Patents by Inventor Shozo Shikama

Shozo Shikama 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: 11125803
    Abstract: The present application relates to a technique of reducing the occurrence of a spot breakdown near a probe needle with the intention of preventing damage on the probe needle during a test implemented by applying a high voltage to a semiconductor device. In a method of measuring a semiconductor device, the semiconductor device includes: a semiconductor substrate (1), an epitaxial layer (2), at least one second conductivity type region (3) of a second conductivity type formed in a part of the surface layer of the epitaxial layer to have a contour, a Schottky electrode (11), an anode electrode (12), and a cathode electrode (13). A voltage is applied while the probe needle (21) is brought into contact with the upper surface of the anode electrode in a range in which the contour of the at least one second conductivity type region is formed in a plan view.
    Type: Grant
    Filed: September 1, 2016
    Date of Patent: September 21, 2021
    Assignee: Mitsubishi Electric Corporation
    Inventors: Koji Okuno, Shozo Shikama, Yoichiro Tarui
  • Publication number: 20190310306
    Abstract: The present application relates to a technique of reducing the occurrence of a spot breakdown near a probe needle with the intention of preventing damage on the probe needle during a test implemented by applying a high voltage to a semiconductor device. In a method of measuring a semiconductor device, the semiconductor device includes: a semiconductor substrate (1), an epitaxial layer (2), at least one second conductivity type region (3) of a second conductivity type formed in a part of the surface layer of the epitaxial layer to have a contour, a Schottky electrode (11), an anode electrode (12), and a cathode electrode (13). A voltage is applied while the probe needle (21) is brought into contact with the upper surface of the anode electrode in a range in which the contour of the at least one second conductivity type region is formed in a plan view.
    Type: Application
    Filed: September 1, 2016
    Publication date: October 10, 2019
    Applicant: Mitsubishi Electric Corporation
    Inventors: Koji OKUNO, Shozo SHIKAMA, Yoichiro TARUI
  • Patent number: 9188872
    Abstract: A method for manufacturing a semiconductor device includes a photolithography process having steps of a developing solution immersing process. The steps of the developing solution immersing process includes step (a) of dropping a developing solution on a silicon carbide semiconductor substrate and forming a developing solution film so as to have a film thickness of more than 6 ?m and step (b) of reducing the film thickness of the developing solution film to 6 ?m or less.
    Type: Grant
    Filed: April 1, 2014
    Date of Patent: November 17, 2015
    Assignee: Mitsubishi Electric Corporation
    Inventors: Sunao Aya, Shozo Shikama, Hideaki Yuki
  • Patent number: 9063428
    Abstract: A method for manufacturing a semiconductor device of the present invention includes steps of (a) preparing a silicon carbide substrate including a photoresist film formed on a principal surface, (b) dropping a first developing solution onto the photoresist film, (c) rotating the silicon carbide substrate to drain the first developing solution dropped onto the photoresist film after a lapse of a first development time since the end of the step (b), (d) dropping a second developing solution onto the photoresist film after the step (c), and (e) rotating the silicon carbide substrate to drain the second developing solution dropped onto the photoresist film after a lapse of a second development time since the end of the step (d).
    Type: Grant
    Filed: April 2, 2014
    Date of Patent: June 23, 2015
    Assignee: Mitsubishi Electric Corporation
    Inventors: Hideaki Yuki, Sunao Aya, Shozo Shikama
  • Publication number: 20140377709
    Abstract: A method for manufacturing a semiconductor device of the present invention includes steps of (a) preparing a silicon carbide substrate including a photoresist film formed on a principal surface, (b) dropping a first developing solution onto the photoresist film, (c) rotating the silicon carbide substrate to drain the first developing solution dropped onto the photoresist film after a lapse of a first development time since the end of the step (b), (d) dropping a second developing solution onto the photoresist film after the step (c), and (e) rotating the silicon carbide substrate to drain the second developing solution dropped onto the photoresist film after a lapse of a second development time since the end of the step (d).
    Type: Application
    Filed: April 2, 2014
    Publication date: December 25, 2014
    Applicant: Mitsubishi Electric Corporation
    Inventors: Hideaki YUKI, Sunao AYA, Shozo SHIKAMA
  • Publication number: 20140370445
    Abstract: A method for manufacturing a semiconductor device includes a photolithography process having steps of a developing solution immersing process. The steps of the developing solution immersing process includes step (a) of dropping a developing solution on a silicon carbide semiconductor substrate and forming a developing solution film so as to have a film thickness of more than 6 ?m and step (b) of reducing the film thickness of the developing solution film to 6 ?m or less.
    Type: Application
    Filed: April 1, 2014
    Publication date: December 18, 2014
    Applicant: Mitsubishi Electric Corporation
    Inventors: Sunao AYA, Shozo SHIKAMA, Hideaki YUKI
  • Patent number: 8569123
    Abstract: An object is to provide a method for manufacturing a silicon carbide semiconductor device in which a time required for removing a sacrificial oxide film can be shortened and damage to a surface of the silicon carbide layer can be reduced. The method for manufacturing a silicon carbide semiconductor device includes: (a) performing ion implantation to a silicon carbide layer; (b) performing activation annealing to the ion-implanted silicon carbide layer 2; (c) removing a surface layer of the silicon carbide layer 2, to which the activation annealing has been performed, by dry etching; (d) forming a sacrificial oxide film on a surface layer of the silicon carbide layer, to which the dry etching has been performed, by performing sacrificial oxidation thereto; and (e) removing the sacrificial oxide film by wet etching.
    Type: Grant
    Filed: September 1, 2009
    Date of Patent: October 29, 2013
    Assignee: Mitsubishi Electric Corporation
    Inventors: Yoshinori Matsuno, Kenichi Ohtsuka, Naoki Yutani, Kenichi Kuroda, Hiroshi Watanabe, Shozo Shikama
  • Patent number: 8377811
    Abstract: An object of the invention is to provide a method for manufacturing a silicon carbide semiconductor device having constant characteristics with reduced variations in forward characteristics. The method for manufacturing the silicon carbide semiconductor device according to the invention includes the steps of: (a) preparing a silicon carbide substrate; (b) forming an epitaxial layer on a first main surface of the silicon carbide substrate; (c) forming a protective film on the epitaxial layer; (d) forming a first metal layer on a second main surface of the silicon carbide substrate; (e) applying heat treatment to the silicon carbide substrate at a predetermined temperature to form an ohmic junction between the first metal layer and the second main surface of the silicon carbide substrate; (f) removing the protective film; (g) forming a second metal layer on the epitaxial layer; and (h) applying heat treatment to the silicon carbide substrate at a temperature from 400° C. to 600° C.
    Type: Grant
    Filed: August 8, 2008
    Date of Patent: February 19, 2013
    Assignee: Mitsubishi Electric Corporation
    Inventors: Yoshinori Matsuno, Kenichi Ohtsuka, Kenichi Kuroda, Shozo Shikama, Naoki Yutani
  • Publication number: 20120028453
    Abstract: An object is to provide a method for manufacturing a silicon carbide semiconductor device in which a time required for removing a sacrificial oxide film can be shortened and damage to a surface of the silicon carbide layer can be reduced. The method for manufacturing a silicon carbide semiconductor device includes: (a) performing ion implantation to a silicon carbide layer; (b) performing activation annealing to the ion-implanted silicon carbide layer 2; (c) removing a surface layer of the silicon carbide layer 2, to which the activation annealing has been performed, by dry etching; (d) forming a sacrificial oxide film on a surface layer of the silicon carbide layer, to which the dry etching has been performed, by performing sacrificial oxidation thereto; and (e) removing the sacrificial oxide film by wet etching.
    Type: Application
    Filed: September 1, 2009
    Publication date: February 2, 2012
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Yoshinori Matsuno, Kenichi Ohtsuka, Naoki Yutani, Kenichi Kuroda, Hiroshi Watanabe, Shozo Shikama
  • Publication number: 20090098719
    Abstract: An object of the invention is to provide a method for manufacturing a silicon carbide semiconductor device having constant characteristics with reduced variations in forward characteristics. The method for manufacturing the silicon carbide semiconductor device according to the invention includes the steps of: (a) preparing a silicon carbide substrate; (b) forming an epitaxial layer on a first main surface of the silicon carbide substrate; (c) forming a protective film on the epitaxial layer; (d) forming a first metal layer on a second main surface of the silicon carbide substrate; (e) applying heat treatment to the silicon carbide substrate at a predetermined temperature to form an ohmic junction between the first metal layer and the second main surface of the silicon carbide substrate; (f) removing the protective film; (g) forming a second metal layer on the epitaxial layer; and (h) applying heat treatment to the silicon carbide substrate at a temperature from 400° C. to 600° C.
    Type: Application
    Filed: August 8, 2008
    Publication date: April 16, 2009
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Yoshinori MATSUNO, Kenichi Ohtsuka, Kenichi Kuroda, Shozo Shikama, Naoki Yutani