Patents by Inventor Akimasa Kinoshita

Akimasa Kinoshita 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: 9252218
    Abstract: An Ni2Si layer and a TiC layer formed by sintering after deposition of a thin layer including Ni and a thin layer including Ti on a silicon carbide substrate have a structure in which the TiC layer is precipitated on a surface of the Ni2Si layer. A multilayer thin film including a Ti layer as a first thin film and an Ni layer as a second thin film is formed on the TiC layer surface in the structure. A TiC-derived C composition ratio is set to 15% or more at an interface between the TiC layer and the Ti layer of the multilayer thin film. As a result, a silicon carbide semiconductor element can be provided without occurrence of peeling after wafer dicing and subsequent picking up by a dicing tape.
    Type: Grant
    Filed: March 18, 2013
    Date of Patent: February 2, 2016
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Takashi Tsuji, Akimasa Kinoshita, Kenji Fukuda
  • Patent number: 9230958
    Abstract: A silicon carbide epitaxial layer formed by a low concentration wide band gap semiconductor of a first conductivity type is formed on the surface of a silicon carbide substrate formed by a high concentration wide band gap semiconductor of the first conductivity type. A Schottky electrode is formed on the silicon carbide epitaxial layer. The interface between the Schottky electrode and the silicon carbide epitaxial layer is used as a Schottky interface. Plural impurity regions of a second conductivity type are disposed at predetermined intervals in a lateral direction, in the silicon carbide epitaxial layer, at a position in the lower portion of the Schottky electrode in the depth direction. Because of the shape of the impurity regions, any leak current can be suppressed without raising the ON-resistance.
    Type: Grant
    Filed: March 14, 2013
    Date of Patent: January 5, 2016
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Akimasa Kinoshita, Takashi Tsuji, Kenji Fukuda
  • Publication number: 20150194313
    Abstract: An ohmic electrode (6) of a silicon carbide semiconductor apparatus is fabricated by forming an ohmic metal film on a silicon carbide substrate (1) by sputtering a target including a mixture or an alloy having therein nickel, and a metal(s) reducing the magnetic permeability of nickel and producing a carbide, where compositional ratios of the mixture or alloy are adjusted to predetermined compositional ratios, and by executing heat treatment for the ohmic metal film to calcinate the ohmic metal film. Thus, the ohmic electrode (6) that is for the silicon carbide semiconductor apparatus and capable of improving the use efficiency of the target can be manufactured, whose film thickness is even and that does not peel off.
    Type: Application
    Filed: March 18, 2013
    Publication date: July 9, 2015
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Mina Ryo, Shinichi Nakamata, Akimasa Kinoshita, Kenji Fukuda
  • Publication number: 20150144965
    Abstract: A p-type region, a p? type region, and a p+ type region are selectively disposed in a surface layer of a silicon carbide substrate base. The p-type region and the p? type region are disposed in a breakdown voltage structure portion that surrounds an active region. The p+ type region is disposed in the active region to make up a JBS structure. The p? type region surrounds the p-type region to make up a junction termination structure. A Schottky electrode forms a Schottky junction with an n-type silicon carbide epitaxial layer. The Schottky electrode overhangs an interlayer insulation film covering a portion of the p-type region and this overhanging portion acts as a field plate. The p+ type region has an acceptor concentration greater than or equal to a predetermined concentration and can make a forward surge current larger.
    Type: Application
    Filed: March 18, 2013
    Publication date: May 28, 2015
    Applicants: FUJI ELECTRIC CO., LTD., NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE
    Inventors: Takashi Tsuji, Akimasa Kinoshita, Noriyuki Iwamuro, Kenji Fukuda
  • Publication number: 20150129894
    Abstract: A silicon carbide epitaxial layer formed by a low concentration wide band gap semiconductor of a first conductivity type is formed on the surface of a silicon carbide substrate formed by a high concentration wide band gap semiconductor of the first conductivity type. A Schottky electrode is formed on the silicon carbide epitaxial layer. The interface between the Schottky electrode and the silicon carbide epitaxial layer is used as a Schottky interface. Plural impurity regions of a second conductivity type are disposed at predetermined intervals in a lateral direction, in the silicon carbide epitaxial layer, at a position in the lower portion of the Schottky electrode in the depth direction. Because of the shape of the impurity regions, any leak current can be suppressed without raising the ON-resistance.
    Type: Application
    Filed: March 14, 2013
    Publication date: May 14, 2015
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Akimasa Kinoshita, Takashi Tsuji, Kenji Fukuda
  • Publication number: 20150115285
    Abstract: P+ type regions and a p-type region are selectively disposed in a surface layer of a silicon carbide substrate base. The P+ type region is disposed in a breakdown voltage structure portion surrounding an active region. The P+ type region is disposed in the active region to make up a JBS structure. The p-type region surrounds the P+ type region to make up a junction termination (JTE) structure. A Schottky electrode forms a Schottky junction with an n-type silicon carbide epitaxial layer. The Schottky electrode overhangs an interlayer insulation film covering a portion of the P+ type region and the p-type region and this overhanging portion acts as a field plate. This enables the provision of a semiconductor device configured by using a wide band gap semiconductor capable of maintaining a high breakdown voltage with high reliability, and a method of fabricating thereof.
    Type: Application
    Filed: March 18, 2013
    Publication date: April 30, 2015
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Akimasa Kinoshita, Takashi Tsuji, Kenji Fukuda
  • Publication number: 20150076520
    Abstract: In a fabrication method of a silicon carbide semiconductor element including a drift layer playing a role of retaining a high withstand voltage on a front side of a semiconductor substrate of silicon carbide and including an ohmic electrode on a backside, dicing is added to form at least one dicing line in an element active region on a surface of the semiconductor substrate on a side opposite of the drift layer before forming the ohmic electrode on the backside of the semiconductor substrate. Thus, a silicon carbide semiconductor element and fabrication method thereof is provided such that even if the semiconductor substrate is made thinner to reduce the on-resistance, the strength of the substrate can be maintained and cracking of the wafer during wafer processing can be reduced.
    Type: Application
    Filed: March 18, 2013
    Publication date: March 19, 2015
    Applicants: FUJI ELECTRIC CO., LTD., NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE AND TECHNOLOGY
    Inventors: Takashi Tsuji, Akimasa Kinoshita, Kenji Fukuda
  • Publication number: 20150056786
    Abstract: Process (A) of preparing a silicon carbide substrate of a first conductivity type; process (B) of forming an epitaxial layer of the first conductivity type on one principal surface of the silicon carbide substrate; process (C) of forming on another principal surface of the silicon carbide substrate, a first metal layer; process (D) of heat treating the silicon carbide substrate after the process (C) to form an ohmic junction between the first metal layer and the other principal surface of the silicon carbide substrate, and a layer of a substance (10) highly cohesive with another metal on the first metal layer; and a process (E) of removing impurities and cleaning a surface of the first metal layer (8) on the other principal surface of the silicon carbide substrate (D), are performed. The heat treatment at process (D) is executed at a temperature of 1,100 degrees C. or more.
    Type: Application
    Filed: March 14, 2013
    Publication date: February 26, 2015
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Akimasa Kinoshita, Takashi Tsuji, Kenji Fukuda
  • Publication number: 20150048383
    Abstract: An Ni2Si layer and a TiC layer formed by sintering after deposition of a thin layer including Ni and a thin layer including Ti on a silicon carbide substrate have a structure in which the TiC layer is precipitated on a surface of the Ni2Si layer. A multilayer thin film including a Ti layer as a first thin film and an Ni layer as a second thin film is formed on the TiC layer surface in the structure. A TiC-derived C composition ratio is set to 15% or more at an interface between the TiC layer and the Ti layer of the multilayer thin film. As a result, a silicon carbide semiconductor element can be provided without occurrence of peeling after wafer dicing and subsequent picking up by a dicing tape.
    Type: Application
    Filed: March 18, 2013
    Publication date: February 19, 2015
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Takashi Tsuji, Akimasa Kinoshita, Kenji Fukuda
  • Publication number: 20140327019
    Abstract: A wide bandgap semiconductor device includes a first conductive type high-concentration wide bandgap semiconductor substrate, a first conductive type low-concentration wide bandgap semiconductor deposited film which is formed on the semiconductor substrate, a metal film which is formed on the semiconductor deposited film so that a Schottoky interface region is formed between the metal film and the semiconductor deposited film, and a second conductive type region which is formed in a region of the semiconductor deposited film corresponding to a peripheral portion of the metal film, wherein the Schottoky interface region in the semiconductor deposited film is surrounded by the second conductive type region so that periodic island regions are formed in the Schottoky interface region.
    Type: Application
    Filed: February 15, 2012
    Publication date: November 6, 2014
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Akimasa Kinoshita, Noriyuki Iwamuro
  • Publication number: 20140051241
    Abstract: A surface of a silicon carbide substrate on which a graphite layer is formed is covered with a metal layer which can form carbide. Then, the silicon carbide substrate is annealed to cause reaction between a metal in the metal layer which can form carbide and carbon in the graphite layer so as to change the graphite layer between the metal layer which can form carbide and the silicon carbide substrate to a metal carbide layer. Thus, the graphite layer is removed. The adhesion between the metal layer which can form carbide and the silicon carbide substrate can be improved so that separation of the metal layer which can form carbide can be suppressed. Graphite deposits can be suppressed due to the removal of the graphite layer so that separation of a wiring metal film formed on a surface of the metal layer which can form carbide can be suppressed.
    Type: Application
    Filed: April 6, 2012
    Publication date: February 20, 2014
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Akimasa Kinoshita, Takashi Tsuji, Fumikazu Imai