Patents by Inventor Keigo Hoshikawa

Keigo Hoshikawa 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).

  • Method for manufacturing dislocation-free silicon single crystal
    Publication number: 20010020438
    Abstract: A method for manufacturing a dislocation-free silicon single crystal, includes the steps of preparing a silicon seed crystal formed of a dislocation-free single crystal having a boron concentration of 1×1018 atoms/cm3 or more, preparing a silicon melt having a boron concentration which differs from that of the seed crystal by 7×1018 atoms/cm3 or less, and bringing the seed crystal into contact with the silicon melt to grow the silicon single crystal.
    Type: Application
    Filed: January 23, 2001
    Publication date: September 13, 2001
    Applicant: President of Shinshu University
    Inventors: Keigo Hoshikawa, Xinming Huang, Tatsuo Fukami, Toshinori Taishi
  • Growth method for a rod form of single oxide crystal
    Patent number: 5458083
    Abstract: A method of growing a rod form of a single oxide crystal is disclosed. The method uses a slit die which is placed in a crucible with a starting melt. The melt is seeded with a seed crystal while being rotated. The resulting crystal will have the same sectional shape as the shape of the upper surface of the die.
    Type: Grant
    Filed: March 28, 1994
    Date of Patent: October 17, 1995
    Assignee: Chichibu Cement Co., Ltd.
    Inventors: Tsuguo Fukuda, Keigo Hoshikawa, Hiroshi Machida
  • Rutile single crystals and their growth processes
    Patent number: 5431124
    Abstract: A rutile single crystal with no grain boundaries of large inclination is obtained by an EFG crystal growth process wherein a die provided with slits is incorporated in a feed melt 2 to deliver up the melt through the slits until it reaches the upper face of the die, thereby obtaining a single crystal conforming in configuration to the die by pulling growth.
    Type: Grant
    Filed: January 18, 1994
    Date of Patent: July 11, 1995
    Assignee: Chichibu Cement Co., Ltd.
    Inventors: Hiroshi Machida, Tsuguo Fukuda, Keigo Hoshikawa
  • Process for pulling a single crystal
    Patent number: 4863554
    Abstract: An apparatus for pulling a single crystal by CZ method or LEC method is improved. To this end, the heater for heating the inside of the furnace is divided at least in the vicinity of the solid-liquid interface into at least two heaters. Using this apparatus, a single crystal with a decreased dislocation density can be obtained.
    Type: Grant
    Filed: February 20, 1987
    Date of Patent: September 5, 1989
    Assignees: Sumitomo Electric Industries, Ltd., Nippon Telegraph & Telephone Public Corporation
    Inventors: Akihisa Kawasaki, Toshihiro Kotani, Ryusuke Nakai, Shintaro Miyazawa, Keigo Hoshikawa