Patents by Inventor Misako Honaga

Misako Honaga 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).

  • Publication number: 20120056202
    Abstract: A MOSFET, which is a semiconductor device allowing for reduced on-resistance while restraining stacking faults from being produced due to heat treatment in a device manufacturing process, includes: a silicon carbide substrate; an active layer made of single-crystal silicon carbide and disposed on one main surface of the silicon carbide substrate; a source contact electrode disposed on the active layer; and a drain electrode formed on the other main surface of the silicon carbide substrate. The silicon carbide substrate includes: a base layer made of silicon carbide; and a SiC layer made of single-crystal silicon carbide and disposed on the base layer. Further, the base layer has an impurity concentration greater than 2×1019 cm?3, and the SiC layer has an impurity concentration greater than 5×1018 cm?3 and smaller than 2×1019 cm?3.
    Type: Application
    Filed: April 27, 2010
    Publication date: March 8, 2012
    Applicant: Sumitomo Electric Industries, Ltd.
    Inventors: Keiji Wada, Shin Harada, Takeyoshi Masuda, Misako Honaga, Makoto Sasaki, Taro Nishiguchi, Yasuo Namikawa, Shinsuke Fujiwara
  • Publication number: 20120007104
    Abstract: A semiconductor device employing silicon carbide, and the like are provided. In the semiconductor device, even when an electrode material and an upper electrode material are different, a problem does not take place at an interface at which these different types of metals are in contact with each other, thus obtaining high reliability in long-term use. The semiconductor device includes: a contact electrode 16 in contact with silicon carbides 14, 18; and an upper electrode 19 electrically conductive to the contact electrode. The contact electrode 16 is formed of an alloy including titanium, aluminum, and silicon, the upper electrode 19 is formed of aluminum or an aluminum alloy, and the upper electrode achieves the electric conduction to the contact electrode with the upper electrode making contact with the contact electrode.
    Type: Application
    Filed: April 22, 2010
    Publication date: January 12, 2012
    Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Keiji Wada, Hideto Tamaso, Takeyoshi Masuda, Misako Honaga
  • Publication number: 20110297963
    Abstract: A silicon carbide semiconductor device is provided that includes a semiconductor layer made of silicon carbide and having a surface with a trench having a sidewall formed of a crystal plane tilted at an angle in a range of not less than 50° and not more than 65° relative to the {0001} plane, and an insulating film formed to contact the sidewall of the trench. A maximum value of the nitrogen concentration in a region within 10 nm from the interface between the sidewall of the trench and the insulating film is not less than 1×1021 cm?3, and the semiconductor device has a channel direction in a range of ±10° relative to the direction orthogonal to the <?2110> direction in the sidewall of the trench. A method of manufacturing the silicon carbide semiconductor device is also provided.
    Type: Application
    Filed: January 27, 2010
    Publication date: December 8, 2011
    Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Misako Honaga, Shin Harada
  • Publication number: 20110180812
    Abstract: A MOSFET which is a semiconductor device capable of achieving a stable reverse breakdown voltage and reduced on-resistance includes a SiC wafer of an n conductivity type, a plurality of p bodies of a p conductivity type formed to include a first main surface of the SiC wafer, and n+ source regions of the n conductivity type formed in regions surrounded by the plurality of p bodies, respectively, when viewed two-dimensionally. Each of the p bodies has a circular shape when viewed two-dimensionally, and each of the n+ source regions is arranged concentrically with each of the p bodies and has a circular shape when viewed two-dimensionally. Each of the plurality of p bodies is arranged to be positioned at a vertex of a regular hexagon when viewed two-dimensionally.
    Type: Application
    Filed: May 12, 2010
    Publication date: July 28, 2011
    Applicant: Sumitomo Electric Industries, Ltd.
    Inventors: Takeyoshi Masuda, Misako Honaga
  • Publication number: 20110175110
    Abstract: A MOSFET includes a silicon carbide (SiC) substrate having a main surface having an off angle of not less than 50° and not more than 65° relative to a {0001} plane; a semiconductor layer formed on the main surface of the SiC substrate; and an insulating film formed in contact with a surface of the semiconductor layer. When the insulating film has a thickness of not less than 30 nm and not more than 46 nm, the threshold voltage thereof is not more than 2.3V. When the insulating film has a thickness of more than 46 nm and not more than 100 nm, the threshold voltage thereof is more than 2.3 V and not more than 4.9 V.
    Type: Application
    Filed: March 23, 2010
    Publication date: July 21, 2011
    Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Keiji Wada, Shin Harada, Takeyoshi Masuda, Misako Honaga
  • Publication number: 20110169016
    Abstract: A MOSFET includes: a silicon carbide (SiC) substrate having a main surface having an off angle of not less than 50° and not more than 65° relative to a {0001} plane; a semiconductor layer formed on the main surface of the SiC substrate; and an insulating film formed in contact with a surface of the semiconductor layer. The MOSFET has a sub-threshold slope of not more than 0.4 V/Decade.
    Type: Application
    Filed: March 23, 2010
    Publication date: July 14, 2011
    Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Keiji Wada, Shin Harada, Takeyoshi Masuda, Misako Honaga