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).

  • Patent number: 7015053
    Abstract: 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: Grant
    Filed: November 4, 2003
    Date of Patent: March 21, 2006
    Assignee: Nichia Corporation
    Inventors: Tokuya Kozaki, Masahiko Sano, Shuji Nakamura, Shinichi Nagahama
  • Publication number: 20050202682
    Abstract: 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: Application
    Filed: February 9, 2005
    Publication date: September 15, 2005
    Inventors: Hiroyuki Kiyoku, Shuji Nakamura, Tokuya Kozaki, Naruhito Iwasa, Kazuyuki Chocho
  • Patent number: 6940103
    Abstract: 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: Grant
    Filed: June 23, 2003
    Date of Patent: September 6, 2005
    Assignee: Nichia Chemical Industries, Ltd.
    Inventors: Hiroyuki Kiyoku, Shuji Nakamura, Tokuya Kozaki, Naruhito Iwasa, Kazuyuki Chocho
  • Publication number: 20050098789
    Abstract: 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: Application
    Filed: November 2, 2004
    Publication date: May 12, 2005
    Applicant: Nichia Corporation
    Inventor: Tokuya Kozaki
  • Patent number: 6861729
    Abstract: 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: Grant
    Filed: March 18, 2003
    Date of Patent: March 1, 2005
    Assignee: Nichia Corporation
    Inventors: Tokuya Kozaki, Hiroyuki Kiyoku, Kazuyuki Chocho, Hitoshi Maegawa
  • Publication number: 20050030994
    Abstract: 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: Application
    Filed: July 12, 2004
    Publication date: February 10, 2005
    Inventors: Tokuya Kozaki, Keiji Sakamoto, Hiroaki Matsumura
  • Patent number: 6838693
    Abstract: 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: Grant
    Filed: May 22, 2003
    Date of Patent: January 4, 2005
    Assignee: Nichia Corporation
    Inventor: Tokuya Kozaki
  • Patent number: 6756611
    Abstract: 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: Grant
    Filed: October 2, 2002
    Date of Patent: June 29, 2004
    Assignee: Nichia Chemical Industries, Ltd.
    Inventors: Hiroyuki Kiyoku, Shuji Nakamura, Tokuya Kozaki, Naruhito Iwasa, Kazuyuki Chocho
  • Publication number: 20040101986
    Abstract: 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: Application
    Filed: November 4, 2003
    Publication date: May 27, 2004
    Applicant: Nichia Corporation
    Inventors: Tokuya Kozaki, Masahiko Sano, Shuji Nakamura, Shinichi Nagahama
  • Publication number: 20040094773
    Abstract: 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: Application
    Filed: June 23, 2003
    Publication date: May 20, 2004
    Applicant: NICHIA CHEMICAL INDUSTRIES, LTD.
    Inventors: Hiroyuki Kiyoku, Shuji Nakamura, Tokuya Kozaki, Naruhito Iwasa, Kazuyuki Chocho
  • Patent number: 6711191
    Abstract: 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: Grant
    Filed: March 3, 2000
    Date of Patent: March 23, 2004
    Assignee: Nichia Corporation
    Inventors: Tokuya Kozaki, Masahiko Sano, Shuji Nakamura, Shinichi Nagahama
  • Publication number: 20030205736
    Abstract: 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: Application
    Filed: May 22, 2003
    Publication date: November 6, 2003
    Applicant: Nichia Corporation.
    Inventor: Tokuya Kozaki
  • Patent number: 6627520
    Abstract: 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: Grant
    Filed: October 1, 2002
    Date of Patent: September 30, 2003
    Assignee: Nichia Corporation
    Inventors: Tokuya Kozaki, Hiroyuki Kiyoku, Kazuyuki Chocho, Hitoshi Maegawa
  • Patent number: 6627974
    Abstract: 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: Grant
    Filed: June 15, 2001
    Date of Patent: September 30, 2003
    Assignee: Nichia Corporation
    Inventors: Tokuya Kozaki, Hiroyuki Kiyoku, Kazuyuki Chocho, Hitoshi Maegawa
  • Publication number: 20030160232
    Abstract: 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: Application
    Filed: March 18, 2003
    Publication date: August 28, 2003
    Applicant: Nichia Corporation
    Inventors: Tokuya Kozaki, Hiroyuki Kiyoku, Kazuyuki Chocho, Hitoshi Maegawa
  • Patent number: 6586762
    Abstract: 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: Grant
    Filed: July 5, 2001
    Date of Patent: July 1, 2003
    Assignee: Nichia Corporation
    Inventor: Tokuya Kozaki
  • Publication number: 20030037722
    Abstract: 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: Application
    Filed: October 2, 2002
    Publication date: February 27, 2003
    Applicant: NICHIA CHEMICAL INDUSTRIES, LTD.
    Inventors: Hiroyuki Kiyoku, Shuji Nakamura, Tokuya Kozaki, Naruhito Iwasa, Kazuyuki Chocho
  • Publication number: 20030032288
    Abstract: 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: Application
    Filed: October 1, 2002
    Publication date: February 13, 2003
    Applicant: Nichia Corporation
    Inventors: Tokuya Kozaki, Hiroyuki Kiyoku, Kazuyuki Chocho, Hitoshi Maegawa
  • Publication number: 20020053676
    Abstract: 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: Application
    Filed: July 5, 2001
    Publication date: May 9, 2002
    Inventor: Tokuya Kozaki
  • Publication number: 20020046693
    Abstract: 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: Application
    Filed: November 8, 2001
    Publication date: April 25, 2002
    Applicant: NICHIA CHEMICAL INDUSTRIES, LTD.
    Inventors: Hiroyuki Kiyoku, Shuji Nakamura, Tokuya Kozaki, Naruhito Iwasa, Kazuyuki Chocho