Patents by Inventor Ichiro Omura

Ichiro Omura 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: 20030201456
    Abstract: An insulated gate semiconductor device includes a first semiconductor layer of a first conductivity type. A plurality of second semiconductor layers of a second conductivity type selectively formed in a surface area of the first semiconductor layer. At least one third semiconductor layer of the first conductivity type is formed in a surface area of each of the second semiconductor layers. A fourth semiconductor layer is formed on a bottom of the first semiconductor layer. At least one fifth semiconductor layer of the second conductivity type is provided in the first semiconductor layer and connected to at least one of the plurality of second semiconductor layers. The fifth semiconductor layer has impurity concentration that is lower than that of the second semiconductor layers.
    Type: Application
    Filed: December 18, 2002
    Publication date: October 30, 2003
    Inventors: Wataru Saitoh, Ichiro Omura, Satoshi Aida
  • Publication number: 20030137037
    Abstract: A plurality of semiconductor chips is each arranged over a first conductor. Each of semiconductor chips has a first main electrode, a second main electrode and a control electrode. A second conductor is electrically connected to the second main electrode and has columns each having an upper surface arranged over each of the semiconductor chips and equal to the number of the semiconductor chips. A circuit board has openings penetrated by the columns and equal to the number of the semiconductor chips and has a first insulating film, a third conductive film arranged on a back surface of the first insulating film and electrically connected to the second conductor, and a fourth conductive film arranged on a surface of the first insulating film and electrically connected to the control electrode.
    Type: Application
    Filed: January 22, 2003
    Publication date: July 24, 2003
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Ichiro Omura, Tomokazu Domon, Eitaro Miyake
  • Publication number: 20030122222
    Abstract: A semiconductor device includes a diffusion area formed in a semiconductor layer of a first conductive type. The diffusion area comprises first and second impurity diffusion areas of the first and second conductive types, respectively. The diffusion area has a first and second areas which are defined by an impurity concentration of the first and second impurity diffusion areas. A junction between the first and second area is formed in a portion in which the first and second impurity diffusion areas overlap each other. A period of the impurity concentration, in a planar direction of the semiconductor layer, of the first or second area is smaller than the maximum width, in the planar direction of the semiconductor layer, of the first and second impurity diffusion areas constituting the first or second area.
    Type: Application
    Filed: December 26, 2002
    Publication date: July 3, 2003
    Inventors: Hideki Okumura, Hitoshi Kobayashi, Masanobu Tsuchitani, Akihiko Osawa, Wataru Saito, Masakazu Yamaguchi, Ichiro Omura
  • Patent number: 6548890
    Abstract: A press-contact type semiconductor device comprises: a plurality of semiconductor elements each of which has a first main electrode and a control electrode and a second main electrode; a second common main power source plate having the semiconductor elements positioned on a front surface thereof and electrically connected to the second main electrodes; a first common main power source plate arranged on the front surfaces of the semiconductor elements and electrically connected to the first main electrodes; a common control signal/main current plate arranged between semiconductor elements and including at least control signal wiring layers and main current wiring layers; conductive connectors for electrically connecting at least the main current wiring layers and the first common maim power source plate; and conductive elastic members for electrically connecting the main current wiring layers or the first common main power source plate to the conductive connectors by elasticity.
    Type: Grant
    Filed: January 22, 2002
    Date of Patent: April 15, 2003
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Eitaro Miyake, Yoshiki Endo, Ichiro Omura, Tomokazu Domon
  • Patent number: 6534998
    Abstract: Disclosed is a semiconductor device capable of stabilizing a gate voltage at high voltage and high current, protecting the device from breakdown by preventing current nonuniformity and oscillations and the like, thereby improving reliability, and a method for controlling the semiconductor device.
    Type: Grant
    Filed: November 21, 2000
    Date of Patent: March 18, 2003
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Ichiro Omura, Wolfgang Fichtner, Hiromichi Ohashi, Tsuneo Ogura, Hideaki Ninomiya
  • Publication number: 20020185705
    Abstract: A semiconductor device includes a drain layer, first and second drift layers, a RESURF layer, a drain electrode, a base layer, a source layer, a source electrode, and a gate electrode. The first drift layer is formed on the drain layer. The second drift layers and RESURF layers are formed on the first drift layer and periodically arranged in a direction perpendicular to the direction of depth. The RESURF layer forms a depletion layer in the second drift layer by a p-n junction including the second drift layer and RESURF layer. The impurity concentration in the first drift layer is different from that in the second drift layer. The drain electrode is electrically connected to the drain layer.
    Type: Application
    Filed: June 7, 2002
    Publication date: December 12, 2002
    Inventors: Wataru Saitoh, Ichiro Omura, Masakazu Yamaguchi, Satoshi Aida, Syotaro Ono
  • Publication number: 20020154482
    Abstract: A press-contact type semiconductor device comprises: a plurality of semiconductor elements each of which has a first main electrode and a control electrode and a second main electrode; a second common main power source plate having the semiconductor elements positioned on a front surface thereof and electrically connected to the second main electrodes; a first common main power source plate arranged on the front surfaces of the semiconductor elements and electrically connected to the first main electrodes; a common control signal/main current plate arranged between semiconductor elements and including at least control signal wiring layers and main current wiring layers; conductive connectors for electrically connecting at least the main current wiring layers and the first common maim power source plate; and conductive elastic members for electrically connecting the main current wiring layers or the first common main power source plate to the conductive connectors by elasticity.
    Type: Application
    Filed: January 22, 2002
    Publication date: October 24, 2002
    Inventors: Eitaro Miyake, Yoshiki Endo, Ichiro Omura, Tomokazu Domon
  • Patent number: 6465844
    Abstract: A power semiconductor device has a plurality of U-shaped buried layers buried in a drift layer and made of either an insulating material or a semiconductor having a wider bandgap than that of the semiconductor of the drift layer. The ratio of the product of the height H of the U-shaped buried layers and the arrangement pitch d to the spacing g between adjacent ones of the U-shaped buried layers is expressed as Hd/g≦13.2. With this configuration, a power semiconductor device having both a high breakdown voltage and a low on resistance can be realized.
    Type: Grant
    Filed: July 16, 2001
    Date of Patent: October 15, 2002
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Wataru Saito, Ichiro Omura
  • Publication number: 20020038887
    Abstract: This invention forms an N-type source layer by self-alignment in a vertical trench IGBT, vertical trench MOSFET, lateral trench IGBT, and lateral trench MOSFET. This decreases the diffused resistance in a P-type base layer to increase the latch-up breakdown voltage, and also lowers the ON voltage by micropatterning of the device.
    Type: Application
    Filed: September 19, 2001
    Publication date: April 4, 2002
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Hideaki Ninomiya, Tomoki Inoue, Ichiro Omura, Masakazu Yamaguchi
  • Publication number: 20020030237
    Abstract: A semiconductor element of this invention includes a drift layer of a first conductivity type formed on a semiconductor substrate of the first conductivity type, a well layer of a second conductivity type selectively formed in the surface of the drift layer, a source layer of the first conductivity type selectively formed in the surface of the well layer, a trench formed to reach at least the inside of the drift layer from the surface of the source layer through the well layer, a buried electrode formed in the trench through a first insulating film, and a control electrode formed on the drift layer, the well layer, and the source layer through a second insulating film.
    Type: Application
    Filed: June 28, 2001
    Publication date: March 14, 2002
    Inventors: Ichiro Omura, Wataru Saito, Tsuneo Ogura, Hiromichi Ohashi, Yoshihiko Saito, Kenichi Tokano
  • Publication number: 20020005549
    Abstract: A power semiconductor device has a plurality of U-shaped buried layers buried in a drift layer and made of either an insulating material or a semiconductor having a wider bandgap than that of the semiconductor of the drift layer. The ratio of the product of the height H of the U-shaped buried layers and the arrangement pitch d to the spacing g between adjacent ones of the U-shaped buried layers is expressed as Hd/g≦13.2. With this configuration, a power semiconductor device having both a high breakdown voltage and a low on resistance can be realized.
    Type: Application
    Filed: July 16, 2001
    Publication date: January 17, 2002
    Inventors: Wataru Saito, Ichiro Omura
  • Patent number: 6323717
    Abstract: According to this invention, there is provided a drive apparatus for a power device having high- and low-voltage main electrodes and a control electrode, including a circuit for decreasing a voltage of the control electrode to a voltage of the control electrode which is not higher than a threshold voltage of the power device before a voltage between the high- and low-voltage main electrodes enters an overshoot region in a case where the power device is to be turned off. Therefore, electron injection can be stopped before the voltage between the main electrodes rises, the stability of the current density can be improved, and current concentration, oscillation, and the like can be prevented to improve reliability.
    Type: Grant
    Filed: May 17, 1999
    Date of Patent: November 27, 2001
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Ichiro Omura, Suzuo Saito, Hiromichi Ohashi, Tomokazu Domon, Koichi Sugiyama, Simon Eicher, Tsuneo Ogura
  • Patent number: 6236069
    Abstract: Disclosed herein is an insulated-gate thyristor comprising a base layer of a first conductivity type, having first and second major surfaces, a first main-electrode region of the first conductivity type, formed in the first major surface of the base layer, a second main-electrode region of a second conductivity type, formed in the second major surface of the base layer, at least a pair of grooves extending from the first main-electrode region into the base layer, and opposing each other and spaced apart by a predetermined distance, insulated gate electrodes formed within the grooves, and a turn-off insulated-gate transistor structure for releasing carriers of the second conductivity type from the base layer.
    Type: Grant
    Filed: June 23, 1998
    Date of Patent: May 22, 2001
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Takashi Shinohe, Kazuya Nakayama, Minami Takeuchi, Masakazu Yamaguchi, Mitsuhiko Kitagawa, Ichiro Omura, Akio Nakagawa
  • Patent number: 6153896
    Abstract: Disclosed is a semiconductor device capable of stabilizing a gate voltage at high voltage and high current, protecting the device from breakdown by preventing current nonuniformity and oscillations and the like, thereby improving reliability, and a method for controlling the semiconductor device.
    Type: Grant
    Filed: March 13, 1998
    Date of Patent: November 28, 2000
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Ichiro Omura, Wolfgang Fichtner, Hiromichi Ohashi, Tsuneo Ogura, Hideaki Ninomiya
  • Patent number: 6137136
    Abstract: An injection enhanced insulated gate bipolar transistor is disclosed in which an average roughness of silicon on the side and bottom surfaces of trench grooves below a gate oxide film is made to be 0.6 nm or smaller. Irregular portions on the surface of silicon of the gate oxide film can be prevented. Thus, lowering of the gate breakdown voltage occurring because of dispersion of the thickness of the gate oxide film due to the irregular portions can be prevented.
    Type: Grant
    Filed: September 18, 1997
    Date of Patent: October 24, 2000
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Akihiro Yahata, Satoshi Urano, Tomoki Inoue, Ichiro Omura
  • Patent number: 6101114
    Abstract: A power conversion system that is capable of achieving low inductance, improving cooling performance and making the external shape of the entire system small, is achieved by combining a plurality of single phase inverter units. The inverter units include four device packages each of which is composed of four packaged power devices, two neutral point clamp diodes, two by-pass diode packages and clamp diode packages. Each by-pass diode packages is composed of two packaged by-pass diodes. The clamp diode packages are composed of packaged clamp diodes. The by-pass diode packages are provided on one of the wall surfaces of the clamp diode package, and the device packages are provided on an outside wall surface of the by-pass diode package.
    Type: Grant
    Filed: July 12, 1999
    Date of Patent: August 8, 2000
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kenji Kijima, Ichiro Omura, Suzuo Saito
  • Patent number: 6069371
    Abstract: A semiconductor rectifier in which the sum of loss during reverse recovery and loss in a conducting state can be suppressed even if the ratio between the periods of the conducting and blocking states varies and a method of driving the same are disclosed. A voltage is applied to a gate electrode formed in a face-to-face relationship with a base layer of a first conductivity type and an emitter layer of a second conductivity type with a gate insulation film interposed therebetween to form an inversion layer on the surface of the base layer of the first conductivity type. As a result, the base layer of the first conductivity type and the short layer of the first conductivity type are short-circuited to decrease the density of carriers in the base layer of the first conductivity type, loss during a reverse recovery operation can be suppressed.
    Type: Grant
    Filed: March 16, 1998
    Date of Patent: May 30, 2000
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Ichiro Omura, Tomoki Inoue
  • Patent number: 6049109
    Abstract: A power semiconductor device according to the present invention has an SOI substrate formed of a buried silicon oxide film having an uneven surface portion on the surface thereof and an n-type silicon active layer of low impurity concentration formed on the buried silicon oxide film. An n-type emitter layer and a p-type emitter layer are selectively formed in the surface area of the n-type silicon active layer. A cathode electrode and an anode electrode are respectively formed on the n-type emitter layer and p-type emitter layer. With the above structure, a power semiconductor device of high withstand voltage can be realized.
    Type: Grant
    Filed: September 11, 1995
    Date of Patent: April 11, 2000
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Ichiro Omura, Akio Nakagawa
  • Patent number: 6037632
    Abstract: A semiconductor device is disclosed, which comprises a first main electrode, a second main electrode, a high-resistance semiconductor layer of first conductivity type interposed between the first main electrode and the second main electrode, and at least a buried layer of second conductivity type selectively formed in the semiconductor layer, extending at substantially right angles to a line connecting the first and second main electrodes, comprising a plurality strips functioning as current paths and set at a potential different from a potential of any other electrode when a depletion layer extending from a region near the first main electrode reaches the buried layer.
    Type: Grant
    Filed: November 5, 1996
    Date of Patent: March 14, 2000
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Ichiro Omura, Tomoki Inoue, Hiromichi Ohashi
  • Patent number: 5969400
    Abstract: A semiconductor device includes a first semiconductor layer of a first conductivity type having first and second main surfaces, a second semiconductor layer of a second conductivity type selectively formed on the first main surface of the first semiconductor layer, the second semiconductor layer including a first region having a relatively high injection efficiency and a second region having a relatively low injection efficiency and the first region being surrounded by the second region, a third semiconductor layer of the first conductivity type formed on the second main surface of the first semiconductor layer, a first electrode selectively formed on the second semiconductor layer of the second conductivity type and connected to at least the first region, and a second electrode formed on the third semiconductor layer of the first conductivity type.
    Type: Grant
    Filed: March 12, 1996
    Date of Patent: October 19, 1999
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Takashi Shinohe, Yoshihiro Minami, Ichiro Omura