Patents by Inventor Takuma Mizobe

Takuma Mizobe 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: 11948794
    Abstract: Provided is a method of manufacturing a silicon carbide epitaxial wafer appropriate for suppressing an occurrence of a triangular defect. A method of manufacturing a silicon carbide epitaxial wafer includes: an etching process of etching a surface of a silicon carbide substrate at a first temperature using etching gas including H2; a process of flattening processing of flattening the surface etched in the etching process, at a second temperature using gas including H2 gas, first Si supply gas, and first C supply gas; and an epitaxial layer growth process of performing an epitaxial growth on the surface flattened in the process of flattening processing, at a third temperature using gas including second Si supply gas and second C supply gas, wherein the first temperature T1, the second temperature T2, and the third temperature T3 satisfy T1>T2>T3.
    Type: Grant
    Filed: April 27, 2021
    Date of Patent: April 2, 2024
    Assignee: Mitsubishi Electric Corporation
    Inventors: Masashi Sakai, Takuma Mizobe, Takuyo Nakamura
  • Publication number: 20220028688
    Abstract: Provided is a method of manufacturing a silicon carbide epitaxial wafer appropriate for suppressing an occurrence of a triangular defect. A method of manufacturing a silicon carbide epitaxial wafer includes: an etching process of etching a surface of a silicon carbide substrate at a first temperature using etching gas including H2; a process of flattening processing of flattening the surface etched in the etching process, at a second temperature using gas including H2 gas, first Si supply gas, and first C supply gas; and an epitaxial layer growth process of performing an epitaxial growth on the surface flattened in the process of flattening processing, at a third temperature using gas including second Si supply gas and second C supply gas, wherein the first temperature T1, the second temperature T2, and the third temperature T3 satisfy T1>T2>T3.
    Type: Application
    Filed: April 27, 2021
    Publication date: January 27, 2022
    Applicant: Mitsubishi Electric Corporation
    Inventors: Masashi SAKAI, Takuma MIZOBE, Takuyo NAKAMURA
  • Patent number: 10950435
    Abstract: A SiC substrate (1) has an off angle ?°. A SiC epitaxial layer (2) having a film thickness of Tm ?m is provided on the SiC substrate (1). Triangular defects (3) are formed on a surface of the SiC epitaxial layer (2). A density of triangular defects (3) having a length of Tm/Tan ?×0.9 or more in a substrate off direction is denoted by A. A density of triangular (3) defects having a length smaller than Tm/Tan ?×0.9 in the substrate off direction is denoted by B. B/A?0.5 is satisfied.
    Type: Grant
    Filed: April 6, 2017
    Date of Patent: March 16, 2021
    Assignee: Mitsubishi Electric Corporation
    Inventors: Kenichi Hamano, Akihito Ohno, Takuma Mizobe, Yasuhiro Kimura, Yoichiro Mitani
  • Patent number: 10910218
    Abstract: A SiC substrate (1) has an off angle ?°. A SiC epitaxial layer (2) having a film thickness of Tm ?m is provided on the SiC substrate (1). Triangular defects (3) are formed on a surface of the SiC epitaxial layer (2). A density of triangular defects (3) having a length of Tm/Tan ?×0.9 or more in a substrate off direction is denoted by A. A density of triangular (3) defects having a length smaller than Tm/Tan ?×0.9 in the substrate off direction is denoted by B. B/A?0.5 is satisfied.
    Type: Grant
    Filed: April 6, 2017
    Date of Patent: February 2, 2021
    Assignee: Mitsubishi Electric Corporation
    Inventors: Kenichi Hamano, Akihito Ohno, Takuma Mizobe, Yasuhiro Kimura, Yoichiro Mitani
  • Patent number: 10707075
    Abstract: A semiconductor wafer includes a silicon carbide substrate having a first carrier concentration, a carrier concentration transition layer, and an epitaxial layer provided on the carrier concentration transition layer, the epitaxial layer having a second carrier concentration, and the second carrier concentration being lower than the first carrier concentration. The carrier concentration transition layer has a concentration gradient in the thickness direction. The carrier concentration decreases as the film thickness increases from an interface between a layer directly below the carrier concentration transition layer and the carrier concentration transition layer, and the carrier concentration decreases at a lower rate of decrease as the film thickness of the carrier concentration transition layer increases.
    Type: Grant
    Filed: November 28, 2016
    Date of Patent: July 7, 2020
    Assignee: Mitsubishi Electric Corporation
    Inventors: Kenichi Hamano, Akihito Ohno, Takuma Mizobe, Masashi Sakai, Yasuhiro Kimura, Yoichiro Mitani, Takashi Kanazawa
  • Publication number: 20200144053
    Abstract: A semiconductor wafer includes a silicon carbide substrate having a first carrier concentration, a carrier concentration transition layer, and an epitaxial layer provided on the carrier concentration transition layer, the epitaxial layer having a second carrier concentration, and the second carrier concentration being lower than the first carrier concentration. The carrier concentration transition layer has a concentration gradient in the thickness direction. The carrier concentration decreases as the film thickness increases from an interface between a layer directly below the carrier concentration transition layer and the carrier concentration transition layer, and the carrier concentration decreases at a lower rate of decrease as the film thickness of the carrier concentration transition layer increases.
    Type: Application
    Filed: November 28, 2016
    Publication date: May 7, 2020
    Applicant: Mitsubishi Electric Corporation
    Inventors: Kenichi HAMANO, Akihito OHNO, Takuma MIZOBE, Masashi SAKAI, Yasuhiro KIMURA, Yoichiro MITANI, Takashi KANAZAWA
  • Publication number: 20200020528
    Abstract: A SiC substrate (1) has an off angle ?°. A SiC epitaxial layer (2) having a film thickness of Tm ?m is provided on the SiC substrate (1). Triangular defects (3) are formed on a surface of the SiC epitaxial layer (2). A density of triangular defects (3) having a length of Tm/Tan ?×0.9 or more in a substrate off direction is denoted by A. A density of triangular (3) defects having a length smaller than Tm/Tan ?×0.9 in the substrate off direction is denoted by B. B/A?0.5 is satisfied.
    Type: Application
    Filed: April 6, 2017
    Publication date: January 16, 2020
    Applicant: Mitsubishi Electric Corporation
    Inventors: Kenichi HAMANO, Akihito OHNO, Takuma MIZOBE, Yasuhiro KIMURA, Yoichiro MITANI
  • Publication number: 20170040166
    Abstract: A manufacturing method for manufacturing a silicon carbide epitaxial wafer includes: introducing a cleaning gas into a growth furnace to remove dendrite-like polycrystal of silicon carbide attached to an inner wall of the growth furnace; after introducing the cleaning gas, bringing a silicon carbide substrate in the growth furnace; and growing a silicon carbide epitaxial layer on the silicon carbide substrate by introducing a processing gas into the growth furnace to manufacture a silicon carbide epitaxial wafer, wherein the cleaning gas having fluid energy of 1.6E?4 [J] or higher is introduced into the growth furnace.
    Type: Application
    Filed: April 5, 2016
    Publication date: February 9, 2017
    Applicant: Mitsubishi Electric Corporation
    Inventors: Akihito OHNO, Masashi SAKAI, Yoichiro MITANI, Takahiro YAMAMOTO, Yasuhiro KIMURA, Takuma MIZOBE, Nobuyuki TOMITA
  • Patent number: 9564315
    Abstract: A manufacturing method for manufacturing a silicon carbide epitaxial wafer includes: introducing a cleaning gas into a growth furnace to remove dendrite-like polycrystal of silicon carbide attached to an inner wall of the growth furnace; after introducing the cleaning gas, bringing a silicon carbide substrate in the growth furnace; and growing a silicon carbide epitaxial layer on the silicon carbide substrate by introducing a processing gas into the growth furnace to manufacture a silicon carbide epitaxial wafer, wherein the cleaning gas having fluid energy of 1.6E-4 [J] or higher is introduced into the growth furnace.
    Type: Grant
    Filed: April 5, 2016
    Date of Patent: February 7, 2017
    Assignee: Mitsubishi Electric Corporation
    Inventors: Akihito Ohno, Masashi Sakai, Yoichiro Mitani, Takahiro Yamamoto, Yasuhiro Kimura, Takuma Mizobe, Nobuyuki Tomita