Patents by Inventor Shunta HARADA

Shunta HARADA 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: 11094835
    Abstract: It is an object of the present invention to provide a silicon carbide substrate having a low defect density that does not contaminate a process device and a silicon carbide semiconductor device including the silicon carbide substrate. A silicon carbide substrate according to the present invention is a silicon carbide substrate including: a substrate inner portion; and a substrate outer portion surrounding the substrate inner portion, wherein non-dopant metal impurity concentration of the substrate inner portion is 1×1016 cm?3 or more, and a region of the substrate outer portion at least on a surface side thereof is a substrate surface region in which the non-dopant metal impurity concentration is less than 1×1016 cm?3.
    Type: Grant
    Filed: February 20, 2018
    Date of Patent: August 17, 2021
    Assignees: MITSUBISHI ELECTRIC CORPORATION, NATIONAL UNIVERSITY CORPORATION NAGOYA UNIVERSITY
    Inventors: Tomoaki Furusho, Takanori Tanaka, Takeharu Kuroiwa, Toru Ujihara, Shunta Harada, Kenta Murayama
  • Publication number: 20200013907
    Abstract: It is an object of the present invention to provide a silicon carbide substrate having a low defect density that does not contaminate a process device and a silicon carbide semiconductor device including the silicon carbide substrate. A silicon carbide substrate according to the present invention is a silicon carbide substrate including: a substrate inner portion; and a substrate outer portion surrounding the substrate inner portion, wherein non-dopant metal impurity concentration of the substrate inner portion is 1×1016 cm?3 or more, and a region of the substrate outer portion at least on a surface side thereof is a substrate surface region in which the non-dopant metal impurity concentration is less than 1×1016 cm?3.
    Type: Application
    Filed: February 20, 2018
    Publication date: January 9, 2020
    Applicants: Mitsubishi Electric Corporation, NATIONAL UNIVERSITY CORPORATION NAGOYA UNIVERSITY
    Inventors: Tomoaki FURUSHO, Takanori TANAKA, Takeharu KUROIWA, Toru UJIHARA, Shunta HARADA, Kenta MURAYAMA
  • Patent number: 10151046
    Abstract: Provided is a method that allows growing a single crystal of silicon carbide on an off-substrate of silicon carbide while suppressing surface roughening. The method for producing a crystal of silicon carbide includes rotating a seed crystal of silicon carbide while bringing the seed crystal into contact with a starting material solution containing silicon and carbon. A crystal growth surface of the seed crystal has an off-angle, and the position of a rotation center of the seed crystal lies downstream of the central position of the seed crystal in a step flow direction that is a formation direction of the off-angle.
    Type: Grant
    Filed: September 10, 2015
    Date of Patent: December 11, 2018
    Assignees: National University Corporation Nagoya University, Central Glass Co., Ltd.
    Inventors: Toru Ujihara, Shunta Harada, Daiki Koike, Tomonori Umezaki
  • Publication number: 20170260647
    Abstract: Provided is a method that allows growing a single crystal of silicon carbide on an off-substrate of silicon carbide while suppressing surface roughening. The method for producing a crystal of silicon carbide includes rotating a seed crystal of silicon carbide while bringing the seed crystal into contact with a starting material solution containing silicon and carbon. A crystal growth surface of the seed crystal has an off-angle, and the position of a rotation center of the seed crystal lies downstream of the central position of the seed crystal in a step flow direction that is a formation direction of the off-angle.
    Type: Application
    Filed: September 10, 2015
    Publication date: September 14, 2017
    Inventors: Toru UJIHARA, Shunta HARADA, Daiki KOIKE, Tomonori UMEZAKI
  • Patent number: 9671356
    Abstract: A technique of measuring energy of electrons excited by exposing a semiconductor material to solar ray is proposed. A surface layer having a negative electron affinity is formed on the surface of a semiconductor material. The semiconductor material is placed in a vacuum environment and exposed to solar ray. Photoelectrons emitted from the surface layer having the negative electron affinity are guided to an energy analyzer, and the energy of electrons excited by the solar ray is measured. Since the surface layer having the negative electron affinity is used, the photoelectrons are obtained from the electrons excited by the solar ray, and thereby energy measurement becomes possible.
    Type: Grant
    Filed: December 24, 2013
    Date of Patent: June 6, 2017
    Assignee: NATIONAL UNIVERSITY CORPORATION NAGOYA UNIVERSITY
    Inventors: Toru Ujihara, Fumiaki Ichihashi, Daiki Shimura, Makoto Kuwahara, Shunta Harada
  • Publication number: 20160047760
    Abstract: A technique of measuring energy of electrons excited by exposing a semiconductor material to solar ray is proposed. A surface layer having a negative electron affinity is formed on the surface of a semiconductor material. The semiconductor material is placed in a vacuum environment and exposed to solar ray. Photoelectrons emitted from the surface layer having the negative electron affinity are guided to an energy analyzer, and the energy of electrons excited by the solar ray is measured. Since the surface layer having the negative electron affinity is used, the photoelectrons are obtained from the electrons excited by the solar ray, and thereby energy measurement becomes possible.
    Type: Application
    Filed: December 24, 2013
    Publication date: February 18, 2016
    Applicant: NATIONAL UNIVERSITY CORPORATION NAGOYA UNIVERSITY
    Inventors: Toru UJIHARA, Fumiaki ICHIHASHI, Daiki SHIMURA, Makoto KUWAHARA, Shunta HARADA
  • Publication number: 20150167197
    Abstract: Provided is a crystal producing apparatus capable of producing a single crystal having excellent quality. The crystal producing apparatus for growing a single crystal on a crystal growth surface of a seed crystal in a raw material solution by a liquid phase growth method, includes: a liquid tub which accommodates a raw material solution; a crystal holding element which holds a seed crystal; and a solution flowing element which allows the raw material solution in the liquid tub to flow. Among these, the crystal holding element is able to hold the seed crystal in the liquid tub and is movable in at least a partial region on an xy plane perpendicular to a z-axis that extends in a depth direction of the liquid tub.
    Type: Application
    Filed: February 24, 2015
    Publication date: June 18, 2015
    Inventors: Toru UJIHARA, Shunta HARADA, Kazuaki SEKI, Can ZHU, Mitsuya NAGAOKA