Patents by Inventor Nobuhiro Kusaba

Nobuhiro Kusaba 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: 20080053370
    Abstract: An aspect of the invention provides a silicon single crystal production method in which a dislocation-free feature can easily be achieved to enhance crystal quality irrespective of a crystal orientation. In the silicon single crystal production method of the invention, by a Czochralski method, in dipping the seed crystal in the melt, a melt temperature is set to an optimum temperature at which the seed crystal is brought into contact with a melt surface, the melt temperature is lowered, the seed crystal is pulled up while a pulling rate of the seed crystal is increased, and the pulling rate is kept at a constant rate to form the neck portion at the time that a pulling diameter reaches a target neck diameter. The invention is suitable to the case in which a silicon single crystal having a crystal orientation <110> is pulled up using the seed crystal having the crystal orientation <110>.
    Type: Application
    Filed: September 4, 2007
    Publication date: March 6, 2008
    Inventors: Shuichi Inami, Kuniharu Inoue, Manabu Moroishi, Tsuguya Fukagawa, Nobuhiro Kusaba
  • Publication number: 20080053368
    Abstract: Exemplary embodiments of the invention provide a method for producing a low-resistivity silicon single crystal in which a silicon wafer having a crystal axis orientation [110] can be obtained and dislocations are sufficiently eliminated, and a method for producing a low-resistance silicon wafer having the crystal axis orientation [110] from the silicon single crystal obtained by the low-resistivity silicon single crystal production method. In the silicon single crystal production method of the invention which employs a Czochralski method, the silicon single crystal whose center axis is inclined by 0.6° to 100 relative to a-crystal axis [110] is grown by dipping a silicon seed crystal in a silicon melt. Boron as a dopant is added in the silicon melt so that a boron concentration ranges from 6.25×1017 to 2.5×1020 atoms/cm3, a center axis of the silicon seed crystal is inclined by 0.
    Type: Application
    Filed: September 4, 2007
    Publication date: March 6, 2008
    Inventors: Shuichi Inami, Kuniharu Inoue, Manabu Moroishi, Tsuguya Fukagawa, Nobuhiro Kusaba