Patents by Inventor Tetsuya Ishidaira

Tetsuya Ishidaira 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 pulling a silicon single crystal by imposing a periodic rotation rate on a constant rotation rate
    Patent number: 5215620
    Abstract: This is a new method for pulling a silicon single crystal. When the silicon single crystal is pulled from a quartz crucible which is provided with a rotation rate more than zero, exclusive of zero rpm according to the Czochralski process, a reference rotation rate of the quartz crucible is controlled by a predetermined program. This method is characterized in that a pulse-like increase or decrease in a rotation rate is superimposed to the reference rotation rate and differences in and cycles of the rotation rate are set by the predetermined program.
    Type: Grant
    Filed: December 24, 1991
    Date of Patent: June 1, 1993
    Assignee: Shin-Etsu Handotai Co. Ltd.
    Inventors: Yoshihiro Kodama, Tetsuya Ishidaira, Koji Kanno, Shin-ichi Furuse