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).
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Publication number: 20030201456Abstract: 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: ApplicationFiled: December 18, 2002Publication date: October 30, 2003Inventors: Wataru Saitoh, Ichiro Omura, Satoshi Aida
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Publication number: 20030137037Abstract: 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: ApplicationFiled: January 22, 2003Publication date: July 24, 2003Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Ichiro Omura, Tomokazu Domon, Eitaro Miyake
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Publication number: 20030122222Abstract: 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: ApplicationFiled: December 26, 2002Publication date: July 3, 2003Inventors: Hideki Okumura, Hitoshi Kobayashi, Masanobu Tsuchitani, Akihiko Osawa, Wataru Saito, Masakazu Yamaguchi, Ichiro Omura
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Patent number: 6548890Abstract: 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: GrantFiled: January 22, 2002Date of Patent: April 15, 2003Assignee: Kabushiki Kaisha ToshibaInventors: Eitaro Miyake, Yoshiki Endo, Ichiro Omura, Tomokazu Domon
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Patent number: 6534998Abstract: 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: GrantFiled: November 21, 2000Date of Patent: March 18, 2003Assignee: Kabushiki Kaisha ToshibaInventors: Ichiro Omura, Wolfgang Fichtner, Hiromichi Ohashi, Tsuneo Ogura, Hideaki Ninomiya
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Publication number: 20020185705Abstract: 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: ApplicationFiled: June 7, 2002Publication date: December 12, 2002Inventors: Wataru Saitoh, Ichiro Omura, Masakazu Yamaguchi, Satoshi Aida, Syotaro Ono
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Publication number: 20020154482Abstract: 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: ApplicationFiled: January 22, 2002Publication date: October 24, 2002Inventors: Eitaro Miyake, Yoshiki Endo, Ichiro Omura, Tomokazu Domon
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Patent number: 6465844Abstract: 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: GrantFiled: July 16, 2001Date of Patent: October 15, 2002Assignee: Kabushiki Kaisha ToshibaInventors: Wataru Saito, Ichiro Omura
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Publication number: 20020038887Abstract: 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: ApplicationFiled: September 19, 2001Publication date: April 4, 2002Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Hideaki Ninomiya, Tomoki Inoue, Ichiro Omura, Masakazu Yamaguchi
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Publication number: 20020030237Abstract: 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: ApplicationFiled: June 28, 2001Publication date: March 14, 2002Inventors: Ichiro Omura, Wataru Saito, Tsuneo Ogura, Hiromichi Ohashi, Yoshihiko Saito, Kenichi Tokano
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Publication number: 20020005549Abstract: 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: ApplicationFiled: July 16, 2001Publication date: January 17, 2002Inventors: Wataru Saito, Ichiro Omura
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Patent number: 6323717Abstract: 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: GrantFiled: May 17, 1999Date of Patent: November 27, 2001Assignee: Kabushiki Kaisha ToshibaInventors: Ichiro Omura, Suzuo Saito, Hiromichi Ohashi, Tomokazu Domon, Koichi Sugiyama, Simon Eicher, Tsuneo Ogura
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Patent number: 6236069Abstract: 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: GrantFiled: June 23, 1998Date of Patent: May 22, 2001Assignee: Kabushiki Kaisha ToshibaInventors: Takashi Shinohe, Kazuya Nakayama, Minami Takeuchi, Masakazu Yamaguchi, Mitsuhiko Kitagawa, Ichiro Omura, Akio Nakagawa
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Patent number: 6153896Abstract: 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: GrantFiled: March 13, 1998Date of Patent: November 28, 2000Assignee: Kabushiki Kaisha ToshibaInventors: Ichiro Omura, Wolfgang Fichtner, Hiromichi Ohashi, Tsuneo Ogura, Hideaki Ninomiya
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Patent number: 6137136Abstract: 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: GrantFiled: September 18, 1997Date of Patent: October 24, 2000Assignee: Kabushiki Kaisha ToshibaInventors: Akihiro Yahata, Satoshi Urano, Tomoki Inoue, Ichiro Omura
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Patent number: 6101114Abstract: 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: GrantFiled: July 12, 1999Date of Patent: August 8, 2000Assignee: Kabushiki Kaisha ToshibaInventors: Kenji Kijima, Ichiro Omura, Suzuo Saito
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Patent number: 6069371Abstract: 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: GrantFiled: March 16, 1998Date of Patent: May 30, 2000Assignee: Kabushiki Kaisha ToshibaInventors: Ichiro Omura, Tomoki Inoue
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Patent number: 6049109Abstract: 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: GrantFiled: September 11, 1995Date of Patent: April 11, 2000Assignee: Kabushiki Kaisha ToshibaInventors: Ichiro Omura, Akio Nakagawa
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Patent number: 6037632Abstract: 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: GrantFiled: November 5, 1996Date of Patent: March 14, 2000Assignee: Kabushiki Kaisha ToshibaInventors: Ichiro Omura, Tomoki Inoue, Hiromichi Ohashi
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Patent number: 5969400Abstract: 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: GrantFiled: March 12, 1996Date of Patent: October 19, 1999Assignee: Kabushiki Kaisha ToshibaInventors: Takashi Shinohe, Yoshihiro Minami, Ichiro Omura