Patents by Inventor Norihito Tokura

Norihito Tokura 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: 9263267
    Abstract: In a manufacturing method of a silicon carbide semiconductor device, a semiconductor substrate made of single crystal silicon carbide is prepared. At a portion of the semiconductor substrate where a first electrode is to be formed, a metal thin film made of electrode material including an impurity is formed. After the metal thin film is formed, the first electrode including a metal reaction layer in which the impurity is introduced is formed by irradiating the metal thin film with a laser light.
    Type: Grant
    Filed: November 19, 2014
    Date of Patent: February 16, 2016
    Assignee: DENSO CORPORATION
    Inventors: Jun Kawai, Norihito Tokura, Kazuhiko Sugiura
  • Patent number: 9240445
    Abstract: A lateral semiconductor device includes a semiconductor layer, an insulating layer, and a resistive field plate. The semiconductor layer includes a first semiconductor region and a second semiconductor region at a surface portion, and the second semiconductor region makes a circuit around the first semiconductor region. The insulating layer is formed on a surface of the semiconductor layer and is disposed between the first and second semiconductor regions. The resistive field plate is formed on a surface of the insulating layer. Between the first and second semiconductor regions, a first section and a second section are adjacent to each other along a circumferential direction around the first semiconductor region. The resistive field plate includes first and second resistive field plate sections respectively formed in the first and second sections, and the first and second resistive field plate sections are separated from each other.
    Type: Grant
    Filed: May 10, 2012
    Date of Patent: January 19, 2016
    Assignee: DENSO CORPORATION
    Inventors: Takashi Suzuki, Norihito Tokura, Satoshi Shiraki, Shigeki Takahashi, Youichi Ashida, Akira Yamada
  • Patent number: 9214536
    Abstract: A lateral insulated gate bipolar transistor includes a semiconductor substrate including a drift layer, a collector region, a channel layer, an emitter region, a gate insulating layer, a gate electrode, a collector electrode, an emitter electrode, and a barrier layer. The barrier layer is disposed along either side of the collector region and is located to a depth deeper than a bottom of the channel layer. The barrier layer has an impurity concentration that is higher than an impurity concentration of the drift layer. The barrier layer has a first end close to the collector region and a second end far from the collector region. The first end is located between the channel layer and the collector region, and the second end is located on the bottom of the channel layer.
    Type: Grant
    Filed: November 12, 2013
    Date of Patent: December 15, 2015
    Assignee: DENSO CORPORATION
    Inventors: Shigeki Takahashi, Norihito Tokura, Satoshi Shiraki, Youichi Ashida, Akio Nakagawa
  • Publication number: 20150079781
    Abstract: In a manufacturing method of a silicon carbide semiconductor device, a semiconductor substrate made of single crystal silicon carbide is prepared. At a portion of the semiconductor substrate where a first electrode is to be formed, a metal thin film made of electrode material including an impurity is formed. After the metal thin film is formed, the first electrode including a metal reaction layer in which the impurity is introduced is formed by irradiating the metal thin film with a laser light.
    Type: Application
    Filed: November 19, 2014
    Publication date: March 19, 2015
    Inventors: Jun KAWAI, Norihito TOKURA, Kazuhiko SUGIURA
  • Patent number: 8941122
    Abstract: In a manufacturing method of a silicon carbide semiconductor device, a semiconductor substrate made of single crystal silicon carbide is prepared. At a portion of the semiconductor substrate where a first electrode is to be formed, a metal thin film made of electrode material including an impurity is formed. After the metal thin film is formed, the first electrode including a metal reaction layer in which the impurity is introduced is formed by irradiating the metal thin film with a laser light.
    Type: Grant
    Filed: April 2, 2013
    Date of Patent: January 27, 2015
    Assignee: DENSO CORPORATION
    Inventors: Jun Kawai, Norihito Tokura, Kazuhiko Sugiura
  • Patent number: 8854033
    Abstract: A semiconductor device having a lateral semiconductor element includes a semiconductor substrate, a first electrode on the substrate, a second electrode on the substrate, and an isolation structure located in the substrate to divide the substrate into a first island and a second island electrically insulated from the first island. The lateral semiconductor element includes a main cell located in the first island and a sense cell located in the second island. The main cell causes a first current to flow between the first electrode and the second electrode so that the first current flows in a lateral direction along the surface of the substrate. The first current is detected by detecting a second current flowing though the sense cell.
    Type: Grant
    Filed: June 1, 2011
    Date of Patent: October 7, 2014
    Assignee: DENSO CORPORATION
    Inventors: Satoshi Shiraki, Norihito Tokura, Shigeki Takahashi, Masahiro Yamamoto, Akira Yamada, Hiroyasu Kudo, Youichi Ashida, Akio Nakagawa
  • Publication number: 20140225234
    Abstract: A semiconductor device having a lateral diode includes a semiconductor layer, a first semiconductor region in the semiconductor layer, a contact region having an impurity concentration greater than that of the first semiconductor region, a second semiconductor region located in the semiconductor layer and separated from the contact region, a first electrode electrically connected through the contact region to the first semiconductor region, and a second electrode electrically connected to the second semiconductor region. The second semiconductor region includes a low impurity concentration portion, a high impurity concentration portion, and an extension portion. The second electrode forms an ohmic contact with the high impurity concentration portion. The extension portion has an impurity concentration greater than that of the low impurity concentration portion and extends in a thickness direction of the semiconductor layer.
    Type: Application
    Filed: April 22, 2014
    Publication date: August 14, 2014
    Applicant: DENSO CORPORATION
    Inventors: Takao YAMAMOTO, Norihito TOKURA, Hisato KATO, Akio NAKAGAWA
  • Patent number: 8791690
    Abstract: A semiconductor device having a lateral semiconductor element includes a semiconductor substrate, a first electrode on the substrate, a second electrode on the substrate, and an isolation structure located in the substrate to divide the substrate into a first island and a second island electrically insulated from the first island. The lateral semiconductor element includes a main cell located in the first island and a sense cell located in the second island. The main cell causes a first current to flow between the first electrode and the second electrode so that the first current flows in a lateral direction along the surface of the substrate. The first current is detected by detecting a second current flowing though the sense cell.
    Type: Grant
    Filed: June 1, 2011
    Date of Patent: July 29, 2014
    Assignee: DENSO CORPORATION
    Inventors: Satoshi Shiraki, Norihito Tokura, Shigeki Takahashi, Masahiro Yamamoto, Akira Yamada, Hiroyasu Kudo, Youichi Ashida, Akio Nakagawa
  • Patent number: 8742534
    Abstract: A semiconductor device having a lateral diode includes a semiconductor layer, a first semiconductor region in the semiconductor layer, a contact region having an impurity concentration greater than that of the first semiconductor region, a second semiconductor region located in the semiconductor layer and separated from the contact region, a first electrode electrically connected through the contact region to the first semiconductor region, and a second electrode electrically connected to the second semiconductor region. The second semiconductor region includes a low impurity concentration portion, a high impurity concentration portion, and an extension portion. The second electrode forms an ohmic contact with the high impurity concentration portion. The extension portion has an impurity concentration greater than that of the low impurity concentration portion and extends in a thickness direction of the semiconductor layer.
    Type: Grant
    Filed: August 3, 2011
    Date of Patent: June 3, 2014
    Assignee: DENSO CORPORATION
    Inventors: Takao Yamamoto, Norihito Tokura, Hisato Kato, Akio Nakagawa
  • Publication number: 20140070271
    Abstract: A lateral insulated gate bipolar transistor includes a semiconductor substrate including a drift layer, a collector region, a channel layer, an emitter region, a gate insulating layer, a gate electrode, a collector electrode, an emitter electrode, and a barrier layer. The barrier layer is disposed along either side of the collector region and is located to a depth deeper than a bottom of the channel layer. The barrier layer has an impurity concentration that is higher than an impurity concentration of the drift layer. The barrier layer has a first end close to the collector region and a second end far from the collector region. The first end is located between the channel layer and the collector region, and the second end is located on the bottom of the channel layer.
    Type: Application
    Filed: November 12, 2013
    Publication date: March 13, 2014
    Applicant: DENSO CORPORATION
    Inventors: Shigeki TAKAHASHI, Norihito TOKURA, Satoshi SHIRAKI, Youichi ASHIDA, Akio NAKAGAWA
  • Publication number: 20140048911
    Abstract: A lateral semiconductor device includes a semiconductor layer, an insulating layer, and a resistive field plate. The semiconductor layer includes a first semiconductor region and a second semiconductor region at a surface portion, and the second semiconductor region makes a circuit around the first semiconductor region. The insulating layer is formed on a surface of the semiconductor layer and is disposed between the first and second semiconductor regions. The resistive field plate is formed on a surface of the insulating layer. Between the first and second semiconductor regions, a first section and a second section are adjacent to each other along a circumferential direction around the first semiconductor region. The resistive field plate includes first and second resistive field plate sections respectively formed in the first and second sections, and the first and second resistive field plate sections are separated from each other.
    Type: Application
    Filed: May 10, 2012
    Publication date: February 20, 2014
    Applicant: DENSO CORPORATION
    Inventors: Takashi Suzuki, Norihito Tokura, Satoshi Shiraki, Shigeki Takahashi, Youichi Ashida, Akira Yamada
  • Patent number: 8604513
    Abstract: A semiconductor device includes: a SOI substrate; a semiconductor element having first and second impurity layers disposed in an active layer of the SOI substrate, the second impurity layer surrounding the first impurity layer; and multiple first and second conductive type regions disposed in a part of the active layer adjacent to an embedded insulation film of the SOI substrate. The first and second conductive type regions are alternately arranged. The first and second conductive type regions have a layout, which corresponds to the semiconductor element.
    Type: Grant
    Filed: September 23, 2010
    Date of Patent: December 10, 2013
    Assignee: DENSO CORPORATION
    Inventors: Youichi Ashida, Norihito Tokura, Shigeki Takahashi, Yoshiaki Nakayama, Satoshi Shiraki, Kouji Senda
  • Publication number: 20130285070
    Abstract: In a manufacturing method of a silicon carbide semiconductor device, a semiconductor substrate made of single crystal silicon carbide is prepared. At a portion of the semiconductor substrate where a first electrode is to be formed, a metal thin film made of electrode material including an impurity is formed. After the metal thin film is formed, the first electrode including a metal reaction layer in which the impurity is introduced is formed by irradiating the metal thin film with a laser light.
    Type: Application
    Filed: April 2, 2013
    Publication date: October 31, 2013
    Inventors: Jun KAWAI, Norihito TOKURA, Kazuhiko SUGIURA
  • Patent number: 8476673
    Abstract: A diode has a semiconductor layer and cathode and anode electrodes on a surface of the semiconductor layer. The semiconductor layer has cathode and anode regions respectively contacting the cathode and anode electrodes. The anode region has a first diffusion region having high surface concentration, a second diffusion region having intermediate surface concentration, and a third diffusion region having low surface concentration. The first diffusion region is covered with the second and third diffusion regions. The second diffusion region has a first side surface facing the cathode region, a second side surface opposite to the cathode region, and a bottom surface extending between the first and second side surfaces. The third diffusion region covers at least one of the first corner part connecting the first side surface with the bottom surface and the second corner part connecting the second side surface with the bottom surface.
    Type: Grant
    Filed: November 15, 2011
    Date of Patent: July 2, 2013
    Assignee: DENSO CORPORATION
    Inventors: Norihito Tokura, Satoshi Shiraki, Shigeki Takahashi, Shinya Sakurai, Takashi Suzuki
  • Patent number: 8354691
    Abstract: A N-channel lateral insulated-gate bipolar transistor includes a semiconductor substrate, a drift layer, a collector region, a channel layer, an emitter region, a gate insulation film, a gate electrode, a collector electrode, an emitter electrode. The collector region includes a high impurity concentration region having a high impurity concentration and a low impurity concentration region having a lower impurity concentration than the high impurity concentration region. The collector electrode is in ohmic contact with the high impurity concentration region and in schottky contact with the low impurity concentration region.
    Type: Grant
    Filed: September 7, 2011
    Date of Patent: January 15, 2013
    Assignee: DENSO CORPORATION
    Inventors: Norihito Tokura, Shigeki Takahashi, Youichi Ashida, Akio Nakagawa
  • Publication number: 20120139079
    Abstract: A diode has a semiconductor layer and cathode and anode electrodes on a surface of the semiconductor layer. The semiconductor layer has cathode and anode regions respectively contacting the cathode and anode electrodes. The anode region has a first diffusion region having high surface concentration, a second diffusion region having intermediate surface concentration, and a third diffusion region having low surface concentration. The first diffusion region is covered with the second and third diffusion regions. The second diffusion region has a first side surface facing the cathode region, a second side surface opposite to the cathode region, and a bottom surface extending between the first and second side surfaces. The third diffusion region covers at least one of the first corner part connecting the first side surface with the bottom surface and the second corner part connecting the second side surface with the bottom surface.
    Type: Application
    Filed: November 15, 2011
    Publication date: June 7, 2012
    Applicant: DENSO CORPORATION
    Inventors: Norihito TOKURA, Satoshi Shiraki, Shigeki Takahashi, Shinya Sakurai, Takashi Suzuki
  • Publication number: 20120119318
    Abstract: In a semiconductor device in which a first electrode and a second electrode are disposed on a surface of a first conductivity-type semiconductor layer of a semiconductor substrate and a lateral element is formed to cause an electric current between the first electrode and the second electrode, a scroll-shaped resistive field plate is disposed on the semiconductor layer across an insulation film. The resistive field plate extends toward the second electrode while surrounding a periphery of the first electrode in a scroll shape. A resistance value of a total resistance of the resistive field plate is in a range between 90 k? and 90 M?.
    Type: Application
    Filed: November 14, 2011
    Publication date: May 17, 2012
    Applicant: DENSO CORPORATION
    Inventors: Norihito TOKURA, Takao Yamamoto, Hisato Kato, Kouji Senda, Akio Nakagawa
  • Patent number: 8179106
    Abstract: A synchronous-rectifier type DC-DC converter includes a high-side main switch element, a low-side rectifying switch element, and a control drive circuit. The rectifying switch element includes a rectifying transistor element and a rectifying diode element connected in antiparallel with the rectifying transistor element. The control drive circuit detects an input voltage to the main switch element and determines the input voltage or a rate of increase in the input voltage. When the determined value exceeds a predetermined reference value, a complementary ON/OFF operation of the main switch element and the rectifying transistor element is released, and a state where both the main switch element and the rectifying transistor element are kept OFF for a time period that is longer than a dead-time during the complementary ON/OFF operation is set.
    Type: Grant
    Filed: September 3, 2009
    Date of Patent: May 15, 2012
    Assignee: Denso Corporation
    Inventors: Norihito Tokura, Hisato Kato, Norikazu Kanatake, Masakiyo Horie
  • Publication number: 20120061726
    Abstract: A N-channel lateral insulated-gate bipolar transistor includes a semiconductor substrate, a drift layer, a collector region, a channel layer, an emitter region, a gate insulation film, a gate electrode, a collector electrode, an emitter electrode. The collector region includes a high impurity concentration region having a high impurity concentration and a low impurity concentration region having a lower impurity concentration than the high impurity concentration region. The collector electrode is in ohmic contact with the high impurity concentration region and in schottky contact with the low impurity concentration region.
    Type: Application
    Filed: September 7, 2011
    Publication date: March 15, 2012
    Applicant: DENSO CORPORATION
    Inventors: Norihito TOKURA, Shigeki Takahashi, Youichi Ashida, Akio Nakagawa
  • Publication number: 20120032313
    Abstract: A semiconductor device having a lateral diode includes a semiconductor layer, a first semiconductor region in the semiconductor layer, a contact region having an impurity concentration greater than that of the first semiconductor region, a second semiconductor region located in the semiconductor layer and separated from the contact region, a first electrode electrically connected through the contact region to the first semiconductor region, and a second electrode electrically connected to the second semiconductor region. The second semiconductor region includes a low impurity concentration portion, a high impurity concentration portion, and an extension portion. The second electrode forms an ohmic contact with the high impurity concentration portion. The extension portion has an impurity concentration greater than that of the low impurity concentration portion and extends in a thickness direction of the semiconductor layer.
    Type: Application
    Filed: August 3, 2011
    Publication date: February 9, 2012
    Applicant: DENSO CORPORATION
    Inventors: Takao YAMAMOTO, Norihito Tokura, Hisato Kato, Akio Nakagawa