of the support member, and the step of growing nitride semiconductor portions from the upper surface, of the support member, which is exposed from the windows, by using a gaseous Group 3 element source and a gaseous nitrogen source, until the nitride semiconductor portions grown in the adjacent windows combine with each other on the upper surface of the selective growth mask.Type: GrantFiled: October 2, 2002Date of Patent: June 29, 2004Assignee: Nichia Chemical Industries, Ltd.Inventors: Hiroyuki Kiyoku, Shuji Nakamura, Tokuya Kozaki, Naruhito Iwasa, Kazuyuki Chocho
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Publication number: 20040101986Abstract: A nitride semiconductor laser device has an improved stability of the lateral mode under high output power and a longer lifetime, so that the device can be applied to write and read light sources for recording media with high capacity. The nitride semiconductor laser device includes an active layer, a p-side cladding layer, and a p-side contact layer laminated in turn. The device further includes a waveguide region of a stripe structure formed by etching from the p-side contact layer. The stripe width provided by etching is within the stripe range of 1 to 3 &mgr;m and the etching depth is below the thickness of the p-side cladding layer of 0.1 &mgr;m and above the active layer. Particularly, when a p-side optical waveguide layer includes a projection part of the stripe structure and a p-type nitride semiconductor layer on the projection part and the projection part of the p-side optical waveguide layer has a thickness of not more than 1 &mgr;m, an aspect ratio is improved in far field image.Type: ApplicationFiled: November 4, 2003Publication date: May 27, 2004Applicant: Nichia CorporationInventors: Tokuya Kozaki, Masahiko Sano, Shuji Nakamura, Shinichi Nagahama
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Publication number: 20040094773Abstract: A method of growing a nitride semiconductor crystal which has very few crystal defects and can be used as a substrate is disclosed. This invention includes the step of forming a first selective growth mask on a support member including a dissimilar substrate having a major surface and made of a material different from a nitride semiconductor, the first selective growth mask having a plurality of first windows for selectively exposing the upper surface of the support member, and the step of growing nitride semiconductor portions from the upper surface, of the support member, which is exposed from the windows, by using a gaseous Group 3 element source and a gaseous nitrogen source, until the nitride semiconductor portions grown in the adjacent windows combine with each other on the upper surface of the selective growth mask.Type: ApplicationFiled: June 23, 2003Publication date: May 20, 2004Applicant: NICHIA CHEMICAL INDUSTRIES, LTD.Inventors: Hiroyuki Kiyoku, Shuji Nakamura, Tokuya Kozaki, Naruhito Iwasa, Kazuyuki Chocho
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Patent number: 6711191Abstract: A nitride semiconductor laser device has an improved stability of the lateral mode under high output power and a longer lifetime, so that the device can be applied to write and read light sources for recording media with high capacity. The nitride semiconductor laser device includes an active layer, a p-side cladding layer, and a p-side contact layer laminated in turn. The device further includes a waveguide region of a stripe structure formed by etching from the p-side contact layer. The stripe width provided by etching is within the stripe range of 1 to 3 &mgr;m and the etching depth is below the thickness of the p-side cladding layer of 0.1 &mgr;m and above the active layer. Particularly, when a p-side optical waveguide layer includes a projection part of the stripe structure and a p-type nitride semiconductor layer on the projection part and the projection part of the p-side optical waveguide layer has a thickness of not more than 1 &mgr;m, an aspect ratio is improved in far field image.Type: GrantFiled: March 3, 2000Date of Patent: March 23, 2004Assignee: Nichia CorporationInventors: Tokuya Kozaki, Masahiko Sano, Shuji Nakamura, Shinichi Nagahama
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Publication number: 20030205736Abstract: In the nitride semiconductor device of the present invention, an active layer 12 is sandwiched between a p-type nitride semiconductor layer 11 and an n-type nitride semiconductor layer 13. The active layer 12 has, at least, a barrier layer 2a having an n-type impurity; a well layer 1a made of a nitride semiconductor that includes In; and a barrier layer 2c that has a p-type impurity, or that has been grown without being doped. An appropriate injection of carriers into the active layer 12 becomes possible by arranging the barrier layer 2c nearest to the p-type layer side.Type: ApplicationFiled: May 22, 2003Publication date: November 6, 2003Applicant: Nichia Corporation.Inventor: Tokuya Kozaki
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Patent number: 6627520Abstract: A nitride semiconductor substrate including (a) a supporting substrate, (b) a first nitride semiconductor layer having a periodical T-shaped cross-section, having grown from periodically arranged stripe-like, grid-like or island-like portions on the supporting substrate, and (c) a second nitride semiconductor substrate covering said supporting substrate, having grown from the top and side surfaces of said first nitride semiconductor layer, wherein a cavity is formed under the second nitride semiconductor layer. A protective layer having a periodically arranged stripe-like, grid-like or island-like apertures is formed on the supporting substrate. The first nitride semiconductor layer is laterally grown from the exposed portion of the substrate. The growth is stopped before the first nitride semiconductor layer covers the supporting substrate. Thus, the first nitride semiconductor layer has a periodical T-shaped cross-section.Type: GrantFiled: October 1, 2002Date of Patent: September 30, 2003Assignee: Nichia CorporationInventors: Tokuya Kozaki, Hiroyuki Kiyoku, Kazuyuki Chocho, Hitoshi Maegawa
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Patent number: 6627974Abstract: A nitride semiconductor substrate including (a) a supporting substrate, (b) a first nitride semiconductor layer having a periodical T-shaped cross-section, having grown from periodically arranged stripe-like, grid-like or island-like portions on the supporting substrate, and (c) a second nitride semiconductor substrate covering said supporting substrate, having grown from the top and side surfaces of said first nitride semiconductor layer, wherein a cavity is formed under the second nitride semiconductor layer. A protective layer having a periodically arranged stripe-like, grid-like or island-like apertures is formed on the supporting substrate. The first nitride semiconductor layer is laterally grown from the exposed portion of the substrate. The growth is stopped before the first nitride semiconductor layer covers the supporting substrate. Thus, the first nitride semiconductor layer has a periodical T-shaped cross-section.Type: GrantFiled: June 15, 2001Date of Patent: September 30, 2003Assignee: Nichia CorporationInventors: Tokuya Kozaki, Hiroyuki Kiyoku, Kazuyuki Chocho, Hitoshi Maegawa
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Publication number: 20030160232Abstract: A nitride semiconductor substrate including (a) a supporting substrate, (b) a first nitride semiconductor layer having a periodical T-shaped cross-section, having grown from periodically arranged stripe-like, grid-like or island-like portions on the supporting substrate, and (c) a second nitride semiconductor substrate covering said supporting substrate, having grown from the top and side surfaces of said first nitride semiconductor layer, wherein a cavity is formed under the second nitride semiconductor layer.Type: ApplicationFiled: March 18, 2003Publication date: August 28, 2003Applicant: Nichia CorporationInventors: Tokuya Kozaki, Hiroyuki Kiyoku, Kazuyuki Chocho, Hitoshi Maegawa
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Patent number: 6586762Abstract: In the nitride semiconductor device of the present invention, an active layer 12 is sandwiched between a n-type nitride semiconductor layer 11 and an p-type nitride semiconductor layer 13. The active layer 12 has, at least, a barrier layer 2a having an n-type impurity; a well layer 1a made of a nitride semiconductor that includes In; and a barrier layer 2c that has a p-type impurity, or that has been grown without being doped. An appropriate injection of carriers into the active layer 12 becomes possible by arranging the barrier layer 2c nearest to the p-type layer side.Type: GrantFiled: July 5, 2001Date of Patent: July 1, 2003Assignee: Nichia CorporationInventor: Tokuya Kozaki
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Publication number: 20030037722Abstract: A method of growing a nitride semiconductor crystal which has very few crystal defects and can be used as a substrate is disclosed. This invention includes the step of forming a first selective growth mask on a support member including a dissimilar substrate having a major surface and made of a material different from a nitride semiconductor, the first selective growth mask having a plurality of first windows for selectively exposing the upper surface of the support member, and the step of growing nitride semiconductor portions from the upper surface, of the support member, which is exposed from the windows, by using a gaseous Group 3 element source and a gaseous nitrogen source, until the nitride semiconductor portions grown in the adjacent windows combine with each other on the upper surface of the selective growth mask.Type: ApplicationFiled: October 2, 2002Publication date: February 27, 2003Applicant: NICHIA CHEMICAL INDUSTRIES, LTD.Inventors: Hiroyuki Kiyoku, Shuji Nakamura, Tokuya Kozaki, Naruhito Iwasa, Kazuyuki Chocho
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Publication number: 20030032288Abstract: A nitride semiconductor substrate including (a) a supporting substrate, (b) a first nitride semiconductor layer having a periodical T-shaped cross-section, having grown from periodically arranged stripe-like, grid-like or island-like portions on the supporting substrate, and (c) a second nitride semiconductor substrate covering said supporting substrate, having grown from the top and side surfaces of said first nitride semiconductor layer, wherein a cavity is formed under the second nitride semiconductor layer.Type: ApplicationFiled: October 1, 2002Publication date: February 13, 2003Applicant: Nichia CorporationInventors: Tokuya Kozaki, Hiroyuki Kiyoku, Kazuyuki Chocho, Hitoshi Maegawa
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Publication number: 20020053676Abstract: In the nitride semiconductor device of the present invention, an active layer 12 is sandwiched between a p-type nitride semiconductor layer 11 and an n-type nitride semiconductor layer 13. The active layer 12 has, at least, a barrier layer 2a having an n-type impurity; a well layer 1a made of a nitride semiconductor that includes in; and a barrier layer 2c that has a p-type impurity, or that has been grown without being doped. An appropriate injection of carriers into the active layer 12 becomes possible by arranging the barrier layer 2c nearest to the p-type layer side.Type: ApplicationFiled: July 5, 2001Publication date: May 9, 2002Inventor: Tokuya Kozaki
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Publication number: 20020046693Abstract: A method of growing a nitride semiconductor crystal which has very few crystal defects and can be used as a substrate is disclosed. This invention includes the step of forming a first selective growth mask on a support member including a dissimilar substrate having a major surface and made of a material different from a nitride semiconductor, the first selective growth mask having a plurality of first windows for selectively exposing the upper surface of the support member, and the step of growing nitride semiconductor portions from the upper surface, of the support member, which is exposed from the windows, by using a gaseous Group 3 element source and a gaseous nitrogen source, until the nitride semiconductor portions grown in the adjacent windows combine with each other on the upper surface of the selective growth mask.Type: ApplicationFiled: November 8, 2001Publication date: April 25, 2002Applicant: NICHIA CHEMICAL INDUSTRIES, LTD.Inventors: Hiroyuki Kiyoku, Shuji Nakamura, Tokuya Kozaki, Naruhito Iwasa, Kazuyuki Chocho