Patents by Inventor Youichi Makifuchi

Youichi Makifuchi 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: 10249497
    Abstract: A silicon carbide semiconductor device includes a silicon carbide semiconductor substrate of a first conductivity type, a gate insulating film provided on a front surface of the silicon carbide semiconductor substrate and including any one or a plurality of an oxide film, a nitride film, and an oxynitride film, and a gate electrode containing poly-silicon and provided on the gate insulating film. A concentration of fluorine in the gate insulating film at an interface with the silicon carbide semiconductor substrate is equal to or higher than 1×1019 atoms/cm3.
    Type: Grant
    Filed: August 30, 2017
    Date of Patent: April 2, 2019
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Tsuyoshi Araoka, Youichi Makifuchi, Takashi Tsutsumi, Mitsuo Okamoto, Kenji Fukuda
  • Patent number: 10163637
    Abstract: A silicon carbide semiconductor device, including a silicon carbide semiconductor substrate, and an insulating film formed on a front surface of the silicon carbide semiconductor substrate. The silicon carbide semiconductor substrate has fluorine implanted therein, a concentration of which is in a range of 2×1017/cm3 to 4×1018/cm3. A method of manufacturing the silicon carbide semiconductor device includes providing a silicon carbide semiconductor substrate, forming an oxide film on a front surface of the silicon carbide semiconductor substrate, removing a portion of the oxide film to expose the silicon carbide semiconductor substrate, implanting fluorine ions in the front surface of the silicon carbide semiconductor substrate through the removed portion of the oxide film, removing the oxide film after the fluorine ions are implanted, and forming an insulating film on the front surface of the silicon carbide semiconductor substrate after the oxide film is removed.
    Type: Grant
    Filed: August 30, 2017
    Date of Patent: December 25, 2018
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Tsuyoshi Araoka, Youichi Makifuchi, Masaki Miyazato, Takashi Tsutsumi, Mitsuo Okamoto, Kenji Fukuda
  • Patent number: 10103059
    Abstract: A method of manufacturing a silicon carbide semiconductor device includes forming on a front surface of a silicon carbide substrate of a first conductivity type, a silicon carbide layer of the first conductivity type of a lower concentration; selectively forming a region of a second conductivity type in a surface portion of the silicon carbide layer; selectively forming a source region of the first conductivity type in the region; forming a source electrode electrically connected to the source region; forming a gate insulating film on a surface of the region between the silicon carbide layer and the source region; forming a gate electrode on the gate insulating film; forming a drain electrode on a rear surface of the substrate; forming metal wiring comprising aluminum for the device, the metal wiring being connected to the source electrode; and performing low temperature nitrogen annealing after the metal wiring is formed.
    Type: Grant
    Filed: July 28, 2016
    Date of Patent: October 16, 2018
    Assignees: FUJI ELECTRIC CO., LTD., NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE AND TECHNOLOGY
    Inventors: Yoshiyuki Sugahara, Takashi Tsutsumi, Youichi Makifuchi, Tsuyoshi Araoka, Kenji Fukuda, Shinsuke Harada, Mitsuo Okamoto
  • Patent number: 9960040
    Abstract: In producing a MOS silicon carbide semiconductor device, after a first heat treatment (oxynitride) is performed in an oxidation atmosphere including nitrous oxide or nitric oxide, a second heat treatment including hydrogen is performed, whereby in the front surface of a SiC epitaxial substrate, a gate insulating film is formed. A gate electrode is formed and after an interlayer insulating film is formed, a third heat treatment is performed to bake the interlayer insulating film. After contact metal formation, a fourth heat treatment is performed to form a reactive layer of contact metal and the silicon carbide semiconductor. The third and fourth heat treatments are performed in an inert gas atmosphere of nitrogen, helium, argon, etc., and a manufacturing method of a silicon carbide semiconductor device is provided achieving a normally OFF characteristic and lowered interface state density.
    Type: Grant
    Filed: December 4, 2015
    Date of Patent: May 1, 2018
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Youichi Makifuchi, Mitsuo Okamoto
  • Publication number: 20180090320
    Abstract: A silicon carbide semiconductor device, including a silicon carbide semiconductor substrate, and an insulating film formed on a front surface of the silicon carbide semiconductor substrate. The silicon carbide semiconductor substrate has fluorine implanted therein, a concentration of which is in a range of 2×1017/cm3 to 4×1018/cm3. A method of manufacturing the silicon carbide semiconductor device includes providing a silicon carbide semiconductor substrate, forming an oxide film on a front surface of the silicon carbide semiconductor substrate, removing a portion of the oxide film to expose the silicon carbide semiconductor substrate, implanting fluorine ions in the front surface of the silicon carbide semiconductor substrate through the removed portion of the oxide film, removing the oxide film after the fluorine ions are implanted, and forming an insulating film on the front surface of the silicon carbide semiconductor substrate after the oxide film is removed.
    Type: Application
    Filed: August 30, 2017
    Publication date: March 29, 2018
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Tsuyoshi Araoka, Youichi Makifuchi, Masaki Miyazato, Takashi Tsutsumi, Mitsuo Okamoto, Kenji Fukuda
  • Publication number: 20180090321
    Abstract: A silicon carbide semiconductor device includes a silicon carbide semiconductor substrate of a first conductivity type, a gate insulating film provided on a front surface of the silicon carbide semiconductor substrate and including any one or a plurality of an oxide film, a nitride film, and an oxynitride film, and a gate electrode containing poly-silicon and provided on the gate insulating film. A concentration of fluorine in the gate insulating film at an interface with the silicon carbide semiconductor substrate is equal to or higher than 1×1019 atoms/cm3.
    Type: Application
    Filed: August 30, 2017
    Publication date: March 29, 2018
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Tsuyoshi ARAOKA, Youichi MAKIFUCHI, Takashi TSUTSUMI, Mitsuo OKAMOTO, Kenji FUKUDA
  • Patent number: 9922822
    Abstract: On a silicon carbide semiconductor substrate, heat treatment is performed after one layer or two or more layers of an oxide film, a nitride film, or an oxynitride film are formed as a gate insulating film. The heat treatment after the gate insulating film is formed is performed for a given period in an atmosphere that includes H2 and H2O without including O2. As a result, hydrogen or hydroxyl groups can be segregated in a limited region that includes the interface of the silicon carbide substrate and the gate insulating film. The width of the region to which the hydrogen or hydroxyl groups is segregated is from 0.5 nm to 10 nm. In such a manner, the interface state density can be lowered and high channel mobility can be realized.
    Type: Grant
    Filed: January 8, 2016
    Date of Patent: March 20, 2018
    Assignees: FUJI ELECTRIC CO., LTD., NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE AND TECHNOLOGY
    Inventors: Youichi Makifuchi, Takashi Tsutsumi, Tsuyoshi Araoka, Mitsuo Okamoto, Kenji Fukuda
  • Publication number: 20160336224
    Abstract: A method of manufacturing a silicon carbide semiconductor device includes forming on a front surface of a silicon carbide substrate of a first conductivity type, a silicon carbide layer of the first conductivity type of a lower concentration; selectively forming a region of a second conductivity type in a surface portion of the silicon carbide layer; selectively forming a source region of the first conductivity type in the region; forming a source electrode electrically connected to the source region; forming a gate insulating film on a surface of the region between the silicon carbide layer and the source region; forming a gate electrode on the gate insulating film; forming a drain electrode on a rear surface of the substrate; forming metal wiring comprising aluminum for the device, the metal wiring being connected to the source electrode; and performing low temperature nitrogen annealing after the metal wiring is formed.
    Type: Application
    Filed: July 28, 2016
    Publication date: November 17, 2016
    Applicants: FUJI ELECTRIC CO., LTD., NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE AND TECHNOLOGY
    Inventors: Yoshiyuki SUGAHARA, Takashi TSUTSUMI, Youichi MAKIFUCHI, Tsuyoshi ARAOKA, Kenji FUKUDA, Shinsuke HARADA, Mitsuo OKAMOTO
  • Publication number: 20160126092
    Abstract: On a silicon carbide semiconductor substrate, heat treatment is performed after one layer or two or more layers of an oxide film, a nitride film, or an oxynitride film are formed as a gate insulating film. The heat treatment after the gate insulating film is formed is performed for a given period in an atmosphere that includes H2 and H2O without including O2. As a result, hydrogen or hydroxyl groups can be segregated in a limited region that includes the interface of the silicon carbide substrate and the gate insulating film. The width of the region to which the hydrogen or hydroxyl groups is segregated is from 0.5 nm to 10 nm. In such a manner, the interface state density can be lowered and high channel mobility can be realized.
    Type: Application
    Filed: January 8, 2016
    Publication date: May 5, 2016
    Applicants: FUJI ELECTRIC CO., LTD., NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE AND TECHNOLOGY
    Inventors: Youichi MAKIFUCHI, Takashi TSUTSUMI, Tsuyoshi ARAOKA, Mitsuo OKAMOTO, Kenji FUKUDA
  • Publication number: 20160093494
    Abstract: In producing a MOS silicon carbide semiconductor device, after a first heat treatment (oxynitride) is performed in an oxidation atmosphere including nitrous oxide or nitric oxide, a second heat treatment including hydrogen is performed, whereby in the front surface of a SiC epitaxial substrate, a gate insulating film is formed. A gate electrode is formed and after an interlayer insulating film is formed, a third heat treatment is performed to bake the interlayer insulating film. After contact metal formation, a fourth heat treatment is performed to form a reactive layer of contact metal and the silicon carbide semiconductor. The third and fourth heat treatments are performed in an inert gas atmosphere of nitrogen, helium, argon, etc., and a manufacturing method of a silicon carbide semiconductor device is provided achieving a normally OFF characteristic and lowered interface state density.
    Type: Application
    Filed: December 4, 2015
    Publication date: March 31, 2016
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Youichi MAKIFUCHI, Mitsuo OKAMOTO
  • Patent number: 6932665
    Abstract: An organic EL display is formed by preparing an organic EL device substrate, and a combination of a transparent substrate and color conversion filter layers. An overcoat layer with a pillar is formed in a pillar mold formed by a stripping layer and a temporary substrate, and is adhered to the combination of the transparent substrate and the color conversion filter layer while curing the overcoat layer with the pillar at a predetermined temperature. The stripping layer is removed to detach the temporary substrate from the overcoat layer with the pillar. Finally, the overcoat layer with the pillar attached to the combination of the transparent substrate and the color conversion filter layers is attached to the organic EL device substrate.
    Type: Grant
    Filed: July 24, 2003
    Date of Patent: August 23, 2005
    Assignee: Fuji Electric Co., Ltd.
    Inventors: Youichi Makifuchi, Kenya Sakurai, Yukinori Kawamura
  • Publication number: 20050020174
    Abstract: An organic EL display is formed by preparing an organic EL device substrate, and a combination of a transparent substrate and color conversion filter layers. An overcoat layer with a pillar is formed in a pillar mold formed by a stripping layer and a temporary substrate, and is adhered to the combination of the transparent substrate and the color conversion filter layer while curing the overcoat layer with the pillar at a predetermined temperature. The stripping layer is removed to detach the temporary substrate from the overcoat layer with the pillar. Finally, the overcoat layer with the pillar attached to the combination of the transparent substrate and the color conversion filter layers is attached to the organic EL device substrate.
    Type: Application
    Filed: July 24, 2003
    Publication date: January 27, 2005
    Inventors: Youichi Makifuchi, Kenya Sakurai, Yukinori Kawamura