Patents by Inventor Takuya Kokawa

Takuya Kokawa 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).

  • Publication number: 20100213577
    Abstract: A semiconductor electronic device comprises a substrate; a buffer layer that comprises composite laminations of which a first semiconductor layer, that is formed of a compound semiconductor of a nitride system, that has a lattice constant to be as smaller than that of such the substrate, and that has a coefficient of thermal expansion to be as larger than that of such the substrate, and a second semiconductor layer that is formed of a compound semiconductor of a nitride system are formed as alternately on to such the substrate; a semiconductor operation layer that is formed of a compound semiconductor of a nitride system and that is formed on to such the buffer layer; and a dislocation reduction layer, which comprises a lower layer region and an upper layer region that are formed at any location at an inner side of such the buffer layer and that comprise an interface of a concave and convex shape therebetween, at which a threading dislocation that draws from such the lower layer region toward such the upper l
    Type: Application
    Filed: February 25, 2010
    Publication date: August 26, 2010
    Applicant: FURUKAWA ELECTRIC CO., LTD.
    Inventors: Sadahiro Kato, Yoshihiro Sato, Masayuki Iwami, Takuya Kokawa
  • Publication number: 20100078678
    Abstract: A semiconductor electronic device comprises a substrate; a buffer layer formed on said substrate, having two or more layers of composite layers in which a first semiconductor layer comprising nitride based compound semiconductor having smaller lattice constant and greater coefficient of thermal expansion than the substrate and a second semiconductor layer comprising nitride based compound semiconductor having smaller lattice constant and greater coefficient of thermal expansion than the first semiconductor layer are alternately laminated; a semiconductor operating layer comprising nitride based compound semiconductor formed on said buffer layer; a dislocation reducing layer comprising nitride based compound semiconductor, formed in a location between a location directly under said buffer layer and inner area of said semiconductor operating layer, and comprising a lower layer area and an upper layer area each having an uneven boundary surface, wherein threading dislocation extending from the lower layer area t
    Type: Application
    Filed: September 29, 2009
    Publication date: April 1, 2010
    Applicant: FURUKAWA ELECTRIC CO., LTD.
    Inventors: Takuya Kokawa, Sadahiro Kato, Yoshihiro Sato, Masayuki Iwami
  • Publication number: 20090200645
    Abstract: A semiconductor electronic device comprises a substrate; a buffer layer formed on the substrate, the buffer layer including not less than two layers of composite layer in which a first semiconductor layer formed of a nitride-based compound semiconductor layer having a lattice constant smaller than a lattice constant of the substrate and a thermal expansion coefficient larger than a thermal expansion coefficient of the substrate and a second semiconductor layer formed of a nitride-based compound semiconductor having a lattice constant smaller than a lattice constant of the first semiconductor layer and a thermal expansion coefficient larger than a thermal expansion coefficient of the substrate are alternately laminated; an intermediate layer provided between the substrate and the buffer layer, the intermediate layer being formed of a nitride-based compound semiconductor having a lattice constant smaller than a lattice constant of the first semiconductor layer and a thermal expansion coefficient larger than a t
    Type: Application
    Filed: February 3, 2009
    Publication date: August 13, 2009
    Applicant: The Furukawa Electric Co., LTD.
    Inventors: Takuya Kokawa, Sadahiro Kato, Yoshihiro Sato, Masayuki Iwami