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).

  • Patent number: 10907272
    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: Grant
    Filed: December 17, 2018
    Date of Patent: February 2, 2021
    Assignee: SHOWA DENKO K.K.
    Inventor: Yohei Fujikawa
  • Publication number: 20200407872
    Abstract: Provided is a single crystal growth crucible including a first housing and a second housing, in which a fitting portion between the first housing and the second housing has a first protruding portion, which is provided by protruding inner wall side of the first housing toward the second housing, and a second protruding portion, which is provided by protruding outer wall side of the second housing toward the first housing and covers an outer circumferential surface of the first protruding portion, the first protruding portion is formed such that an outer diameter of a tip portion thereof is larger than that of a base portion thereof in the protruding direction, and the second protruding portion is formed such that an inner diameter of a tip portion thereof is smaller than that of a base portion thereof in the protruding direction, the outer diameter of the tip portion of the first protruding portion is equal to or smaller than the inner diameter of the tip portion of the second protruding portion at room tempe
    Type: Application
    Filed: June 24, 2020
    Publication date: December 31, 2020
    Applicant: SHOWA DENKO K.K.
    Inventor: Yohei FUJIKAWA
  • Patent number: 10844517
    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: Grant
    Filed: December 19, 2018
    Date of Patent: November 24, 2020
    Assignee: SHOWA DENKO K.K.
    Inventor: Yohei Fujikawa
  • Patent number: 10837123
    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: Grant
    Filed: December 19, 2018
    Date of Patent: November 17, 2020
    Assignee: SHOWA DENKO K.K.
    Inventor: Yohei Fujikawa
  • Publication number: 20200224328
    Abstract: According to the invention, a SiC single crystal growth crucible includes: a raw material accommodation portion which accommodates a SiC raw material; and a seed crystal support portion which supports a seed crystal disposed on an upper portion of the raw material accommodation portion, in which the raw material accommodation portion has a tapered portion, an inner surface of which is tapered off downward.
    Type: Application
    Filed: January 6, 2020
    Publication date: July 16, 2020
    Applicant: SHOWA DENKO K.K.
    Inventor: Yohei FUJIKAWA
  • Publication number: 20200190691
    Abstract: A SiC single crystal manufacturing apparatus of the present invention includes a growth container having a growth space in which a SiC single crystal is grown in a first direction and a heat insulating material which covers the growth container and includes a plurality of units, and the plurality of units include a first unit and a second unit having at least a thermal conductivity different from that of the first unit, and the first unit includes a container made of at least one of graphite and a metal carbide and a filler filled into the container in a replaceable manner.
    Type: Application
    Filed: December 12, 2019
    Publication date: June 18, 2020
    Applicant: SHOWA DENKO K.K.
    Inventor: Yohei FUJIKAWA
  • Publication number: 20200165743
    Abstract: In a method of producing a SiC single crystal ingot of the present invention, in a lower part of a crucible, a high thermal conductivity raw material layer containing a high thermal conductivity raw material and a low thermal conductivity raw material layer containing a low thermal conductivity raw material in at least one of a position above or below the high thermal conductivity raw material layer are disposed to form a raw material part, and heating is performed so that the raw material part reaches the maximum temperature in the high thermal conductivity raw material layer and a SiC single crystal ingot is grown.
    Type: Application
    Filed: November 25, 2019
    Publication date: May 28, 2020
    Applicant: SHOWA DENKO K.K.
    Inventor: Yohei FUJIKAWA
  • Publication number: 20200149190
    Abstract: A SiC single crystal manufacturing apparatus of the present invention is a SiC single crystal manufacturing apparatus that manufactures a SiC single crystal by performing crystal growth on a growth surface of a seed crystal disposed inside a crucible, and the crucible 1 is able to accommodate a raw material M for a SiC single crystal therein, and includes a crucible lower portion 1A and a crucible upper portion 1B, the crucible lower portion including a bottom portion 1Aa and a side portion 1Ab, and the crucible upper portion including a top portion 1Ba provided with a seed crystal installation portion 1Bc for installing a seed crystal SD and a side portion 1Bb.
    Type: Application
    Filed: November 12, 2019
    Publication date: May 14, 2020
    Applicant: SHOWA DENKO K.K.
    Inventor: Yohei FUJIKAWA
  • Publication number: 20200087815
    Abstract: A manufacturing method of a SiC ingot includes a crystal growth step of growing a crystal on a principal plane having an offset angle with respect to a {0001} plane, in which, at least in a latter half growth step of the crystal growth step, after the crystal in the crystal growth step grows 7 mm or more from the principal plane, and in which, the crystal is grown by setting an acute angle, between the {0001} plane and an inclined plane which is perpendicular to a cut section cut along an offset direction and passes through both a center of a crystal growth surface and an offset downstream end portion of the crystal growth surface, to be equal to or more than an angle smaller than an offset angle by 2° and equal to or less than 8.6°.
    Type: Application
    Filed: December 22, 2017
    Publication date: March 19, 2020
    Applicant: SHOWA DENKO K.K.
    Inventors: Yohei FUJIKAWA, Hideyuki UEHIGASHI
  • Publication number: 20200080229
    Abstract: The present invention provides a single crystal growth method capable of suppressing the recrystallization of the raw material gas subjected to sublimation on the surface of the raw material, and suppressing the generation of different polytypes in the crystal growing single crystal. The single crystal growth method is carried out in a crucible comprising an inner bottom for providing a raw material and a crystal mounting part facing the inner bottom. The method comprises in the following order: providing the raw material in the inner bottom; covering at least a part of a surface of the raw material with a metal carbide powder in a plan view from the crystal mounting part; and growing a single crystal disposed in the crystal mounting part by sublimating the raw material by heating.
    Type: Application
    Filed: September 4, 2019
    Publication date: March 12, 2020
    Applicant: SHOWA DENKO K.K.
    Inventor: Yohei Fujikawa
  • Publication number: 20200080952
    Abstract: A thermal conductivity measuring device includes a sample container that has a plurality of storage sections; a drive unit that is configured to move the plurality of storage sections of the sample container; and a radiation thermometer that is configured to measure the temperature of a predetermined position of the sample container.
    Type: Application
    Filed: September 4, 2019
    Publication date: March 12, 2020
    Applicant: SHOWA DENKO K.K.
    Inventor: Yohei FUJIKAWA
  • Publication number: 20200080233
    Abstract: The present invention provides a single crystal growth crucible and a single crystal growth method which can suppress the recrystallization of the raw material gas which has been sublimated on the surface of the raw material and can suppress the generation of different polytypes in single crystal growth. The single crystal growth crucible includes an inner bottom, a crystal mounting part, and a deposition preventing member, wherein a raw material is provided in the inner bottom, the crystal mounting part faces the inner bottom, the deposition preventing member has a first surface comprising metal carbide, a first surface is disposed to face the crystal mounting part, the deposition preventing member is disposed in a central area of the inner bottom in a plan view from the crystal mounting part, and the first surface is disposed in accordance with the position of the surface of the raw material.
    Type: Application
    Filed: September 4, 2019
    Publication date: March 12, 2020
    Applicant: SHOWA DENKO K.K.
    Inventor: Yohei FUJIKAWA
  • Publication number: 20200048793
    Abstract: This shielding member that is placed between a SiC source loading portion and a crystal installation portion in an apparatus for single crystal growth, wherein the device includes a crystal growth container including the SiC source loading portion which accommodates a SiC source in an inner bottom portion, and the crystal installation portion facing the SiC source loading portion, and a heating unit that is configured to heat the crystal growth container, and the device grows a single crystal of the SiC source on a crystal installed on the crystal installation portion by sublimating the SiC source from the SiC source loading portion; the shielding member includes a plurality of shielding plates, wherein each area of the plurality of shielding plates is 40% or less of a base area of the crystal growth container, and wherein, in a case where the SiC source loading portion is filled with a SiC source, a shielding ratio provided by a projection surface of the plurality of shielding plates, which is projected on a
    Type: Application
    Filed: August 6, 2019
    Publication date: February 13, 2020
    Applicant: SHOWA DENKO K.K.
    Inventor: Yohei FUJIKAWA
  • Publication number: 20200020777
    Abstract: In a SiC wafer, a difference between a threading dislocation density of threading dislocations exposed on a first surface and a threading dislocation density of threading dislocations exposed on a second surface is 10% or less of the threading dislocation density of the surface with a higher threading dislocation density among the first surface and the second surface, and 90% or more of the threading dislocations exposed on the surface with a higher threading dislocation density among the first surface and the second surface extend to the surface with a lower threading dislocation density.
    Type: Application
    Filed: December 22, 2017
    Publication date: January 16, 2020
    Applicants: SHOWA DENKO K.K., DENSO CORPORATION
    Inventors: Yohei FUJIKAWA, Hidetaka TAKABA
  • Publication number: 20190360118
    Abstract: A SiC single crystal composite includes: a central portion positioned at a center in plan view; and an outer circumferential portion surrounding an outer circumference of the central portion, in which crystal planes of the central portion and the outer circumferential portion are inclined to each other or different from each other, a boundary is present between the central portion and the outer circumferential portion, and a direction of a crystal constituting the central portion and a direction of a crystal constituting the outer circumferential portion are different from each other via the boundary.
    Type: Application
    Filed: November 14, 2017
    Publication date: November 28, 2019
    Applicants: SHOWA DENKO K.K., DENSO CORPORATION
    Inventors: Yohei FUJIKAWA, Hideyuki UEHIGASHI
  • Publication number: 20190345631
    Abstract: A shielding member, wherein the shielding member is formed of at least one of structure which has a non-flat plate shape having an inclined surface, and the inclined surface is located on a side of a substrate support part when the shielding member is disposed in a single crystal growth device, wherein the single crystal growth device comprising: a crystal growth container; a source storage part that is positioned at a lower inner part of the crystal growth container; the substrate support part, wherein the support part is disposed above the source storage part and supports a substrate to make the substrate face the source storage part; and a heating device that is disposed on an outer circumference of the crystal growth container, wherein the shielding member is disposed between the source storage part and the substrate support part, and wherein a single crystal of a source is grown on the substrate by sublimating the source from the source storage part.
    Type: Application
    Filed: May 8, 2019
    Publication date: November 14, 2019
    Applicant: SHOWA DENKO K.K.
    Inventor: Yohei FUJIKAWA
  • Publication number: 20190338444
    Abstract: A shielding member includes a plurality of shielding plates, in which the plurality of shielding plates are arranged without gaps therebetween in a plan view from a crystal installation part, and the shielding member is disposed between a source material accommodation part and the crystal installation part, in an apparatus for growing single crystals, wherein the apparatus includes a container for crystal growth that has the source material accommodation part at an inner bottom part, and has the crystal installation part that faces the source material accommodation part, and includes a heating part that is configured to heat the container for crystal growth, in which a single crystal of the source material is grown on a crystal installed in the crystal installation part by subliming the source material from the source material accommodation part.
    Type: Application
    Filed: April 23, 2019
    Publication date: November 7, 2019
    Applicant: SHOWA DENKO K.K.
    Inventors: Yoshiteru HOSAKA, Yohei FUJIKAWA
  • Publication number: 20190330765
    Abstract: The present invention provides a heat-insulating shield member, wherein the heat-insulating shield member is arranged and used between a SiC source housing (3) and a substrate support (4) in a single crystal manufacturing apparatus (10), wherein the single crystal manufacturing apparatus (10) comprises a crystal growth container (2) and a heating member (5) arranged on an outer periphery of the crystal growth container (2), wherein the crystal growth container (2) includes the SiC source housing (3) disposed at a lower portion of the apparatus, and the substrate support (4) which is arranged above the SiC source housing (3) and supports a substrate (S) used for crystal growth so as to face the SiC source housing (3), and wherein the single crystal manufacturing apparatus (10) is configured to grow a single crystal (W) from a SiC source (M) on the substrate (S) by sublimating the SiC source (M) from the SiC source housing (3).
    Type: Application
    Filed: April 19, 2019
    Publication date: October 31, 2019
    Applicant: SHOWA DENKO K.K.
    Inventor: Yohei FUJIKAWA
  • 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