Patents by Inventor Akira Hirako

Akira Hirako 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).

  • Light emitting ceramic substrate including group-III nitride
    Patent number: 9373687
    Abstract: In a semiconductor device, a YAG substrate is formed as a single-crystal substrate of any of surface orientations (100), (110), and (111). In the fabrication of the semiconductor device, a TMAl gas is first fed onto the YAG substrate so as to form a nucleation layer made of aluminum, which is a group-III element. Then, an NH3 gas is fed onto the nucleation layer. This turns the surface of the nucleation layer into a group-V element and then forms a group-III-V compound layer of AlN. Then, a mixed gas of TMAl gas and NH3 gas is fed onto the group-III-V compound layer so as to form another group-III-V compound layer. Finally, a group-III nitride semiconductor layer is crystal-grown on the group-III compound layer.
    Type: Grant
    Filed: November 19, 2012
    Date of Patent: June 21, 2016
    Assignees: KOITO MANUFACTURING CO., LTD., TOKYO UNIVERSITY OF SCIENCE
    Inventors: Akihiro Nomura, Kazuhiro Ohkawa, Akira Hirako
  • SEMICONDUCTOR DEVICE, FABRICATION METHOD OF THE SEMICONDUCTOR DEVICES
    Publication number: 20110073995
    Abstract: In a semiconductor device, a YAG substrate is formed as a single-crystal substrate of any of surface orientations (100), (110), and (111). In the fabrication of the semiconductor device, a TMAl gas is first fed onto the YAG substrate so as to form a nucleation layer made of aluminum, which is a group-III element. Then, an NH3 gas is fed onto the nucleation layer. This turns the surface of the nucleation layer into a group-V element and then forms a group-III-V compound layer of AlN. Then, a mixed gas of TMAl gas and NH3 gas is fed onto the group-III-V compound layer so as to form another group-III-V compound layer. Finally, a group-III nitride semiconductor layer is crystal-grown on the group-III compound layer.
    Type: Application
    Filed: September 7, 2010
    Publication date: March 31, 2011
    Applicants: KOITO MANUFACTURING CO., LTD., TOKYO UNIVERSITY OF SCIENCE
    Inventors: Akihiro Nomura, Kazuhiro Ohkawa, Akira Hirako