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).
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Patent number: 10249497Abstract: 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: GrantFiled: August 30, 2017Date of Patent: April 2, 2019Assignee: FUJI ELECTRIC CO., LTD.Inventors: Tsuyoshi Araoka, Youichi Makifuchi, Takashi Tsutsumi, Mitsuo Okamoto, Kenji Fukuda
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Patent number: 10163637Abstract: 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: GrantFiled: August 30, 2017Date of Patent: December 25, 2018Assignee: FUJI ELECTRIC CO., LTD.Inventors: Tsuyoshi Araoka, Youichi Makifuchi, Masaki Miyazato, Takashi Tsutsumi, Mitsuo Okamoto, Kenji Fukuda
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Patent number: 10103059Abstract: 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: GrantFiled: July 28, 2016Date of Patent: October 16, 2018Assignees: FUJI ELECTRIC CO., LTD., NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE AND TECHNOLOGYInventors: Yoshiyuki Sugahara, Takashi Tsutsumi, Youichi Makifuchi, Tsuyoshi Araoka, Kenji Fukuda, Shinsuke Harada, Mitsuo Okamoto
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Patent number: 9960040Abstract: 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: GrantFiled: December 4, 2015Date of Patent: May 1, 2018Assignee: FUJI ELECTRIC CO., LTD.Inventors: Youichi Makifuchi, Mitsuo Okamoto
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Publication number: 20180090320Abstract: 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: ApplicationFiled: August 30, 2017Publication date: March 29, 2018Applicant: FUJI ELECTRIC CO., LTD.Inventors: Tsuyoshi Araoka, Youichi Makifuchi, Masaki Miyazato, Takashi Tsutsumi, Mitsuo Okamoto, Kenji Fukuda
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Publication number: 20180090321Abstract: 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: ApplicationFiled: August 30, 2017Publication date: March 29, 2018Applicant: FUJI ELECTRIC CO., LTD.Inventors: Tsuyoshi ARAOKA, Youichi MAKIFUCHI, Takashi TSUTSUMI, Mitsuo OKAMOTO, Kenji FUKUDA
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Patent number: 9922822Abstract: 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: GrantFiled: January 8, 2016Date of Patent: March 20, 2018Assignees: FUJI ELECTRIC CO., LTD., NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE AND TECHNOLOGYInventors: Youichi Makifuchi, Takashi Tsutsumi, Tsuyoshi Araoka, Mitsuo Okamoto, Kenji Fukuda
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Publication number: 20160336224Abstract: 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: ApplicationFiled: July 28, 2016Publication date: November 17, 2016Applicants: FUJI ELECTRIC CO., LTD., NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE AND TECHNOLOGYInventors: Yoshiyuki SUGAHARA, Takashi TSUTSUMI, Youichi MAKIFUCHI, Tsuyoshi ARAOKA, Kenji FUKUDA, Shinsuke HARADA, Mitsuo OKAMOTO
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Publication number: 20160126092Abstract: 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: ApplicationFiled: January 8, 2016Publication date: May 5, 2016Applicants: FUJI ELECTRIC CO., LTD., NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE AND TECHNOLOGYInventors: Youichi MAKIFUCHI, Takashi TSUTSUMI, Tsuyoshi ARAOKA, Mitsuo OKAMOTO, Kenji FUKUDA
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Publication number: 20160093494Abstract: 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: ApplicationFiled: December 4, 2015Publication date: March 31, 2016Applicant: FUJI ELECTRIC CO., LTD.Inventors: Youichi MAKIFUCHI, Mitsuo OKAMOTO
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Patent number: 6932665Abstract: 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: GrantFiled: July 24, 2003Date of Patent: August 23, 2005Assignee: Fuji Electric Co., Ltd.Inventors: Youichi Makifuchi, Kenya Sakurai, Yukinori Kawamura
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Publication number: 20050020174Abstract: 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: ApplicationFiled: July 24, 2003Publication date: January 27, 2005Inventors: Youichi Makifuchi, Kenya Sakurai, Yukinori Kawamura