Patents by Inventor Yohei Fujikawa

Yohei Fujikawa 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: 20190330764
    Abstract: The present invention provides a crucible and a SiC single crystal growth apparatus capable of improving the efficiency of using source materials. The crucible includes a lid and a container. The container includes a bottom facing the lid. The bottom includes a recess which is recessed towards the lid.
    Type: Application
    Filed: April 23, 2019
    Publication date: October 31, 2019
    Applicant: SHOWA DENKO K.K.
    Inventor: Yohei Fujikawa
  • Publication number: 20190301051
    Abstract: A silicon carbide single crystal is grown by a method comprising: a single crystal growth step of growing a silicon carbide single crystal so as to not close a gap between a side surface of the silicon carbide single crystal growing on a silicon carbide seed crystal, and an inner-side surface of a guide member and a crystal deposited on the inner-side surface of the guide member; a crystal growth termination step of terminating crystal growth by temperature lowering; and a gap enlargement step, performed between the single crystal growth step and the crystal growth termination step, of enlarging the gap by maintaining a difference, Pin?Pout, between partial pressure Pin of Si2C in a source gas in the vicinity of an inlet of the gap and partial pressure Pout of Si2C in a source gas in the vicinity of an outlet of the gap at 0.18 torr or less.
    Type: Application
    Filed: December 15, 2017
    Publication date: October 3, 2019
    Applicant: SHOWA DENKO K.K.
    Inventors: Yohei FUJIKAWA, Hidetaka TAKABA
  • Publication number: 20190194822
    Abstract: A SiC ingot includes a core portion; and a surface layer that is formed on a plane of the core portion in a growing direction, and a coefficient of linear thermal expansion of the surface layer is smaller than a coefficient of linear thermal expansion of the core portion.
    Type: Application
    Filed: December 18, 2018
    Publication date: June 27, 2019
    Applicant: SHOWA DENKO K.K.
    Inventors: Rimpei KINDAICHI, Yohei Fujikawa, Yoshishige Okuno
  • Publication number: 20190194823
    Abstract: A method of measuring a SiC ingot includes a measuring step of measuring a curving direction of an atomic arrangement plane of a SiC single crystal at least along a first direction passing through a center in plan view and a second direction intersecting with the first direction to obtain a shape of the atomic arrangement plane; and a crystal growth step of performing crystal growth using the SiC single crystal as a seed crystal, in which in a case where the shape of the atomic arrangement plane measured in the measuring step is a saddle type, a crystal growth condition in the crystal growth step is set such that a convexity of a second growth front at the end of crystal growth becomes larger than a convexity of a first growth front when an amount of crystal growth in the center of the seed crystal is 7 mm.
    Type: Application
    Filed: December 19, 2018
    Publication date: June 27, 2019
    Applicant: SHOWA DENKO K.K.
    Inventor: Yohei FUJIKAWA
  • Publication number: 20190194824
    Abstract: A method of processing a SiC single crystal includes a measuring step of measuring a shape of an atomic arrangement plane of the SiC single crystal along at least a first direction passing through a center in plan view and a second direction orthogonal to the first direction; and a surface processing step of processing a first plane serving as an attachment plane of the SiC single crystal, in which the surface processing step includes a grinding step of grinding the first plane, and in the grinding step, a difference is given to a surface state between the first plane and a second plane facing the first plane, and the atomic arrangement plane is flattened by Twyman's effect.
    Type: Application
    Filed: December 19, 2018
    Publication date: June 27, 2019
    Applicant: SHOWA DENKO K.K.
    Inventor: Yohei FUJIKAWA
  • Publication number: 20190194819
    Abstract: The present invention provides a method including: a temperature raising step of raising a temperature in a crystal growing furnace with a silicon carbide raw material and a silicon carbide seed crystal arranged therein to a crystal growing temperature; a single crystal growing step of maintaining the crystal growing temperature and causing a silicon carbide single crystal to grow on the silicon carbide seed crystal; and a temperature lowering step of lowering the temperature in the crystal growing furnace from the crystal growing temperature to stop growth of the silicon carbide single crystal, in which the method further comprises, between the single crystal growing step and the temperature lowering step, a temperature lowering preparation step of maintaining the temperature in the crystal growing furnace at the crystal growing temperature and causing concentration of nitrogen gas in the crystal growing furnace to increase to be higher than concentration of nitrogen gas in the temperature raising step and i
    Type: Application
    Filed: December 17, 2018
    Publication date: June 27, 2019
    Applicant: SHOWA DENKO K.K.
    Inventor: Yohei Fujikawa