Patents by Inventor Naoyuki Ohse

Naoyuki Ohse 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: 20240405084
    Abstract: At a front surface of a silicon carbide base, an n?-type drift layer, a p-type base layer, a first n+-type source region, a second n+-type source region, and a trench that penetrates the first and the second n+-type source regions and the p-type base layer and reaches the n-type region are provided. In the trench, the gate electrode is provided via a gate insulating film, an interlayer insulating film is provided in the trench on the gate electrode.
    Type: Application
    Filed: August 13, 2024
    Publication date: December 5, 2024
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Yusuke KOBAYASHI, Naoyuki OHSE, Shinsuke HARADA
  • Publication number: 20240387723
    Abstract: Provided is a SiC semiconductor device that suppresses the decrease in the device design flexibility. The SiC semiconductor device includes a first SiC layer 14 containing SiC with a 4H structure, a second SiC layer 15 containing SiC with a 3C structure and stacked on the top face of the first SiC layer, a first conductivity type drift layer 2 provided in the first SiC layer, second conductivity type base regions 5a, 5b provided in the first SiC layer, first conductivity type main regions 6a, 6b including source extension regions 61a, 61b provided in the first SiC layer and source contact regions 62a, 62b provided in the second SiC layer, a gate insulating film 7b provided in a trench 7a penetrating the main region and the base region, a gate electrode 7c embedded in the trench, and a main electrode (11, 12) provided in contact with the source contact region.
    Type: Application
    Filed: February 26, 2024
    Publication date: November 21, 2024
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Tetsuya TAKAHASHI, Naoyuki OHSE
  • Publication number: 20240332363
    Abstract: A silicon carbide semiconductor device includes: a drift layer of a first conductivity-type; a base region of a second conductivity-type provided on a top surface side of the drift layer; a source contact region of the first conductivity-type including silicon carbide having a 3C-structure provided on a top surface side of the base region; a gate electrode buried inside a gate trench with a gate insulating film interposed; a main electrode buried inside a contact trench so as to be in contact with a side surface of the source contact region; and a base contact region of the second conductivity-type including silicon carbide having a 4H-structure so as to be in contact with a bottom surface of the contact trench, wherein the bottom surface of the contact trench is located at a position deeper than a bottom surface of the source contact region.
    Type: Application
    Filed: February 1, 2024
    Publication date: October 3, 2024
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventor: Naoyuki OHSE
  • Publication number: 20240321947
    Abstract: A silicon carbide semiconductor device includes: a drift layer of a first conductivity-type; a base region of a second conductivity-type provided on a top surface side of the drift layer; a source contact region of the first conductivity-type including silicon carbide having a 3C-structure provided on a top surface side of the base region; a gate electrode buried inside a trench with a gate insulating film interposed; a base contact region of the second conductivity-type including silicon carbide having a 4H-structure provided on the top surface side of the drift layer; a semiconductor region including silicon carbide having a 4H-structure provided between the source contact region and the base contact region; and a main electrode provided to be in contact with the source contact region.
    Type: Application
    Filed: January 25, 2024
    Publication date: September 26, 2024
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventor: Naoyuki OHSE
  • Patent number: 12094939
    Abstract: At a front surface of a silicon carbide base, an n?-type drift layer, a p-type base layer, a first n+-type source region, a second n+-type source region, and a trench that penetrates the first and the second n+-type source regions and the p-type base layer and reaches the n-type region are provided. In the trench, the gate electrode is provided via a gate insulating film, an interlayer insulating film is provided in the trench on the gate electrode, and a barrier metal is provided in the trench on the interlayer insulating film.
    Type: Grant
    Filed: May 31, 2018
    Date of Patent: September 17, 2024
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Yusuke Kobayashi, Naoyuki Ohse, Shinsuke Harada
  • Patent number: 12080762
    Abstract: A silicon carbide semiconductor device, including a semiconductor substrate containing silicon carbide, a bonding wire, and a surface electrode of an aluminum alloy containing silicon, the surface electrode being provided on a surface of the semiconductor substrate, and having a joint portion to which the bonding wire is bonded. The surface electrode has a plurality of silicon nodules formed therein, which include a number of the silicon nodules formed in the joint portion. One of the number of the silicon nodules is of a dendrite structure, and is included at an area percentage of at least 10% relative to a total area of the number of the silicon nodules in the joint portion.
    Type: Grant
    Filed: December 30, 2021
    Date of Patent: September 3, 2024
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Naoyuki Ohse, Makoto Utsumi
  • Publication number: 20240290842
    Abstract: A silicon carbide semiconductor device includes a starting substrate of a first conductivity type, a first semiconductor layer of the first conductivity type, a second semiconductor layer of a second conductivity type, a first semiconductor region of the first conductivity type, a gate insulating film, a gate electrode, an interlayer insulating film, an ohmic electrode, a barrier metal provided at the surface of the ohmic electrode and the surface of the interlayer insulating film, a surface electrode provided at the surface of the barrier metal, and a back electrode. The barrier metal has a three-layered structure including a first TiN film, a Ti film, and a second TiN film; the first TiN film contains TiN having a crystal grain size that is larger than a crystal grain size of TiN of the second TiN film.
    Type: Application
    Filed: October 30, 2023
    Publication date: August 29, 2024
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventor: Naoyuki OHSE
  • Publication number: 20240194781
    Abstract: A silicon carbide semiconductor device includes: a drift layer of a first conductivity-type, a base region of a second conductivity-type, and a main region of the first conductivity-type each including silicon carbide; a gate insulating film and a gate electrode buried inside a trench penetrating the main region and the base region; and a main electrode provided in contact with the main region, wherein the main region includes a source expansion part with a bottom surface in contact with the base region, and a source contact part having a 3C structure provided on a top surface side of the source expansion part so as to be in contact with the main electrode, and a top surface of the gate electrode is deeper than a bottom surface of the source contact part and is shallower than a bottom surface of the source expansion part.
    Type: Application
    Filed: October 23, 2023
    Publication date: June 13, 2024
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventor: Naoyuki OHSE
  • Patent number: 11929400
    Abstract: A method of manufacturing a silicon carbide semiconductor device, including forming a first-conductivity-type region in a SiC semiconductor substrate, selectively forming a plurality of second-conductivity-type regions in the first-conductivity-type region, forming an interlayer insulating film covering the first-conductivity-type region and the second-conductivity-type regions, selectively removing the interlayer insulating film to form a plurality of openings exposing the second-conductivity-type regions, forming, in each opening, a layered metal film having a cap film stacked on an aluminum film, thermally diffusing aluminum atoms in the aluminum film to thereby form a plurality of second-conductivity-type high-concentration regions, removing the layered metal film, selectively removing the interlayer insulating film to form a contact hole, forming a first electrode by sequentially stacking a titanium film and a metal film containing aluminum on the first surface of the semiconductor substrate in the conta
    Type: Grant
    Filed: June 28, 2021
    Date of Patent: March 12, 2024
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Naoyuki Ohse, Takahito Kojima
  • Patent number: 11527634
    Abstract: An SBD of a JBS structure has on a front side of a semiconductor substrate, nickel silicide films in ohmic contact with p-type regions and a FLR, and a titanium film forming a Schottky junction with an n?-type drift region. A thickness of each of the nickel silicide films is in a range from 300 nm to 700 nm. The nickel silicide films each has a first portion protruding from the front surface of the semiconductor substrate in a direction away from the front surface of the semiconductor substrate, and a second portion protruding in the semiconductor substrate from the front surface of the semiconductor substrate in a depth direction. A thickness of the first portion is equal to a thickness of the second portion. A width of the second portion is wider than a width of the first portion.
    Type: Grant
    Filed: April 19, 2021
    Date of Patent: December 13, 2022
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventor: Naoyuki Ohse
  • Publication number: 20220262905
    Abstract: A silicon carbide semiconductor device, including a semiconductor substrate containing silicon carbide, a bonding wire, and a surface electrode of an aluminum alloy containing silicon, the surface electrode being provided on a surface of the semiconductor substrate, and having a joint portion to which the bonding wire is bonded. The surface electrode has a plurality of silicon nodules formed therein, which include a number of the silicon nodules formed in the joint portion. One of the number of the silicon nodules is of a dendrite structure, and is included at an area percentage of at least 10% relative to a total area of the number of the silicon nodules in the joint portion.
    Type: Application
    Filed: December 30, 2021
    Publication date: August 18, 2022
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Naoyuki OHSE, Makoto UTSUMI
  • Patent number: 11411093
    Abstract: In a method of manufacturing a silicon carbide semiconductor device that is a silicon carbide diode having a JBS structure including a mixture of a Schottky junction and a pn junction and that maintains low forward voltage through a SBD structure and enhances surge current capability, nickel silicide films are formed in an oxide film by self-alignment by causing a semiconductor substrate and a metal material film to react with one another through two sessions of heat treatment including a low-temperature heat treatment and a high-temperature heat treatment, the metal material film including sequentially a first nickel film, an aluminum film, and a second nickel film, the first nickel film being in contact with an entire area of a connecting region of a FLR and p-type regions respectively exposed in openings of the oxide film.
    Type: Grant
    Filed: November 30, 2020
    Date of Patent: August 9, 2022
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Takahito Kojima, Naoyuki Ohse
  • Patent number: 11309438
    Abstract: A semiconductor device having, in a plan view, a termination region surrounding an active region. The semiconductor device includes a semiconductor substrate containing silicon carbide, a first-conductivity-type region provided in the semiconductor substrate at its first main surface, a plurality of first second-conductivity-type regions selectively formed in the semiconductor substrate at its first main surface, a plurality of silicide films respectively in ohmic contact with the first second-conductivity-type regions, a first electrode that is in contact with the silicide films to form ohmic regions, with the first second-conductivity-type regions to form non-operating regions, and with the first-conductivity-type region to form Schottky regions, a second electrode provided at a second main surface of the semiconductor substrate, and a second second-conductivity-type region provided in the termination region.
    Type: Grant
    Filed: December 1, 2020
    Date of Patent: April 19, 2022
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Naoyuki Ohse, Takahito Kojima, Yuichi Hashizume, Takafumi Uchida
  • Patent number: 11271118
    Abstract: A semiconductor device including a silicon carbide semiconductor substrate having a first-conductivity-type region at its first main surface. The semiconductor device has, at the first main surface, a plurality of first second-conductivity-type regions and a second second-conductivity-type region selectively provided in the first-conductivity-type region, respectively in an active region and a connecting region of the semiconductor device, and an oxide film provided in a termination region of the semiconductor device and having an inner end that faces the active region. A first silicide film is in ohmic contact with the first second-conductivity-type regions. A second silicide film is in contact with the inner end of the oxide film and in ohmic contact with the second second-conductivity-type region. The semiconductor device has a first electrode including a titanium film and a metal electrode film stacked sequentially on the first main surface, and a second electrode provided at a second main surface.
    Type: Grant
    Filed: July 29, 2020
    Date of Patent: March 8, 2022
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Naoyuki Ohse, Takahito Kojima
  • Patent number: 11233124
    Abstract: A silicon carbide semiconductor device includes plural p-type silicon carbide epitaxial layers provided on an n+-type silicon carbide substrate. In some of the p-type silicon carbide epitaxial layers, an n+ source region is provided in at least a region of an upper portion. The n+ source region includes a first portion that contains arsenic and a second portion that contains phosphorous.
    Type: Grant
    Filed: October 30, 2017
    Date of Patent: January 25, 2022
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Naoyuki Ohse, Makoto Utsumi, Yasuhiko Oonishi
  • Publication number: 20210391437
    Abstract: An SBD of a JBS structure has on a front side of a semiconductor substrate, nickel silicide films in ohmic contact with p-type regions and a FLR, and a titanium film forming a Schottky junction with an n?-type drift region. A thickness of each of the nickel silicide films is in a range from 300 nm to 700 nm. The nickel silicide films each has a first portion protruding from the front surface of the semiconductor substrate in a direction away from the front surface of the semiconductor substrate, and a second portion protruding in the semiconductor substrate from the front surface of the semiconductor substrate in a depth direction. A thickness of the first portion is equal to a thickness of the second portion. A width of the second portion is wider than a width of the first portion.
    Type: Application
    Filed: April 19, 2021
    Publication date: December 16, 2021
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventor: Naoyuki OHSE
  • Publication number: 20210328025
    Abstract: A method of manufacturing a silicon carbide semiconductor device, including forming a first-conductivity-type region in a SiC semiconductor substrate, selectively forming a plurality of second-conductivity-type regions in the first-conductivity-type region, forming an interlayer insulating film covering the first-conductivity-type region and the second-conductivity-type regions, selectively removing the interlayer insulating film to form a plurality of openings exposing the second-conductivity-type regions, forming, in each opening, a layered metal film having a cap film stacked on an aluminum film, thermally diffusing aluminum atoms in the aluminum film to thereby form a plurality of second-conductivity-type high-concentration regions, removing the layered metal film, selectively removing the interlayer insulating film to form a contact hole, forming a first electrode by sequentially stacking a titanium film and a metal film containing aluminum on the first surface of the semiconductor substrate in the conta
    Type: Application
    Filed: June 28, 2021
    Publication date: October 21, 2021
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Naoyuki OHSE, Takahito KOJIMA
  • Patent number: 11081564
    Abstract: A semiconductor device includes a first electrode, a silicon carbide substrate having a first surface electrically connected with the first electrode and a second surface opposite to the first surface, an ohmic junction layer disposed on the second surface, and a second electrode disposed on the ohmic junction layer. The ohmic junction layer has a first layer that is directly disposed on the second surface and includes a first silicide of titanium and a first silicide of a metal element other than titanium, and a second layer that is directly disposed on the first layer, includes a second silicide of titanium and a second silicide of the metal element, and has a lower titanium concentration than the first layer.
    Type: Grant
    Filed: December 27, 2019
    Date of Patent: August 3, 2021
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventor: Naoyuki Ohse
  • Publication number: 20210226031
    Abstract: In a method of manufacturing a silicon carbide semiconductor device that is a silicon carbide diode having a JBS structure including a mixture of a Schottky junction and a pn junction and that maintains low forward voltage through a SBD structure and enhances surge current capability, nickel silicide films are formed in an oxide film by self-alignment by causing a semiconductor substrate and a metal material film to react with one another through two sessions of heat treatment including a low-temperature heat treatment and a high-temperature heat treatment, the metal material film including sequentially a first nickel film, an aluminum film, and a second nickel film, the first nickel film being in contact with an entire area of a connecting region of a FLR and p-type regions respectively exposed in openings of the oxide film.
    Type: Application
    Filed: November 30, 2020
    Publication date: July 22, 2021
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Takahito KOJIMA, Naoyuki OHSE
  • Publication number: 20210175369
    Abstract: A semiconductor device having, in a plan view, a termination region surrounding an active region. The semiconductor device includes a semiconductor substrate containing silicon carbide, a first-conductivity-type region provided in the semiconductor substrate at its first main surface, a plurality of first second-conductivity-type regions selectively formed in the semiconductor substrate at its first main surface, a plurality of silicide films respectively in ohmic contact with the first second-conductivity-type regions, a first electrode that is in contact with the silicide films to form ohmic regions, with the first second-conductivity-type regions to form non-operating regions, and with the first-conductivity-type region to form Schottky regions, a second electrode provided at a second main surface of the semiconductor substrate, and a second second-conductivity-type region provided in the termination region.
    Type: Application
    Filed: December 1, 2020
    Publication date: June 10, 2021
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Naoyuki OHSE, Takahito KOJIMA, Yuichi HASHIZUME, Takafumi UCHIDA