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: 9793343
    Abstract: To improve withstand capability of a semiconductor device during reverse recovery, provided is a semiconductor device including a semiconductor substrate having a first conduction type; a first region having a second conduction type that is formed in a front surface of the semiconductor substrate; a second region having a second conduction type that is formed adjacent to the first region in the front surface of the semiconductor substrate and has a higher concentration than the first region; a third region having a second conduction type that is formed adjacent to the second region in the front surface of the semiconductor substrate and has a higher concentration than the second region; an insulating film that covers a portion of the second region and the third region; and an electrode connected to the second region and the first region that are not covered by the insulating film.
    Type: Grant
    Filed: September 6, 2016
    Date of Patent: October 17, 2017
    Assignee: FUJI ELECTRIC., LTD.
    Inventors: Eri Ogawa, Hiroki Wakimoto, Misaki Takahashi, Yuichi Onozawa
  • Patent number: 9773923
    Abstract: Provided is a semiconductor device and a method for forming the same. 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 7, 2015
    Date of Patent: September 26, 2017
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Yuichi Onozawa, Takashi Yoshimura, Hiroshi Takishita
  • Publication number: 20170271447
    Abstract: Provided is a semiconductor device including a semiconductor substrate doped with impurities, a front surface-side electrode provided on a front surface side of the semiconductor substrate, a back surface-side electrode provided on a back surface side of the semiconductor substrate, wherein the semiconductor substrate has a peak region arranged on the back surface side of the semiconductor substrate and having one or more peaks of impurity concentration, a high concentration region arranged closer to the front surface than the peak region and having a gentler impurity concentration than the one or more peaks, and a low concentration region arranged closer to the front surface than the high concentration region and having a lower impurity concentration than the high concentration region.
    Type: Application
    Filed: May 30, 2017
    Publication date: September 21, 2017
    Inventors: Takahiro TAMURA, Yuichi ONOZAWA, Takashi YOSHIMURA, Hiroshi TAKISHITA, Akio YAMANO
  • Publication number: 20170271440
    Abstract: Provided is a guard ring section to which a fine processing is easily applied. Provided is a semiconductor device comprising: a semiconductor substrate; an active region formed in the semiconductor substrate; and a guard ring section formed more outside than the active region in the semiconductor substrate, wherein the guard ring section includes: a guard ring formed in a circular pattern on an upper surface of the semiconductor substrate; an interlayer insulating film formed above the guard ring; a field plate formed in a circular pattern along the guard ring and above the interlayer insulating film; and a tungsten plug formed in a circular pattern along the guard ring and penetrating the interlayer insulating film to connect the guard ring and the field plate.
    Type: Application
    Filed: March 1, 2017
    Publication date: September 21, 2017
    Inventors: Hiroyuki TANAKA, Kota OHI, Yuichi ONOZAWA, Yoshihiro IKURA, Kazutoshi Sugimura
  • Publication number: 20170263740
    Abstract: Provided is a semiconductor device comprising: a semiconductor substrate; a plurality of first trench portions formed at a front surface side of the semiconductor substrate and extending in a predetermined extending direction in a planar view; an emitter region of a first conductivity type formed between adjacent trenches of the plurality of first trench portions at the front surface side of the semiconductor substrate; a first contact region of a second conductivity type formed between the adjacent trenches of the plurality of first trench portions, the first contact region and the emitter region being arranged alternately in the extending direction; and a second contact region of a second conductivity type formed above the first contact region to be apart from the emitter region and having a higher doping concentration than the first contact region.
    Type: Application
    Filed: March 9, 2017
    Publication date: September 14, 2017
    Inventors: Yuichi ONOZAWA, Kota OHI, Tatsuya Naito, Misaki TAKAHASHI
  • Publication number: 20170250257
    Abstract: At edge termination region, a trench is disposed near an interface of an active region. Inside the trench, an embedded insulating film is embedded, and inside the embedded insulating film, a FP long in a direction of depth is disposed. The FP curves outwardly away from an inner side wall of the trench as a depth from a base front surface increases. At least near a bottom end of the FP, a distance between the FP and the inner side wall of the trench is greater than a width of the groove. The FP is connected to a front surface electrode that extends on the embedded insulating film. As a result, breakdown voltage may be enhanced, adverse effects of the surface charge may be reduced, and chip size may be further reduced.
    Type: Application
    Filed: March 30, 2017
    Publication date: August 31, 2017
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Wentao YANG, Johnny Kin On SIN, Yuichi ONOZAWA
  • Publication number: 20170250258
    Abstract: At edge termination region, a trench is disposed near an interface of an active region. Inside the trench, an embedded insulating film is embedded, and inside the embedded insulating film, a FP long in a direction of depth is disposed. The FP curves outwardly away from an inner sidewall of the trench as a depth from a base front surface increases. At least near a bottom end of the FP, a distance between the FP and the inner sidewall of trench is greater than a width of the groove. The FP is connected to a front surface electrode that extends on the embedded insulating film. As a result, breakdown voltage can be enhanced, adverse effects of the surface charge can be reduced, and chip size can be further reduced.
    Type: Application
    Filed: April 25, 2017
    Publication date: August 31, 2017
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Wentao YANG, Johnny Kin On SIN, Yuichi ONOZAWA, Kaname MITSUZUKA
  • Publication number: 20170236927
    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: Application
    Filed: May 1, 2017
    Publication date: August 17, 2017
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Yusuke KOBAYASHI, Yuichi ONOZAWA, Manabu TAKEI
  • Publication number: 20170162458
    Abstract: A method for manufacturing a semiconductor device includes: digging first and second trenches at the top surface of a plate-like base-body portion; forming an insulating film in the inside of each of the first and second trenches; laminating a conductive film on the top surface of the base-body portion so as to bury the first and second trenches with the conductive film via the insulating film; testing insulation-characteristics of the insulating film by applying a voltage between the conductive film and the bottom surface of the base-body portion; and after testing the insulation-characteristics, selectively removing the conductive film from the top surface of the base-body portion, so as to define a gate electrode in the first trench and an separated-electrode in the second trench, the separated-electrode being separated from the gate electrode.
    Type: Application
    Filed: February 21, 2017
    Publication date: June 8, 2017
    Inventor: Yuichi ONOZAWA
  • Patent number: 9673309
    Abstract: A p-layer on a surface layer of one of n? drift layers is separated into a p-base-region and a floating p-region by a plurality of trenches. A first gate electrode is disposed on a side wall of the trench on the p-base-region side via a first insulation film, and a shield electrode is disposed on a side wall of the trench on the floating p-region side via a second insulation film. Between the first gate electrode conductively connected to a gate runner via a contact plug embedded in a first contact hole and the shield electrode conductively connected to an emitter electrode via a contact plug embedded in a second contact hole, an insulation film reaches from the front surface of the substrate to the bottom surface of the trench. Hence, the fabrication process can be shortened to provide a highly reliable semiconductor device with low switching loss.
    Type: Grant
    Filed: August 31, 2015
    Date of Patent: June 6, 2017
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventor: Yuichi Onozawa
  • Patent number: 9634130
    Abstract: A semiconductor device includes stripe-shaped gate trench formed in one major surface of n-type drift layer, gate trench including gate polysilicon formed therein, and gate polysilicon being connected to a gate electrode; p-type base layer formed selectively in mesa region between adjacent gate trenches, p-type base layer including n-type emitter layer and connected to emitter electrode; one or more dummy trenches formed between p-type base layers adjoining to each other in the extending direction of gate trenches; and electrically conductive dummy polysilicon formed on an inner side wall of dummy trench with gate oxide film interposed between dummy polysilicon and dummy trench, dummy polysilicon being spaced apart from gate polysilicon. Dummy polysilicon may be connected to emitter electrode. The structure according to the invention facilitates providing an insulated-gate semiconductor device, the Miller capacitance of which is small, even when the voltage applied between the collector and emitter is low.
    Type: Grant
    Filed: July 14, 2015
    Date of Patent: April 25, 2017
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventor: Yuichi Onozawa
  • Publication number: 20170077217
    Abstract: To improve withstand capability of a semiconductor device during reverse recovery, provided is a semiconductor device including a semiconductor substrate having a first conduction type; a first region having a second conduction type that is formed in a front surface of the semiconductor substrate; a second region having a second conduction type that is formed adjacent to the first region in the front surface of the semiconductor substrate and has a higher concentration than the first region; a third region having a second conduction type that is formed adjacent to the second region in the front surface of the semiconductor substrate and has a higher concentration than the second region; an insulating film that covers a portion of the second region and the third region; and an electrode connected to the second region and the first region that are not covered by the insulating film.
    Type: Application
    Filed: September 6, 2016
    Publication date: March 16, 2017
    Inventors: Eri OGAWA, Hiroki WAKIMOTO, Misaki TAKAHASHI, Yuichi ONOZAWA
  • Publication number: 20170077004
    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: Application
    Filed: August 26, 2016
    Publication date: March 16, 2017
    Inventor: Yuichi ONOZAWA
  • Publication number: 20170018434
    Abstract: Protons are injected from a back surface side of a semiconductor substrate to repair both defects within the semiconductor substrate and also defects in a channel forming region on a front surface side of the semiconductor substrate. As a result, variation in gate threshold voltage is reduced and leak current when a reverse voltage is applied is reduced. Provided is a semiconductor device including a semiconductor substrate that includes an n-type impurity region containing protons, on a back surface side thereof; and a barrier metal that has an effect of shielding from protons, on a front surface side of the semiconductor substrate.
    Type: Application
    Filed: August 29, 2016
    Publication date: January 19, 2017
    Inventor: Yuichi ONOZAWA
  • Publication number: 20160372541
    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: August 31, 2016
    Publication date: December 22, 2016
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventor: Yuichi ONOZAWA
  • Publication number: 20160365434
    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: August 29, 2016
    Publication date: December 15, 2016
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Yusuke KOBAYASHI, Yuichi ONOZAWA, Manabu TAKEI, Akio NAKAGAWA
  • Patent number: 9478614
    Abstract: A semiconductor device has mesa form first and second p-type base regions and a floating p-type region provided in a surface layer of an n?-type drift layer. The first p-type base region and floating p-type region are separated by a first trench. The second p-type base region is separated from the floating p-type region by a second trench. The first and second p-type base regions are conductively connected to an emitter electrode. The floating p-type region is in a floating state electrically isolated from the emitter electrode. A first gate electrode is provided via a first gate insulating film inside the first trench. An emitter potential second gate electrode is provided via a second gate insulating film inside the second trench. Therefore, di/dt controllability when turning on the semiconductor device can be increased.
    Type: Grant
    Filed: August 10, 2015
    Date of Patent: October 25, 2016
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Yuichi Onozawa, Yusuke Kobayashi
  • 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
  • Patent number: 9461140
    Abstract: A p-type base layer is selectively formed on a surface of an n-type drift layer; an n-type source layer is selectively formed on a surface of the p-type base layer; and a p-type contact layer is formed to be in contact with the selectively-formed n-type source layer. A p-type counter layer is formed to be in contact with the n-type source layer, so as to overlap the p-type contact layer, so as to be separated from an interface where the p-type base layer and the gate oxide film are in contact with each other, and to be shallower than the p-type base layer. Accordingly, switching destruction caused by process defects in an insulated gate semiconductor device is reduced.
    Type: Grant
    Filed: June 11, 2015
    Date of Patent: October 4, 2016
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Yuichi Onozawa, Takashi Shiigi
  • Publication number: 20160284825
    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: June 6, 2016
    Publication date: September 29, 2016
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventor: Yuichi ONOZAWA