Patents by Inventor Shoji Kitamura

Shoji Kitamura 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: 11728377
    Abstract: A semiconductor device, including a substrate of a first conductivity type, an active region and a termination structure portion formed on a front surface of the substrate, and a plurality of regions of a second conductivity type formed concentrically surrounding the periphery of the active region in the termination structure portion. Each region has a higher impurity concentration than one of the regions adjacent thereto on an outside thereof. The plurality regions include first and second semiconductor regions, and an intermediate region sandwiched between, and in contact with, the first and second semiconductor regions, and a third semiconductor region. The intermediate region includes a plurality of first subregions and a plurality of second subregions that are alternately arranged along a path in parallel to a boundary between the active region and the termination structure portion, the second subregions having a lower impurity concentration than the first subregions.
    Type: Grant
    Filed: October 7, 2021
    Date of Patent: August 15, 2023
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventor: Shoji Kitamura
  • Patent number: 11257900
    Abstract: A semiconductor device, including a substrate of a first conductivity type, an active region and a termination structure portion formed on a front surface of the substrate, and a plurality of regions of a second conductivity type formed concentrically surrounding the periphery of the active region in the termination structure portion. Each region has a higher impurity concentration than one of the regions adjacent thereto on an outside thereof. The plurality regions include first and second semiconductor regions, and an intermediate region sandwiched between, and in contact with, the first and second semiconductor regions. The intermediate region includes a plurality of first subregions and a plurality of second subregions that are alternately arranged along a path in parallel to a boundary between the active region and the termination structure portion, the second subregions having a lower impurity concentration than the first subregions.
    Type: Grant
    Filed: August 30, 2016
    Date of Patent: February 22, 2022
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventor: Shoji Kitamura
  • Publication number: 20220037462
    Abstract: A semiconductor device, including a substrate of a first conductivity type, an active region and a termination structure portion formed on a front surface of the substrate, and a plurality of regions of a second conductivity type formed concentrically surrounding the periphery of the active region in the termination structure portion. Each region has a higher impurity concentration than one of the regions adjacent thereto on an outside thereof. The plurality regions include first and second semiconductor regions, and an intermediate region sandwiched between, and in contact with, the first and second semiconductor regions, and a third semiconductor region. The intermediate region includes a plurality of first subregions and a plurality of second subregions that are alternately arranged along a path in parallel to a boundary between the active region and the termination structure portion, the second subregions having a lower impurity concentration than the first subregions.
    Type: Application
    Filed: October 7, 2021
    Publication date: February 3, 2022
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventor: Shoji KITAMURA
  • Patent number: 11087986
    Abstract: To enhance efficiency of a process of implanting impurities into a silicon carbide semiconductor layer. To provide a method of manufacturing a semiconductor device including a silicon carbide semiconductor layer, the method of manufacturing including: implanting impurities multiple times to an impurity implantation region in the silicon carbide semiconductor layer to different depths, with temperature of the silicon carbide semiconductor layer being set to be equal to or lower than 150° C. In the implanting, impurities may be implanted multiple times to the impurity implantation region to different depths, with temperature of the silicon carbide semiconductor layer being set to be equal to or higher than room temperature.
    Type: Grant
    Filed: March 30, 2020
    Date of Patent: August 10, 2021
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Katsushi Nishiyama, Masayuki Miyazaki, Shoji Kitamura
  • Patent number: 10727304
    Abstract: In an edge termination structure portion, first and second JTE regions are disposed concentrically surrounding an active region. Between the first and second JTE regions, a p-type electric field relaxation region is disposed that includes a first subregion and a second subregion alternately and repeatedly arranged concentrically surround a periphery of the first JTE region. An average impurity concentration of the electric field relaxation region is higher that the impurity concentration of the first JTE region adjacent on the inner side and lower than the impurity concentration of the second JTE region adjacent on the outer side. First subregions have widths that decrease the farther outward they are arranged. Second subregions have widths that are substantially the same independent of position. The first subregions and the first JTE region have equal impurity concentrations. The second subregions and the second JTE region have equal impurity concentrations.
    Type: Grant
    Filed: June 19, 2019
    Date of Patent: July 28, 2020
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventor: Shoji Kitamura
  • Publication number: 20200227261
    Abstract: To enhance efficiency of a process of implanting impurities into a silicon carbide semiconductor layer. To provide a method of manufacturing a semiconductor device including a silicon carbide semiconductor layer, the method of manufacturing including: implanting impurities multiple times to an impurity implantation region in the silicon carbide semiconductor layer to different depths, with temperature of the silicon carbide semiconductor layer being set to be equal to or lower than 150° C. In the implanting, impurities may be implanted multiple times to the impurity implantation region to different depths, with temperature of the silicon carbide semiconductor layer being set to be equal to or higher than room temperature.
    Type: Application
    Filed: March 30, 2020
    Publication date: July 16, 2020
    Inventors: Katsushi NISHIYAMA, Masayuki MIYAZAKI, Shoji KITAMURA
  • Patent number: 10700167
    Abstract: A semiconductor device includes a first semiconductor layer of a first conductivity type provided on a front surface of a silicon carbide semiconductor substrate of the first conductivity type, a first semiconductor region of a second conductivity type, a second semiconductor region of the second conductivity type and connected to the first semiconductor region, a first electrode forming a Schottky-contact with the first semiconductor layer and the first semiconductor region, and a second electrode forming an ohmic contact with the second semiconductor region. The second electrode has a Ti—Al alloy layer on a surface in contact with the first electrode. The second electrode further has therein a nickel silicide layer containing titanium.
    Type: Grant
    Filed: October 30, 2017
    Date of Patent: June 30, 2020
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Shoji Kitamura, Tsukasa Tashima, Kazuhiro Kitahara
  • Patent number: 10622212
    Abstract: To enhance efficiency of a process of implanting impurities into a silicon carbide semiconductor layer. To provide a method of manufacturing a semiconductor device including a silicon carbide semiconductor layer, the method of manufacturing including: implanting impurities multiple times to an impurity implantation region in the silicon carbide semiconductor layer to different depths, with temperature of the silicon carbide semiconductor layer being set to be equal to or lower than 150° C. In the implanting, impurities may be implanted multiple times to the impurity implantation region to different depths, with temperature of the silicon carbide semiconductor layer being set to be equal to or higher than room temperature.
    Type: Grant
    Filed: May 23, 2018
    Date of Patent: April 14, 2020
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Katsushi Nishiyama, Masayuki Miyazaki, Shoji Kitamura
  • Publication number: 20190305089
    Abstract: In an edge termination structure portion, first and second JTE regions are disposed concentrically surrounding an active region. Between the first and second JTE regions, a p-type electric field relaxation region is disposed that includes a first subregion and a second subregion alternately and repeatedly arranged concentrically surround a periphery of the first JTE region. An average impurity concentration of the electric field relaxation region is higher that the impurity concentration of the first JTE region adjacent on the inner side and lower than the impurity concentration of the second JTE region adjacent on the outer side. First subregions have widths that decrease the farther outward they are arranged. Second subregions have widths that are substantially the same independent of position. The first subregions and the first JTE region have equal impurity concentrations. The second subregions and the second JTE region have equal impurity concentrations.
    Type: Application
    Filed: June 19, 2019
    Publication date: October 3, 2019
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventor: Shoji KITAMURA
  • Patent number: 10396162
    Abstract: A silicon carbide semiconductor device includes a first semiconductor layer of a first conductivity type provided on a front surface of a silicon carbide semiconductor substrate of the first conductivity type; a first semiconductor region of a second conductivity type; a second semiconductor region of the second conductivity type, connected with the first semiconductor region; a first electrode forming a Schottky contact with a first semiconductor layer and a first semiconductor region; and a second electrode forming an ohmic contact with the second semiconductor region. A density of the second electrode is lower at a center portion of the silicon carbide semiconductor substrate and increases toward an outer peripheral side.
    Type: Grant
    Filed: June 26, 2017
    Date of Patent: August 27, 2019
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventor: Shoji Kitamura
  • Patent number: 10374043
    Abstract: In an edge termination structure portion, first and second JTE regions are disposed concentrically surrounding an active region. Between the first and second JTE regions, a p-type electric field relaxation region is disposed that includes a first subregion and a second subregion alternately and repeatedly arranged concentrically surround a periphery of the first JTE region. An average impurity concentration of the electric field relaxation region is higher that the impurity concentration of the first JTE region adjacent on the inner side and lower than the impurity concentration of the second JTE region adjacent on the outer side. First subregions have widths that decrease the farther outward they are arranged. Second subregions have widths that are substantially the same independent of position. The first subregions and the first JTE region have equal impurity concentrations. The second subregions and the second JTE region have equal impurity concentrations.
    Type: Grant
    Filed: December 1, 2016
    Date of Patent: August 6, 2019
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventor: Shoji Kitamura
  • Publication number: 20180301337
    Abstract: To enhance efficiency of a process of implanting impurities into a silicon carbide semiconductor layer. To provide a method of manufacturing a semiconductor device including a silicon carbide semiconductor layer, the method of manufacturing including: implanting impurities multiple times to an impurity implantation region in the silicon carbide semiconductor layer to different depths, with temperature of the silicon carbide semiconductor layer being set to be equal to or lower than 150° C. In the implanting, impurities may be implanted multiple times to the impurity implantation region to different depths, with temperature of the silicon carbide semiconductor layer being set to be equal to or higher than room temperature.
    Type: Application
    Filed: May 23, 2018
    Publication date: October 18, 2018
    Inventors: Katsushi NISHIYAMA, Masayuki MIYAZAKI, Shoji KITAMURA
  • Publication number: 20180158914
    Abstract: A semiconductor device includes a first semiconductor layer of a first conductivity type provided on a front surface of a silicon carbide semiconductor substrate of the first conductivity type, a first semiconductor region of a second conductivity type, a second semiconductor region of the second conductivity type and connected to the first semiconductor region, a first electrode forming a Schottky-contact with the first semiconductor layer and the first semiconductor region, and a second electrode forming an ohmic contact with the second semiconductor region. The second electrode has a Ti—Al alloy layer on a surface in contact with the first electrode. The second electrode further has therein a nickel silicide layer containing titanium.
    Type: Application
    Filed: October 30, 2017
    Publication date: June 7, 2018
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Shoji KITAMURA, Tsukasa TASHIMA, Kazuhiro KITAHARA
  • Publication number: 20180061951
    Abstract: A silicon carbide semiconductor device includes a first semiconductor layer of a first conductivity type provided on a front surface of a silicon carbide semiconductor substrate of the first conductivity type; a first semiconductor region of a second conductivity type; a second semiconductor region of the second conductivity type, connected with the first semiconductor region; a first electrode forming a Schottky contact with a first semiconductor layer and a first semiconductor region; and a second electrode forming an ohmic contact with the second semiconductor region. A density of the second electrode is lower at a center portion of the silicon carbide semiconductor substrate and increases toward an outer peripheral side.
    Type: Application
    Filed: June 26, 2017
    Publication date: March 1, 2018
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventor: Shoji KITAMURA
  • Patent number: 9680034
    Abstract: A simplified manufacturing process stably produces a semiconductor device with high electrical characteristics, wherein platinum acts as an acceptor. Plasma treatment damages the surface of an oxide film formed on a n? type drift layer deposited on an n+ type semiconductor substrate. The oxide film is patterned to have tapered ends. Two proton irradiations are carried out on the n? type drift layer with the oxide film as a mask to form a point defect region in the vicinity of the surface of the n? type drift layer. Silica paste containing 1% by weight platinum is applied to an exposed region of the n? type drift layer surface not covered with the oxide film. Heat treatment inverts the vicinity of the surface of the n? type drift layer to p-type by platinum atoms which are acceptors. A p-type inversion enhancement region forms a p-type anode region.
    Type: Grant
    Filed: March 30, 2016
    Date of Patent: June 13, 2017
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventor: Shoji Kitamura
  • Patent number: 9680033
    Abstract: A semiconductor device and a manufacturing method thereof is disclosed in which the semiconductor device includes a p-type anode layer formed by a transition metal acceptor transition, and the manufacturing process is significantly simplified without the breakdown voltage characteristics deteriorating. An inversion advancement region inverted to a p-type by a transition metal acceptor transition, and in which the acceptor transition is advanced by point defect layers, is formed on the upper surface of an n-type drift layer. The inversion advancement region configures a p-type anode layer of a semiconductor device of the invention. The transition metal is, for example, platinum or gold. An n-type semiconductor substrate with a concentration higher than that of the n-type drift layer is adjacent to the lower surface of the n-type drift layer.
    Type: Grant
    Filed: August 4, 2011
    Date of Patent: June 13, 2017
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventor: Shoji Kitamura
  • Publication number: 20170084701
    Abstract: In an edge termination structure portion, first and second JTE regions are disposed concentrically surrounding an active region. Between the first and second JTE regions, a p-type electric field relaxation region is disposed that includes a first subregion and a second subregion alternately and repeatedly arranged concentrically surround a periphery of the first JTE region. An average impurity concentration of the electric field relaxation region is higher that the impurity concentration of the first JTE region adjacent on the inner side and lower than the impurity concentration of the second JTE region adjacent on the outer side. First subregions have widths that decrease the farther outward they are arranged. Second subregions have widths that are substantially the same independent of position. The first subregions and the first JTE region have equal impurity concentrations. The second subregions and the second JTE region have equal impurity concentrations.
    Type: Application
    Filed: December 1, 2016
    Publication date: March 23, 2017
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventor: Shoji KITAMURA
  • Publication number: 20160372540
    Abstract: A semiconductor device, including a substrate of a first conductivity type, an active region and a termination structure portion formed on a front surface of the substrate, and a plurality of regions of a second conductivity type formed concentrically surrounding the periphery of the active region in the termination structure portion. Each region has a higher impurity concentration than one of the regions adjacent thereto on an outside thereof. The plurality regions include first and second semiconductor regions, and an intermediate region sandwiched between, and in contact with, the first and second semiconductor regions. The intermediate region includes a plurality of first subregions and a plurality of second subregions that are alternately arranged along a path in parallel to a boundary between the active region and the termination structure portion, the second subregions having a lower impurity concentration than the first subregions.
    Type: Application
    Filed: August 30, 2016
    Publication date: December 22, 2016
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventor: Shoji KITAMURA
  • Publication number: 20160307993
    Abstract: A defective layer is formed by ion implanting argon for a p+ anode layer from a front surface side of a base substrate. Here, the range of the argon is set to be shallower than the diffusion depth of the p+ anode layer such that platinum atoms are localized in an electron entering region near a pn junction of the p+ anode layer with an n? drift layer at a platinum diffusion step executed later. The platinum atoms in a platinum paste applied to the back surface of the base substrate are thereafter diffused in the p+ anode layer to be localized on a cathode side of the defective layer.
    Type: Application
    Filed: June 30, 2016
    Publication date: October 20, 2016
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Hidenao KURIBAYASHI, Shoji KITAMURA, Yuichi ONOZAWA
  • Publication number: 20160254148
    Abstract: A method of manufacturing a silicon carbide semiconductor device in which a first-conductivity-type silicon carbide semiconductor epitaxial layer is formed on a main surface of a first-conductivity-type silicon carbide semiconductor substrate, wherein the silicon carbide semiconductor device manufacturing method includes: a step for supplying strain energy to at least one of (i) a surface layer of the surface of the silicon carbide semiconductor substrate on which the silicon carbide semiconductor epitaxial layer is formed, and (ii) the surface of the silicon carbide semiconductor epitaxial layer, a step for forming a carbon film on the surface layer, and a step for forming a recrystallized layer by adding a heat treatment for recrystallizing the surface layer to which the strain energy is supplied.
    Type: Application
    Filed: September 26, 2014
    Publication date: September 1, 2016
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventor: Shoji KITAMURA