Patents by Inventor Yutaka Mikawa

Yutaka Mikawa 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: 20120237431
    Abstract: To provide a production method for a nitride crystal, where a nitride crystal can be prevented from precipitating in a portion other than on a seed crystal and the production efficiency of a gallium nitride single crystal grown on the seed crystal can be enhanced. In a method for producing a nitride crystal by an ammonothermal method in a vessel containing a mineralizer-containing solution, out of the surfaces of said vessel and a member provided in said vessel, at least a part of the portion coming into contact with said solution is constituted by a metal or alloy containing one or more atoms selected from the group consisting of tantalum (Ta), tungsten (W) and titanium (Ti), and has a surface roughness (Ra) of less than 1.80 ?m.
    Type: Application
    Filed: May 29, 2012
    Publication date: September 20, 2012
    Applicants: MITSUBISHI CHEMICAL CORPORATION, THE JAPAN STEEL WORKS, LTD., TOHOKU UNIVERSITY
    Inventors: YUTAKA MIKAWA, MAKIKO KIYOMI, YUJI KAGAMITANI, TORU ISHIGURO, YOSHIHIKO YAMAMURA
  • Publication number: 20120164057
    Abstract: A semiconductor crystal is produced through crystal growth in the presence of a solvent in a supercritical and/or subcritical state in a reactor, wherein at least a part of the surface of the reactor and the surface of the member to be used inside the reactor is coated with a platinum group-Group 13 metal alloy coating film.
    Type: Application
    Filed: December 27, 2011
    Publication date: June 28, 2012
    Applicant: MITSUBISHI CHEMICAL CORPORATION
    Inventors: Hideo FUJISAWA, Yutaka Mikawa
  • Publication number: 20120112320
    Abstract: A production process for a nitride semiconductor crystal, comprising growing a semiconductor layer on a seed substrate to obtain a nitride semiconductor crystal, wherein the seed substrate comprises a plurality of seed substrates made of the same material, at least one of the plurality of seed substrates differs in the off-angle from the other seed substrates, and a single semiconductor layer is grown by disposing the plurality of seed substrates in a semiconductor crystal production apparatus, such that when the single semiconductor layer is grown on the plurality of seed substrates, the off-angle distribution in the single semiconductor layer becomes smaller than the off-angle distribution in the plurality of seed substrates.
    Type: Application
    Filed: December 1, 2011
    Publication date: May 10, 2012
    Applicant: MITSUBISHI CHEMICAL CORPORATION
    Inventors: Shuichi KUBO, Kenji Shimoyama, Kazumasa Kiyomi, Kenji Fujito, Yutaka Mikawa
  • Publication number: 20110268645
    Abstract: To grow a highly pure nitride crystal having a low oxygen concentration efficiently by an ammonothermal method. A process for producing a nitride crystal, which comprises bringing a reactant gas reactive with ammonia to form a mineralizer, and ammonia into contact with each other to prepare a mineralizer in a reactor or in a closed circuit connected to a reactor; and growing a nitride crystal by an ammonothermal method in the presence of the ammonia and the mineralizer.
    Type: Application
    Filed: January 7, 2010
    Publication date: November 3, 2011
    Applicants: TOHOKU UNIVERSITY, MITSUBISHI CHEMICAL CORPORATION
    Inventors: Yutaka Mikawa, Makiko Kiyomi, Yuji Kagamitani, Toru Ishiguro
  • Publication number: 20110117349
    Abstract: To produce a zinc oxide single crystal having a sufficiently low lithium concentration and a high crystallinity. A zinc oxide crystal is grown by hydrothermal synthesis method using a solution having a lithium concentration of 1 ppm or less (weight basis), while suppressing a fluctuation range of crystal growth temperature within 5° C. or at a temperature within the range of 300 to 370° C.
    Type: Application
    Filed: March 24, 2009
    Publication date: May 19, 2011
    Applicants: Fukuda Crystal Laboratory, Tokyo Denpa Co., Ltd., Mitsubishi Chemical Corporation
    Inventors: Yutaka Mikawa, Keiji Fukutomi, Takao Suzuki, Hirohisa Itoh