Patents by Inventor Katsuhiko Nishiwaki

Katsuhiko Nishiwaki 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: 9761681
    Abstract: The semiconductor device includes a gate insulation film covering inner surfaces of the first trench and the second trench, and an inner surface of an intersection, and a gate electrode provided in the first trench and the second trench, and facing the semiconductor substrate via the gate insulation film. Further, the semiconductor device includes an emitter region of an n-type provided in the semiconductor substrate, exposed on the front surface of the semiconductor substrate, being in contact with the gate insulation film in the second trench, and not being in contact with the gate insulation film provided on the inner surface of the intersection of the first trench and the second trench.
    Type: Grant
    Filed: March 27, 2015
    Date of Patent: September 12, 2017
    Assignee: TOYOTA JIDOSHA KABUSHIKI KAISHA
    Inventor: Katsuhiko Nishiwaki
  • Publication number: 20170069729
    Abstract: The semiconductor device includes a gate insulation film covering inner surfaces of the first trench and the second trench, and an inner surface of an intersection, and a gate electrode provided in the first trench and the second trench, and facing the semiconductor substrate via the gate insulation film. Further, the semiconductor device includes an emitter region of an n-type provided in the semiconductor substrate, exposed on the front surface of the semiconductor substrate, being in contact with the gate insulation film in the second trench, and not being in contact with the gate insulation film provided on the inner surface of the intersection of the first trench and the second trench.
    Type: Application
    Filed: March 27, 2015
    Publication date: March 9, 2017
    Applicant: TOYOTA JIDOSHA KABUSHIKI KAISHA
    Inventor: Katsuhiko NISHIWAKI
  • Publication number: 20160005843
    Abstract: By using an SOI substrate in which a front surface-side semiconductor layer, an insulating layer, and a back surface-side semiconductor layer are laminated in this order, vertical semiconductor devices are mass-produced. A process to be executed on a front surface of the SOI substrate is executed on the front surface. A back surface of the SOI substrate is etched so that the back surface-side semiconductor layer and the insulating layer are removed and a back surface of the front surface-side semiconductor layer is exposed. A process to be executed on the exposed back surface of the front surface-side semiconductor layer is executed on the back surface. A thickness of the front surface-side semiconductor layer of the SOI substrate can be accurately controlled, and the semiconductor devices having a semiconductor layer with the same thickness as the thickness of the front surface-side semiconductor layer are mass-produced.
    Type: Application
    Filed: February 12, 2013
    Publication date: January 7, 2016
    Applicant: TOYOTA JIDOSHA KABUSHIKI KAISHA
    Inventors: Yasuhiro HIRABAYASHI, Toru ONISHI, Katsuhiko NISHIWAKI, Jun SAITO
  • Patent number: 7579652
    Abstract: To present a semiconductor device capable of operating stably even at large current, by lessening current concentration into the corners of contact opening after switching off and suppressing local heat generation without raising the ON voltage. In an insulated gate transistor divided by P field region 111 and gate electrode 106, having N+ emitter region 104 and P+ emitter region 100, and controlling conduction between emitter and collector by voltage applied to gate electrode 106, the shape of contact opening 108 contacting emitter (N+ emitter region 104 and P+ emitter region 100) and emitter electrode is formed of curved lines at four corners. Hence, eliminating right-angle apex, hole current from the field region into the emitter electrode after switching off is prevented from concentrating at one point.
    Type: Grant
    Filed: June 10, 2004
    Date of Patent: August 25, 2009
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventor: Katsuhiko Nishiwaki
  • Publication number: 20060163653
    Abstract: To present a semiconductor device capable of operating stably even at large current, by lessening current concentration into the corners of contact opening after switching off and suppressing local heat generation without raising the ON voltage. In an insulated gate transistor divided by P field region 111 and gate electrode 106, having N+ emitter region 104 and P+ emitter region 100, and controlling conduction between emitter and collector by voltage applied to gate electrode 106, the shape of contact opening 108 contacting emitter (N+ emitter region 104 and P+ emitter region 100) and emitter electrode is formed of curved lines at four corners. Hence, eliminating right-angle apex, hole current from the field region into the emitter electrode after switching off is prevented from concentrating at one point.
    Type: Application
    Filed: June 10, 2004
    Publication date: July 27, 2006
    Inventor: Katsuhiko Nishiwaki
  • Patent number: 6930353
    Abstract: It is intended to provide a field-effective-type semiconductor device that can let low ON-resistance and non-excessive short-circuit current go together by effectively using its channel width and prevents device from destruction. In a field-effective-type semiconductor device, a semiconductor region arranged between gate electrodes 106 has stripe-patterned structure consisting of an N+ emitter region 104 and a P emitter region. The P emitter region is constituted by P channel region 103 of low concentration and P+ emitter region 100 of high concentration. The N+ emitter region 104, the P channel region 103, and the P+ emitter region 100 are in contact with the emitter electrode 109. Thereby, a channel width X is limited to the extent that is enough for ON current under normal operation state. That is, low ON-resistance and not excessive short-circuit current can go together in the field-effective-type semiconductor device.
    Type: Grant
    Filed: October 29, 2003
    Date of Patent: August 16, 2005
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Katsuhiko Nishiwaki, Tomoyoshi Kushida
  • Patent number: 6921941
    Abstract: It is intended to provide a high withstand voltage field effect type semiconductor device that relaxes electric fields in a semiconductor substrate without thickening thickness of a drift region and achieves withstand-ability against high voltage without sacrificing ON-voltage, switch-OFF characteristics, and miniaturization. A field effective type semiconductor device comprises emitter regions 100, 104 and gate electrodes 106 and the like on a surface (upper surface in FIG. 2), a collector region 101 and the like on the other surface (lower surface in FIG. 2), wherein N? field dispersion regions 111 of low impurity concentration are arranged between P body regions 103 facing to gate electrodes 106 and an N drift region 102 below P body regions 103. Thereby, electric field between collector and emitter is relaxed and high withstand voltage field effect type semiconductor device is realized.
    Type: Grant
    Filed: February 13, 2004
    Date of Patent: July 26, 2005
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Katsuhiko Nishiwaki, Tomoyoshi Kushida, Sachiko Kawaji
  • Publication number: 20040164349
    Abstract: It is intended to provide a high withstand voltage field effect type semiconductor device that relaxes electric fields in a semiconductor substrate without thickening thickness of a drift region and achieves withstand-ability against high voltage without sacrificing ON-voltage, switch-OFF characteristics, and miniaturization. A field effective type semiconductor device comprises emitter regions 100, 104 and gate electrodes 106 and the like on a surface (upper surface in FIG. 2), a collector region 101 and the like on the other surface (lower surface in FIG. 2), wherein N− field dispersion regions 111 of low impurity concentration are arranged between P body regions 103 facing to gate electrodes 106 and an N drift region 102 below P body regions 103. Thereby, electric field between collector and emitter is relaxed and high withstand voltage field effect type semiconductor device is realized.
    Type: Application
    Filed: February 13, 2004
    Publication date: August 26, 2004
    Applicant: TOYOTA JIDOSHA KABUSHIKI KAISHA
    Inventors: Katsuhiko Nishiwaki, Tomoyoshi Kushida, Sachiko Kawaji
  • Publication number: 20040084725
    Abstract: It is intended to provide a field-effective-type semiconductor device that can let low ON-resistance and non-excessive short-circuit current go together by effectively using its channel width and prevents device from destruction. In a field-effective-type semiconductor device, a semiconductor region arranged between gate electrodes 106 has stripe-patterned structure consisting of an N+ emitter region 104 and a P emitter region. The P emitter region is constituted by P channel region 103 of low concentration and P+ emitter region 100 of high concentration. The N+ emitter region 104, the P channel region 103, and the P+ emitter region 100 are in contact with the emitter electrode 109. Thereby, a channel width X is limited to the extent that is enough for ON current under normal operation state. That is, low ON-resistance and not excessive short-circuit current can go together in the field-effective-type semiconductor device.
    Type: Application
    Filed: October 29, 2003
    Publication date: May 6, 2004
    Applicant: Toyota Jidosha Kabushiki Kaisha
    Inventors: Katsuhiko Nishiwaki, Tomoyoshi Kushida
  • Patent number: 6518629
    Abstract: In a semiconductor device having high voltage resistance and low ON voltage characteristics, charge-storage regions (insulation layer) are formed in a drift region. Formed above the drift region are a channel region, an emitter region, trench-type gate electrodes, and an emitter electrode. Strips of the insulation layer extend in a direction intersecting a direction of extension of the gate electrodes, and form a stripe pattern. The insulation layer curbs extraction of holes into the channel region. Openings in the stripe pattern of the insulation layer form depletion layers.
    Type: Grant
    Filed: July 3, 2000
    Date of Patent: February 11, 2003
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Tomoyoshi Kushida, Katsuhiko Nishiwaki
  • Patent number: 6509610
    Abstract: A semiconductor device is formed such that a contact surface between a p-type high-concentration semiconductor region and an n-type high-concentration buffer region assumes a convexo-concave shape. This makes it possible to enlarge an area of the contact surface between the p-type high-concentration semiconductor region and the n-type high-concentration buffer region. As a result, holes are injected into an n-type low-concentration drift region from the p-type high-concentration semiconductor region with higher efficiency and with a less voltage drop between the pn-junction. Thus, effects of conductivity modulation can be achieved sufficiently and the on-resistance and the voltage drop of an IGBT can be lowered.
    Type: Grant
    Filed: July 18, 2001
    Date of Patent: January 21, 2003
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Akira Kawahashi, Katsuhiko Nishiwaki
  • Publication number: 20020013030
    Abstract: A semiconductor device is formed such that a contact surface between a p-type high-concentration semiconductor region and an n-type high-concentration buffer region assumes a convexo-concave shape. This makes it possible to enlarge an area of the contact surface between the p-type high-concentration semiconductor region and the n-type high-concentration buffer region. As a result, holes are injected into an n-type low-concentration drift region from the p-type high-concentration semiconductor region with higher efficiency and with a less voltage drop between the pn-junction. Thus, effects of conductivity modulation can be achieved sufficiently and the on-resistance and the voltage drop of an IGBT can be lowered.
    Type: Application
    Filed: July 18, 2001
    Publication date: January 31, 2002
    Applicant: TOYOTA JIDOSHA KABUSHIKI KAISHA
    Inventors: Akira Kawahashi, Katsuhiko Nishiwaki
  • Patent number: D276550
    Type: Grant
    Filed: May 17, 1982
    Date of Patent: November 27, 1984
    Assignee: Hitachi, Ltd.
    Inventors: Shuichi Kouno, Katsuhiko Nishiwaki, Kenichi Watanabe
  • Patent number: D278712
    Type: Grant
    Filed: November 26, 1982
    Date of Patent: May 7, 1985
    Assignee: Hitachi, Ltd.
    Inventors: Koushirou Adachi, Katsuhiko Nishiwaki, Motoake Sakamoto, Tamotsu Tsukaguchi, Mitsuo Miyamoto
  • Patent number: D279780
    Type: Grant
    Filed: March 24, 1983
    Date of Patent: July 23, 1985
    Assignee: Hitachi, Ltd.
    Inventors: Katsuhiko Nishiwaki, Akitaka Takeuchi, Hiroshi Endo, Akihiro Kawakami, Hideo Matsumura