Patents by Inventor Yuichi Onozawa

Yuichi Onozawa 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: 10103256
    Abstract: A semiconductor device, including a first groove, a second groove and a first impurity region provided on a semiconductor substrate, a second impurity region provided in the first impurity region, a gate electrode provided in the first groove, a first insulating film provided between the first groove and the gate electrode, a second insulating film provided in the second groove, and a third insulating film provided astride tops of the first groove and the second groove. Each of the first and second insulating films has a lower half portion that is thicker than an upper half portion thereof. The lower half portions of the first and second insulating films are connected. The gate electrode has first and second portions thereof respectively contacting the lower and upper half portions of the first insulating film, a width of the first portion being narrower than a width of the second portion.
    Type: Grant
    Filed: May 1, 2017
    Date of Patent: October 16, 2018
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Yusuke Kobayashi, Yuichi Onozawa, Manabu Takei
  • Publication number: 20180233554
    Abstract: A semiconductor device is provided, including: a semiconductor substrate having an active area and an edge termination region; an upper electrode; an insulating film provided between the semiconductor substrate and the upper electrode and having a contact hole; a first conductivity-type drift region; a second conductivity-type base region; a second conductivity-type well region; and a second conductivity-type extension region formed extending in a direction toward the well region from the base region and separated from the upper electrode by the insulating film, wherein a sum of a first distance from an end portion of the contact hole closer to the well region to an end portion of the extension region closer to the well region and a second distance from the end portion of the extension region closer to the well region to the well region is smaller than a thickness of the semiconductor substrate in the active area.
    Type: Application
    Filed: February 15, 2018
    Publication date: August 16, 2018
    Inventors: Kaname Mitsuzuka, Yuichi Onozawa, Takahiro Tamura
  • Publication number: 20180219085
    Abstract: A semiconductor device of the present invention is structured such that in a surface layer of a first principal surface of a semiconductor substrate, an n-type drift layer, a p-type base layer, a p-type floating layer, an n-type emitter layer, an emitter electrode, and a trench in which a gate electrode is embedded with a gate insulating film is disposed therebetween are formed from a front surface side. Further, in a surface layer of a second principal surface of the semiconductor substrate, a p-type collector layer and a collector electrode contacting the-type collector layer are formed, and in a direction from the p-type collector layer toward a surface, an n-type selenium-doped field stop layer and an n-type proton doped field stop layer are formed, whereby IGBT turn OFF oscillation, oscillation at diode reverse recovery, and increases in leak voltage can be suppressed, and electrical loss can be reduced.
    Type: Application
    Filed: March 26, 2018
    Publication date: August 2, 2018
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventor: Yuichi ONOZAWA
  • Publication number: 20180219062
    Abstract: A method of manufacturing a semiconductor device, including implanting hydrogen atoms from a second principal surface of a semiconductor substrate, forming a plurality of second semiconductor layers that each have a carrier concentration higher than that of the first semiconductor layer and that have carrier concentration peak values at different depths from the second principal surface of the semiconductor substrate, applying a heat treatment process to promote generation of donors from the hydrogen atoms, implanting an impurity from the second principal surface of the semiconductor substrate, forming a third semiconductor layer in the semiconductor substrate at the second principal surface thereof, and applying another heat treatment process to locally heat the semiconductor substrate, so as to reduce the carrier concentration at an interface between the third semiconductor layer and the second semiconductor layer adjacent to the third semiconductor layer.
    Type: Application
    Filed: March 26, 2018
    Publication date: August 2, 2018
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventor: Yuichi ONOZAWA
  • Publication number: 20180190779
    Abstract: The position of the side wall of a metal electrode is precisely controlled and the coverage of a layer above the metal electrode is improved. A semiconductor device is provided, including: a semiconductor substrate; and a metal electrode formed above an upper surface of the semiconductor substrate, wherein a side wall of the metal electrode includes a lower portion contacting the semiconductor substrate, and an upper portion that is formed upper than the lower portion and has a smaller inclination relative to the upper surface of the semiconductor substrate than the lower portion. An active region formed in the semiconductor substrate is further included, and the metal electrode may be a field plate formed on an outer side relative to the active region on the upper surface of the semiconductor substrate. The upper portion of the side wall of the field plate may have an upward-convex shape.
    Type: Application
    Filed: February 20, 2018
    Publication date: July 5, 2018
    Inventors: Eri OGAWA, Yuichi ONOZAWA, Kazutoshi SUGIMURA, Hiroyuki TANAKA, Kota OHI, Yoshihiro IKURA
  • Publication number: 20180175216
    Abstract: A semiconductor device includes first to fourth semiconductor regions, and first and second electrodes. The second semiconductor region is selectively disposed in a surface layer of one main surface of the first semiconductor region. The first electrode is in contact with a contact region of the second semiconductor region. The third semiconductor region is disposed in a surface layer on another main surface of the first semiconductor region, and having an impurity concentration higher than that of the first semiconductor region. The second electrode is in contact with the third semiconductor region. The fourth semiconductor region of the second conductivity type is disposed in the first semiconductor region, and disposed closer to the one main surface than the third semiconductor region. The fourth semiconductor region is disposed at least within the contact region in a plan view.
    Type: Application
    Filed: February 5, 2018
    Publication date: June 21, 2018
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Yuichi ONOZAWA, Takashi YOSHIMURA, Hiroshi TAKISHITA
  • Publication number: 20180166279
    Abstract: A semiconductor device is provided. The semiconductor device includes: a first region formed on a front surface side of a semiconductor substrate; a drift region formed closer to a rear surface of the semiconductor substrate than the first region is; a buffer region that: is formed closer to the rear surface of the semiconductor substrate than the drift region is; and has one or more peaks of an impurity concentration that are higher than an impurity concentration of the drift region; and a lifetime killer that: is arranged on a rear surface side of the semiconductor substrate; and shortens a carrier lifetime, wherein a peak of a concentration of the lifetime killer is arranged between: a peak that is closest to a front surface of the semiconductor substrate among the peaks of the impurity concentration in the buffer region; and the rear surface of the semiconductor substrate.
    Type: Application
    Filed: January 24, 2018
    Publication date: June 14, 2018
    Inventors: Takahiro TAMURA, Yuichi ONOZAWA, Misaki TAKAHASHI
  • Publication number: 20180158815
    Abstract: A semiconductor device is provided that has a semiconductor substrate, a drift layer of a first conductivity type formed in the semiconductor substrate, a base region of a second conductivity type formed in the semiconductor substrate and above the drift layer, and an accumulation region of the first conductivity type provided between the drift layer and the base region and having an impurity concentration higher than an impurity concentration in the drift layer, wherein the accumulation region has a first accumulation region and a second accumulation region that is formed more shallowly than the first accumulation region is and on a side of a boundary with a region that is different from the accumulation region in a planar view.
    Type: Application
    Filed: February 1, 2018
    Publication date: June 7, 2018
    Inventors: Yuichi ONOZAWA, Kota OHI
  • Publication number: 20180158939
    Abstract: In mesa regions between adjacent trenches disposed in an n?-type drift layer and in which a first gate electrode is disposed via a first gate insulating film, a p-type base region and a floating p+-type region of which a surface is partially covered by a second gate electrode via a second gate insulating film are disposed. An emitter electrode contacts the p-type base region and an n+-type emitter region, and is electrically isolated from first and second gate electrodes and the floating p+-type region by an interlayer insulating film covering the first and second gate electrodes and a portion of the floating p+-type region not covered by the second gate electrode. Thus, turn-on dV/dt controllability by the gate resistance Rg may be improved.
    Type: Application
    Filed: January 11, 2018
    Publication date: June 7, 2018
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Yusuke KOBAYASHI, Yuichi ONOZAWA, Manabu TAKEI, Akio NAKAGAWA
  • Patent number: 9954053
    Abstract: A method of manufacturing a semiconductor device, including implanting hydrogen atoms from a second principal surface of a semiconductor substrate, forming a plurality of second semiconductor layers that each have a carrier concentration higher than that of the first semiconductor layer and that have carrier concentration peak values at different depths from the second principal surface of the semiconductor substrate, applying a heat treatment process to promote generation of donors from the hydrogen atoms, implanting an impurity from the second principal surface of the semiconductor substrate, forming a third semiconductor layer in the semiconductor substrate at the second principal surface thereof, and applying another heat treatment process to locally heat the semiconductor substrate, so as to reduce the carrier concentration at an interface between the third semiconductor layer and the second semiconductor layer adjacent to the third semiconductor layer.
    Type: Grant
    Filed: August 31, 2016
    Date of Patent: April 24, 2018
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventor: Yuichi Onozawa
  • Patent number: 9954086
    Abstract: A semiconductor device of the present invention is structured such that in a surface layer of a first principal surface of a semiconductor substrate, an n-type drift layer, a p-type base layer, a p-type floating layer, an n-type emitter layer, an emitter electrode, and a trench in which a gate electrode is embedded with a gate insulating film is disposed therebetween are formed from a front surface side. Further, in a surface layer of a second principal surface of the semiconductor substrate, a p-type collector layer and a collector electrode contacting the-type collector layer are formed, and in a direction from the p-type collector layer toward a surface, an n-type selenium-doped field stop layer and an n-type proton doped field stop layer are formed, whereby IGBT turn OFF oscillation, oscillation at diode reverse recovery, and increases in leak voltage can be suppressed, and electrical loss can be reduced.
    Type: Grant
    Filed: June 6, 2016
    Date of Patent: April 24, 2018
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventor: Yuichi Onozawa
  • Patent number: 9941395
    Abstract: An insulated gate semiconductor device includes a region that is provided between trenches in which a gate electrode is filled through a gate insulating film in a surface layer of a substrate, includes a p base region and an n+ emitter region, and comes into conductive contact with an emitter electrode and a p-type floating region that is electrically insulated by an insulating film which is interposed between the p-type floating region and the emitter electrode. The p-type floating region is deeper than the trench and has a lower impurity concentration than the p base region.
    Type: Grant
    Filed: April 9, 2014
    Date of Patent: April 10, 2018
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventor: Yuichi Onozawa
  • Publication number: 20180061935
    Abstract: To prevent an intermediate region from contacting a cathode electrode even if a cathode region is partially defective. There is provided a semiconductor device with a semiconductor substrate that has a field stop region where first impurities of a first conduction type are implanted, an intermediate region that is formed on a back surface side of the field stop region and where second impurities of a second conduction type are implanted, and a cathode region of the first conduction type that is formed on a back surface side of the intermediate region. In a back surface of the semiconductor substrate, a concentration of the first impurities is higher than a concentration of the second impurities.
    Type: Application
    Filed: October 24, 2017
    Publication date: March 1, 2018
    Inventors: Hiroki WAKIMOTO, Yuichi ONOZAWA, Takahiro TAMURA, Eri OGAWA
  • Patent number: 9899503
    Abstract: In mesa regions between adjacent trenches disposed in an n?-type drift layer and in which a first gate electrode is disposed via a first gate insulating film, a p-type base region and a floating p+-type region of which a surface is partially covered by a second gate electrode via a second gate insulating film are disposed. An emitter electrode contacts the p-type base region and an n+-type emitter region, and is electrically isolated from first and second gate electrodes and the floating p+-type region by an interlayer insulating film covering the first and second gate electrodes and a portion of the floating p+-type region not covered by the second gate electrode. Thus, turn-on dV/dt controllability by the gate resistance Rg may be improved.
    Type: Grant
    Filed: August 29, 2016
    Date of Patent: February 20, 2018
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Yusuke Kobayashi, Yuichi Onozawa, Manabu Takei, Akio Nakagawa
  • Patent number: 9893211
    Abstract: Provided is a semiconductor device manufacturing method. The device has a substrate including one and another surfaces. A first semiconductor region of a first conductivity type is formed in the substrate. A second conductivity type, second semiconductor region is provided in a first surface layer, that includes the one surface, of the substrate. A first electrode is in contact with the second semiconductor region to form a junction therebetween. A first conductivity type, third semiconductor region is provided in a second surface layer, that includes the another surface, of the substrate. The third semiconductor region has a higher impurity concentration than the first semiconductor region. A fourth semiconductor region of the second conductivity type is provided in the first semiconductor region at a location deeper than the third semiconductor region from the another surface. A second electrode is in contact with the third semiconductor region.
    Type: Grant
    Filed: August 24, 2017
    Date of Patent: February 13, 2018
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Yuichi Onozawa, Takashi Yoshimura, Hiroshi Takishita
  • Patent number: 9870965
    Abstract: Provided is a semiconductor device including a semiconductor substrate; a dummy trench that is formed on a front surface side of the semiconductor substrate; an emitter electrode that is formed above a front surface of the semiconductor substrate and includes a recessed portion that is a recess in an outer periphery thereof, as seen in a planar view; a dummy pad that is electrically connected to the dummy trench and has at least a portion thereof formed within the recessed portion, as seen in the planar view; and a dummy wire that electrically connects the emitter electrode and the dummy pad.
    Type: Grant
    Filed: August 26, 2016
    Date of Patent: January 16, 2018
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventor: Yuichi Onozawa
  • Publication number: 20180005829
    Abstract: Provided is a semiconductor device including: a semiconductor substrate doped with an impurity; a front-surface-side electrode provided at a side of a front surface of the semiconductor substrate; and a back-surface-side electrode provided at a side of a back surface of the semiconductor substrate; wherein the semiconductor substrate includes: a peak region arranged at the side of the back surface of the semiconductor substrate and having one or more peaks of an impurity concentration; a high concentration region arranged closer to the front surface than the peak region and having an impurity concentration more gently sloped than the one or more peaks; and a low concentration region arranged closer to the front surface than the high concentration region and having an impurity concentration lower than the impurity concentration of the high concentration region and a substrate concentration of the semiconductor substrate.
    Type: Application
    Filed: August 29, 2017
    Publication date: January 4, 2018
    Inventors: Hiroshi TAKISHITA, Takashi YOSHIMURA, Takahiro TAMURA, Yuichi ONOZAWA, Akio YAMANO
  • Publication number: 20170352768
    Abstract: Provided is a semiconductor device manufacturing method. The device has a substrate including one and another surfaces. A first semiconductor region of a first conductivity type is formed in the substrate. A second conductivity type, second semiconductor region is provided in a first surface layer, that includes the one surface, of the substrate. A first electrode is in contact with the second semiconductor region to form a junction therebetween. A first conductivity type, third semiconductor region is provided in a second surface layer, that includes the another surface, of the substrate. The third semiconductor region has a higher impurity concentration than the first semiconductor region. A fourth semiconductor region of the second conductivity type is provided in the first semiconductor region at a location deeper than the third semiconductor region from the another surface. A second electrode is in contact with the third semiconductor region.
    Type: Application
    Filed: August 24, 2017
    Publication date: December 7, 2017
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Yuichi ONOZAWA, Takashi YOSHIMURA, Hiroshi TAKISHITA
  • Patent number: 9818852
    Abstract: In some aspects of the invention, an n-type field-stop layer can have a total impurity of such an extent that a depletion layer spreading in response to an application of a rated voltage stops inside the n-type field-stop layer together with the total impurity of an n? type drift layer. Also, the n-type field-stop layer can have a concentration gradient such that the impurity concentration of the n-type field-stop layer decreases from a p+ type collector layer toward a p-type base layer, and the diffusion depth is 20 ?m or more. Furthermore, an n+ type buffer layer of which the peak impurity concentration can be higher than that of the n-type field-stop layer at 6×1015 cm?3 or more, and one-tenth or less of the peak impurity concentration of the p+ type collector layer, can be included between the n-type field-stop layer and p+ type collector layer.
    Type: Grant
    Filed: March 30, 2016
    Date of Patent: November 14, 2017
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Takashi Yoshimura, Hidenao Kuribayashi, Yuichi Onozawa, Hayato Nakano, Daisuke Ozaki
  • Patent number: 9812561
    Abstract: In some aspects of the invention, an n-type field-stop layer can have a total impurity of such an extent that a depletion layer spreading in response to an application of a rated voltage stops inside the n-type field-stop layer together with the total impurity of an n? type drift layer. Also, the n-type field-stop layer can have a concentration gradient such that the impurity concentration of the n-type field-stop layer decreases from a p+ type collector layer toward a p-type base layer, and the diffusion depth is 20 ?m or more. Furthermore, an n+ type buffer layer of which the peak impurity concentration can be higher than that of the n-type field-stop layer at 6×1015 cm?3 or more, and one-tenth or less of the peak impurity concentration of the p+ type collector layer, can be included between the n-type field-stop layer and p+ type collector layer.
    Type: Grant
    Filed: March 15, 2016
    Date of Patent: November 7, 2017
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Takashi Yoshimura, Hidenao Kuribayashi, Yuichi Onozawa, Hayato Nakano, Daisuke Ozaki