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).
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Patent number: 11125803Abstract: 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: GrantFiled: September 1, 2016Date of Patent: September 21, 2021Assignee: Mitsubishi Electric CorporationInventors: Koji Okuno, Shozo Shikama, Yoichiro Tarui
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Publication number: 20190310306Abstract: 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: ApplicationFiled: September 1, 2016Publication date: October 10, 2019Applicant: Mitsubishi Electric CorporationInventors: Koji OKUNO, Shozo SHIKAMA, Yoichiro TARUI
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Patent number: 9188872Abstract: 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: GrantFiled: April 1, 2014Date of Patent: November 17, 2015Assignee: Mitsubishi Electric CorporationInventors: Sunao Aya, Shozo Shikama, Hideaki Yuki
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Patent number: 9063428Abstract: 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: GrantFiled: April 2, 2014Date of Patent: June 23, 2015Assignee: Mitsubishi Electric CorporationInventors: Hideaki Yuki, Sunao Aya, Shozo Shikama
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Publication number: 20140377709Abstract: 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: ApplicationFiled: April 2, 2014Publication date: December 25, 2014Applicant: Mitsubishi Electric CorporationInventors: Hideaki YUKI, Sunao AYA, Shozo SHIKAMA
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Publication number: 20140370445Abstract: 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: ApplicationFiled: April 1, 2014Publication date: December 18, 2014Applicant: Mitsubishi Electric CorporationInventors: Sunao AYA, Shozo SHIKAMA, Hideaki YUKI
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Patent number: 8569123Abstract: 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: GrantFiled: September 1, 2009Date of Patent: October 29, 2013Assignee: Mitsubishi Electric CorporationInventors: Yoshinori Matsuno, Kenichi Ohtsuka, Naoki Yutani, Kenichi Kuroda, Hiroshi Watanabe, Shozo Shikama
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Patent number: 8377811Abstract: 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: GrantFiled: August 8, 2008Date of Patent: February 19, 2013Assignee: Mitsubishi Electric CorporationInventors: Yoshinori Matsuno, Kenichi Ohtsuka, Kenichi Kuroda, Shozo Shikama, Naoki Yutani
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Publication number: 20120028453Abstract: 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: ApplicationFiled: September 1, 2009Publication date: February 2, 2012Applicant: MITSUBISHI ELECTRIC CORPORATIONInventors: Yoshinori Matsuno, Kenichi Ohtsuka, Naoki Yutani, Kenichi Kuroda, Hiroshi Watanabe, Shozo Shikama
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Publication number: 20090098719Abstract: 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: ApplicationFiled: August 8, 2008Publication date: April 16, 2009Applicant: MITSUBISHI ELECTRIC CORPORATIONInventors: Yoshinori MATSUNO, Kenichi Ohtsuka, Kenichi Kuroda, Shozo Shikama, Naoki Yutani