Patents Examined by Felisha Hiteshew
  • Patent number: 6299682
    Abstract: A method for producing a silicon ingot having a directional solidification structure comprising the steps of: placing a silicon raw material into a crucible of a melting device constructed by mounting a chill plate on an underfloor heater, mounting a crucible with a large cross-sectional area on the chill plate, providing an overhead heater over the crucible, and surrounding the circumference of the crucible with a heat insulator; heat-melting the silicon raw material by flowing an electric current through the underfloor heater and overhead heater; chilling the bottom of the crucible by halting the electric current through the underfloor heater after the silicon raw material has been completely melted to form a molten silicon; chilling the bottom of the crucible by flowing an inert gas through the chill plate; and intermittently or continuously lowering the temperature of the overhead heater by intermittently or continuously decreasing the electric current through the overhead heater, and an apparatus for pro
    Type: Grant
    Filed: September 8, 2000
    Date of Patent: October 9, 2001
    Assignee: Mitsubishi Materials Corporation
    Inventors: Saburo Wakita, Akira Mitsuhashi, Yoshinobu Nakada, Jun-ichi Sasaki, Yuhji Ishiwari