Patents by Inventor Mitsuo Okamoto

Mitsuo Okamoto 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: 20210318346
    Abstract: An automated analyzing apparatus according to one embodiment comprises a barcode reader and a cylindrical lens. The barcode reader emits light toward a barcode attached to at least one of a specimen container storing a test sample, a reagent container storing a reagent to be reacted with the test sample, and a specimen rack housing a plurality of the specimen containers arranged in a line, and reads the barcode on the basis of reflected light of the applied light. The cylindrical lens is placed between at least one of the specimen container, the reagent container, and the specimen rack, and the barcode reader.
    Type: Application
    Filed: April 6, 2021
    Publication date: October 14, 2021
    Applicant: CANON MEDICAL SYSTEMS CORPORATION
    Inventors: Atsushi HOSOOKA, Naoto SATO, Reiko MARUYAMA, Mitsuo OKAMOTO, Masaaki SAITOU, Takahiro OMORI
  • Patent number: 10770548
    Abstract: A silicon nitride film having a thickness in a range from 1 [nm] to 3 [nm] is deposited on a front surface of a silicon carbide semiconductor base, by an ALD method. Next, on the silicon nitride film, for example, a silicon oxide film having a thickness in a range from 20 [nm] to 100 [nm] is deposited. After deposition of the silicon oxide film, for example, heat treatment is performed at a temperature in a range from 1100 degrees C. to 1350 degrees C., in a gas atmosphere that includes oxygen. By this heat treatment, nitrogen surface density of an interface of the silicon carbide semiconductor base and the silicon oxide film (gate insulating film) is increased, reducing interface state density of the interface of the silicon carbide semiconductor base and the silicon nitride film.
    Type: Grant
    Filed: February 15, 2019
    Date of Patent: September 8, 2020
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Tsuyoshi Araoka, Mitsuo Okamoto, Yohei Iwahashi
  • Patent number: 10600921
    Abstract: In forming an ohmic electrode on a back surface of an n-type SiC substrate, an n+-type semiconductor region is formed in a surface layer of the back surface of an n-type epitaxial substrate by ion implantation. In this ion implantation, the impurity concentration of the n+-type semiconductor region is a predetermined range and preferably a predetermined value or less, and an n-type impurity is implanted by acceleration energy of a predetermined range such that the n+-type semiconductor region has a predetermined thickness or less. Thereafter, a nickel layer and a titanium layer are sequentially formed on the surface of the n+-type semiconductor region, the nickel layer is heat treated to form a silicide, and the ohmic electrode formed from nickel silicide is formed. In this manner, a back surface electrode that has favorable properties can be formed while peeling of the back surface electrode can be suppressed.
    Type: Grant
    Filed: May 11, 2016
    Date of Patent: March 24, 2020
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Naoyuki Ohse, Fumikazu Imai, Tsunehiro Nakajima, Kenji Fukuda, Shinsuke Harada, Mitsuo Okamoto
  • Publication number: 20190267451
    Abstract: A silicon nitride film having a thickness in a range from 1 [nm] to 3 [nm] is deposited on a front surface of a silicon carbide semiconductor base, by an ALD method. Next, on the silicon nitride film, for example, a silicon oxide film having a thickness in a range from 20 [nm] to 100 [nm] is deposited. After deposition of the silicon oxide film, for example, heat treatment is performed at a temperature in a range from 1100 degrees C. to 1350 degrees C., in a gas atmosphere that includes oxygen. By this heat treatment, nitrogen surface density of an interface of the silicon carbide semiconductor base and the silicon oxide film (gate insulating film) is increased, reducing interface state density of the interface of the silicon carbide semiconductor base and the silicon nitride film.
    Type: Application
    Filed: February 15, 2019
    Publication date: August 29, 2019
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Tsuyoshi ARAOKA, Mitsuo OKAMOTO, Yohei IWAHASHI
  • 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: 10096680
    Abstract: A silicon carbide semiconductor device, including a silicon carbide semiconductor structure, an insulated gate structure including a gate insulating film contacting the silicon carbide semiconductor structure and a gate electrode formed on the gate insulating film, an interlayer insulating film covering the insulated gate structure, a metal layer provided on the interlayer insulating film for absorbing or blocking hydrogen, and a main electrode provided on the metal layer and electrically connected to the silicon carbide semiconductor structure.
    Type: Grant
    Filed: March 24, 2017
    Date of Patent: October 9, 2018
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Naoki Kumagai, Takashi Tsutsumi, Yoshiyuki Sakai, Yasuhiko Oonishi, Takumi Fujimoto, 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: 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
  • 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
  • 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
  • Patent number: 9923062
    Abstract: An infrared ray absorbing film is selectively formed on a surface of a silicon carbide semiconductor substrate in a predetermined area. The infrared ray absorbing film is composed of one of a multi-layered film of titanium nitride and titanium, a multi-layered film of molybdenum nitride and molybdenum, a multi-layered film of tungsten nitride and tungsten, or a multi-layered film of chromium nitride and chromium. An aluminum film and a nickel film are sequentially formed in this order on the silicon carbide semiconductor substrate in an area excluding the predetermined area in which the infrared ray absorbing film is formed. The silicon carbide semiconductor substrate is thereafter heated using a rapid annealing process with a predetermined heating rate to form an electrode. The rapid annealing process converts the nickel film into a silicide and, with the aluminum film, provides an electrode having ohmic contact.
    Type: Grant
    Filed: March 1, 2016
    Date of Patent: March 20, 2018
    Assignees: FUJI ELECTRIC CO., LTD., NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE AND TECHNOLOGY
    Inventors: Makoto Utsumi, Yoshiyuki Sakai, Kenji Fukuda, Shinsuke Harada, Mitsuo Okamoto
  • Publication number: 20170194438
    Abstract: A silicon carbide semiconductor device, including a silicon carbide semiconductor structure, an insulated gate structure including a gate insulating film contacting the silicon carbide semiconductor structure and a gate electrode formed on the gate insulating film, an interlayer insulating film covering the insulated gate structure, a metal layer provided on the interlayer insulating film for absorbing or blocking hydrogen, and a main electrode provided on the metal layer and electrically connected to the silicon carbide semiconductor structure.
    Type: Application
    Filed: March 24, 2017
    Publication date: July 6, 2017
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Naoki KUMAGAI, Takashi TSUTSUMI, Yoshiyuki SAKAI, Yasuhiko OONISHI, Takumi FUJIMOTO, Kenji FUKUDA, Shinsuke HARADA, Mitsuo OKAMOTO
  • 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
  • Patent number: 9490338
    Abstract: A silicon carbide vertical MOSFET having low ON-resistance and high blocking voltage is provided. For this, a first deposition film (2) of low concentration silicon carbide of a first conductivity type is formed on the surface of a high concentration silicon carbide substrate (1) of a first conductivity type. Formed on the first deposition film (2) is a second deposition film (31) that comprises a high concentration gate region of a second conductivity type, with a first region removed selectively. A third deposition film (32) formed on the second deposition film, which comprises a second region that is wider than the selectively removed first region, a high concentration source region (5) of a first conductivity type and a low concentration gate region (11) of a second conductivity type. A low concentration base region (4) of a first conductivity type is formed in contact with the first deposition film (2) in the first and second regions.
    Type: Grant
    Filed: December 31, 2013
    Date of Patent: November 8, 2016
    Assignees: National Institute of Advanced Industrial Science and Technology, SANYO ELECTRIC CO., LTD.
    Inventors: Shinsuke Harada, Tsutomu Yatsuo, Kenji Fukuda, Mitsuo Okamoto, Kazuhiro Adachi, Seiji Suzuki
  • Publication number: 20160254393
    Abstract: In forming an ohmic electrode on a back surface of an n-type SiC substrate, an n+-type semiconductor region is formed in a surface layer of the back surface of an n-type epitaxial substrate by ion implantation. In this ion implantation, the impurity concentration of the n+-type semiconductor region is a predetermined range and preferably a predetermined value or less, and an n-type impurity is implanted by acceleration energy of a predetermined range such that the n+-type semiconductor region has a predetermined thickness or less. Thereafter, a nickel layer and a titanium layer are sequentially formed on the surface of the n+-type semiconductor region, the nickel layer is heat treated to form a silicide, and the ohmic electrode formed from nickel silicide is formed. In this manner, a back surface electrode that has favorable properties can be formed while peeling of the back surface electrode can be suppressed.
    Type: Application
    Filed: May 11, 2016
    Publication date: September 1, 2016
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Naoyuki OHSE, Fumikazu IMAI, Tsunehiro NAKAJIMA, Kenji FUKUDA, Shinsuke HARADA, Mitsuo OKAMOTO
  • Publication number: 20160181376
    Abstract: An infrared ray absorbing film is selectively formed on a surface of a silicon carbide semiconductor substrate in a predetermined area. An aluminum film and a nickel film are sequentially formed in this order on the silicon carbide semiconductor substrate in an area excluding the predetermined area in which the infrared ray absorbing film is formed. The silicon carbide semiconductor substrate is thereafter heated using a rapid annealing process with a predetermined heating rate to form an electrode. The rapid annealing process converts the nickel film into a silicide and, with the aluminum film, provides an electrode having ohmic contact.
    Type: Application
    Filed: March 1, 2016
    Publication date: June 23, 2016
    Applicants: FUJI ELECTRIC CO., LTD., NATIONAL INSTITUTE OF ADVANCED INDUSTRIALSCIENCE AND TECHNOLOGY
    Inventors: Makoto UTSUMI, Yoshiyuki SAKAI, 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