Patents by Inventor Naoki Fukunaga

Naoki Fukunaga 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: 6433374
    Abstract: A photodiode converts light incident thereon into an electric signal by a junction between an N-type epitaxial layer and a P-type epitaxial layer with a sufficiently small junction capacitance. The photodiode is surrounded by a P+-type buried isolating diffused layer and a P-type isolating diffused layer, and thus is electrically separated from a signal processing circuit including a MOS transistor.
    Type: Grant
    Filed: October 29, 2001
    Date of Patent: August 13, 2002
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Naoki Fukunaga, Kazuhiro Natsuaki
  • Patent number: 6404029
    Abstract: A photosensitive device includes a semiconductor substrate and a first semiconductor layer, both of a first conductivity type, with the semiconductor layer being formed on the semiconductor substrate and having a lower impurity concentration than that of the semiconductor substrate. A second semiconductor layer, of a second conductivity type, is formed on the first semiconductor layer and at least one diffusion layer of the first conductivity type is formed from the surface of the second semiconductor layer so as to reach the surface of the first semiconductor layer. The diffusion layer subdivides the second semiconductor layer into a plurality of semiconductor regions At least one photodiode portion for converting signal light into an electrical signal is formed at a junction between at least one of the plurality of semiconductor regions and the first semiconductor layer.
    Type: Grant
    Filed: September 6, 2000
    Date of Patent: June 11, 2002
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Makoto Hosokawa, Naoki Fukunaga, Takahiro Takimoto, Masaru Kubo, Toshihiko Fukushima, Isamu Ohkubo
  • Publication number: 20020050593
    Abstract: A photodiode converts light incident thereon into an electric signal by a junction between an N-type epitaxial layer and a P-type epitaxial layer with a sufficiently small junction capacitance. The photodiode is surrounded by a P+-type buried isolating diffused layer and a P-type isolating diffused layer, and thus is electrically separated from a signal processing circuit including a MOS transistor.
    Type: Application
    Filed: October 29, 2001
    Publication date: May 2, 2002
    Inventors: Naoki Fukunaga, Kazuhiro Natsuaki
  • Publication number: 20020044580
    Abstract: A corrosion-resistant conductive layer (TiW layer) formed of a corrosion-resistant material is formed to extend from a bonding pad portion to an interconnection portion of a light receiving element. A semiconductor laser device according to the present invention includes the light receiving element.
    Type: Application
    Filed: January 11, 2001
    Publication date: April 18, 2002
    Inventors: Isamu Ohkubo, Kazuhiro Natsuaki, Naoki Fukunaga, Masaru Kubo
  • Publication number: 20020038868
    Abstract: A photodiode includes a first conductivity type semiconductor substrate or a first conductivity type semiconductor layer; a second conductivity type semiconductor layer provided on the first conductivity type semiconductor substrate or the first conductivity type semiconductor layer; an anti-reflection film provided on a surface of a portion of the second conductivity type semiconductor layer which is in a light receiving area; a first conductive layer provided in an area in the vicinity of the light receiving area; and a passivation layer provided on the first conductive layer. Light incident on the photodiode is detected by a junction of the one of the first conductivity type semiconductor substrate and the first conductivity type semiconductor layer, and the second conductivity type semiconductor layer. The area in the vicinity of the light receiving area includes a window area having an opening in the passivation layer for partially exposing the first conductive layer.
    Type: Application
    Filed: October 30, 2001
    Publication date: April 4, 2002
    Inventors: Hideo Wada, Isamu Ohkubo, Kazuhiro Natsuaki, Naoki Fukunaga, Shigeki Hayashida
  • Patent number: 6313484
    Abstract: A circuit-integrated light-receiving device of the present invention includes: a semiconductor substrate of a first conductivity type; a first semiconductor crystal growth layer of the first conductivity type provided on a surface of the semiconductor substrate, wherein the first semiconductor crystal growth layer includes a first portion whose impurity concentration gradually decreases in a direction away from the surface of the semiconductor substrate and a second portion located in a first region above the first portion whose impurity concentration distribution is uniform in a depth direction; a buried diffusion layer of the first conductivity type located in a second region which is above the first portion of the first semiconductor crystal growth layer and does not overlap the first region; a second semiconductor crystal growth layer of a second conductivity type which is provided across a surface of the first semiconductor crystal growth layer and a surface of the buried diffusion layer; and a separatio
    Type: Grant
    Filed: December 28, 1999
    Date of Patent: November 6, 2001
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Isamu Ohkubo, Masaru Kubo, Naoki Fukunaga, Takahiro Takimoto, Mutsumi Oka, Toshimitsu Kasamatsu
  • Patent number: 6114740
    Abstract: The circuit-integrating light-receiving element of this invention includes: a semiconductor substrate of a first conductivity type; a first semiconductor layer of a second conductivity type formed over the semiconductor substrate; a first semiconductor layer of the first conductivity type for dividing the first semiconductor layer into semiconductor regions of the second conductivity type; light-detecting sections being constituted by the divided semiconductor regions and underlying regions of the semiconductor substrate, a divided photodiode being composed of the light-detecting sections; a second semiconductor layer of the second conductivity type formed only in the vicinity of the first semiconductor layer of the first conductivity type functioning as a division section of the divided photodiode and within the regions of the semiconductor substrate forming the respective light-detecting sections; and a second semiconductor layer of the first conductivity type formed in a surface region of the first semicon
    Type: Grant
    Filed: September 30, 1997
    Date of Patent: September 5, 2000
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Takahiro Takimoto, Naoki Fukunaga, Masaru Kubo
  • Patent number: 6049117
    Abstract: A light-receiving element includes a semiconductor substrate of a first conductivity type; a first semiconductor layer of a second conductivity type which is formed in a predetermined region on a surface of the semiconductor substrate of the first conductivity type; and at least one semiconductor region of the first conductivity type which is formed so as to extend from an upper surface of the first semiconductor layer of the second conductivity type to the surface of the semiconductor substrate of the first conductivity type, thereby dividing the first semiconductor layer of the second conductivity type into a plurality of semiconductor regions of the second conductivity type. In the light-receiving element, a specific resistance of the semiconductor substrate of the first conductivity type is set in a predetermined range such that a condition Xd.gtoreq.
    Type: Grant
    Filed: September 20, 1996
    Date of Patent: April 11, 2000
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Naoki Fukunaga, Masaru Kubo
  • Patent number: 6005278
    Abstract: A divided photodiode includes a semiconductor substrate; a semiconductor layer formed on a surface of the semiconductor substrate; and a plurality of isolating diffusion regions formed in a plurality of regions in the semiconductor layer so as to respectively extend from a surface of the semiconductor layer opposite to the other surface thereof in contact with a surface of the semiconductor substrate and to reach regions under the surface of the semiconductor substrate, thereby dividing the semiconductor layer into at least three semiconductor regions. A first buried diffusion region is further formed under the other isolating diffusion regions except for a particular one located in an isolating section in a combination of a plurality of the semiconductor regions which are adjacent to each other via the isolating section, and a depletion of the semiconductor substrate in a region under the other isolating diffusion region by the application of a reverse bias thereto is suppressed.
    Type: Grant
    Filed: January 23, 1998
    Date of Patent: December 21, 1999
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Naoki Fukunaga, Takahiro Takimoto, Masaru Kubo
  • Patent number: 5602415
    Abstract: A light receiving device including a semiconductor substrate of a first conductivity type; a first semiconductor layer of a second conductivity type which is formed on the semiconductor substrate of the first conductivity type; and a semiconductor layer of the first conductivity type which elongates from a surface of the first semiconductor substrate of the second conductivity type to reach a surface of the semiconductor substrate of the first conductivity type, the semiconductor layer splitting the first semiconductor layer of the second conductivity type into a plurality of semiconductor regions of the second conductivity type. The portion of the semiconductor layer of the first conductivity type which overlaps with the semiconductor substrate of the first conductivity type is formed as a semiconductor region of the first conductivity type and has a high-impurity density.
    Type: Grant
    Filed: June 2, 1995
    Date of Patent: February 11, 1997
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Masaru Kubo, Naoki Fukunaga, Motohiko Yamamoto