Patents by Inventor Katsuhisa Nagao

Katsuhisa Nagao 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: 11908868
    Abstract: A semiconductor device (1) is manufactured which includes a SiC epitaxial layer (28), a plurality of transistor cells (18) that are formed in the SiC epitaxial layer (28) and that are subjected to ON/OFF control by a predetermined control voltage, a gate electrode (19) that faces a channel region (32) of the transistor cells (18) in which a channel is formed when the semiconductor device (1) is in an ON state, a gate metal (44) that is exposed at the topmost surface for electrical connection with the outside and that is electrically connected to the gate electrode (19) while being physically separated from the gate electrode (19), and a built-in resistor (21) that is made of polysilicon and that is disposed below the gate metal (44) so as to electrically connect the gate metal (44) and the gate electrode (19) together.
    Type: Grant
    Filed: May 19, 2022
    Date of Patent: February 20, 2024
    Assignee: ROHM CO., LTD.
    Inventors: Katsuhisa Nagao, Noriaki Kawamoto
  • Publication number: 20240014081
    Abstract: A semiconductor structure for inspection includes a semiconductor plate having a first main surface on one side and a second main surface on the other side, an inspection region provided in the first main surface, a main surface electrode having a first hardness and covering the first main surface in the inspection region, and a protective electrode having a second hardness which exceeds the first hardness, covering the main surface electrode in the inspection region, and forming a current path between the second main surface and the protective electrode via the semiconductor plate.
    Type: Application
    Filed: September 26, 2023
    Publication date: January 11, 2024
    Applicant: ROHM CO., LTD.
    Inventors: Toshiro TAKAO, Katsuhisa NAGAO, Yoshiro ENOKIDA
  • Patent number: 11862672
    Abstract: [Object] To provide a semiconductor device capable of improving a discharge starting voltage when measuring electric characteristics, and widening a pad area of a surface electrode or increasing the number of semiconductor devices (number of chips) to be obtained from one wafer, and a method for manufacturing the same. [Solution Means] A semiconductor device 1 includes an n-type SiC layer 2 having a first surface 2A, a second surface 2B, and end faces 2C, a p-type voltage relaxing layer 7 formed in the SiC layer 2 so as to be exposed to the end portion of the first surface 2A of the SiC layer 2, an insulating layer 8 formed on the SiC layer 2 so as to cover the voltage relaxing layer 7, and an anode electrode 9 that is connected to the first surface 2A of the SiC layer 2 through the insulating layer 8 and has a pad area 95 selectively exposed.
    Type: Grant
    Filed: June 22, 2021
    Date of Patent: January 2, 2024
    Assignee: ROHM CO., LTD.
    Inventor: Katsuhisa Nagao
  • Publication number: 20230273245
    Abstract: A SiC semiconductor device is provided that is capable of improving the detection accuracy of the current value of a principal current detected by a current sensing portion by restraining heat from escaping from the current sensing portion to a wiring member joined to a sensing-side surface electrode. The semiconductor device 1 includes a SiC semiconductor substrate, a source portion 27 including a principal-current-side unit cell 34, a current sensing portion 26 including a sensing-side unit cell 40, a source-side surface electrode 5 disposed above the source portion 27, and a sensing-side surface electrode 6 that is disposed above the current sensing portion 26 and that has a sensing-side pad 15 to which a sensing-side wire is joined, and, in the semiconductor device 1, the sensing-side unit cell 40 is disposed so as to avoid being positioned directly under the sensing-side pad 15.
    Type: Application
    Filed: May 3, 2023
    Publication date: August 31, 2023
    Inventor: Katsuhisa NAGAO
  • Patent number: 11674983
    Abstract: A SiC semiconductor device is provided that is capable of improving the detection accuracy of the current value of a principal current detected by a current sensing portion by restraining heat from escaping from the current sensing portion to a wiring member joined to a sensing-side surface electrode. The semiconductor device 1 includes a SiC semiconductor substrate, a source portion 27 including a principal-current-side unit cell 34, a current sensing portion 26 including a sensing-side unit cell 40, a source-side surface electrode 5 disposed above the source portion 27, and a sensing-side surface electrode 6 that is disposed above the current sensing portion 26 and that has a sensing-side pad 15 to which a sensing-side wire is joined, and, in the semiconductor device 1, the sensing-side unit cell 40 is disposed so as to avoid being positioned directly under the sensing-side pad 15.
    Type: Grant
    Filed: November 29, 2021
    Date of Patent: June 13, 2023
    Assignee: ROHM CO., LTD.
    Inventor: Katsuhisa Nagao
  • Publication number: 20220406887
    Abstract: [Object] To provide a semiconductor device capable of improving a discharge starting voltage when measuring electric characteristics, and widening a pad area of a surface electrode or increasing the number of semiconductor devices (number of chips) to be obtained from one wafer, and a method for manufacturing the same. [Solution Means] A semiconductor device 1 includes an n-type SiC layer 2 having a first surface 2A, a second surface 2B, and end faces 2C, a p-type voltage relaxing layer 7 formed in the SiC layer 2 so as to be exposed to the end portion of the first surface 2A of the SiC layer 2, an insulating layer 8 formed on the SiC layer 2 so as to cover the voltage relaxing layer 7, and an anode electrode 9 that is connected to the first surface 2A of the SiC layer 2 through the insulating layer 8 and has a pad area 95 selectively exposed.
    Type: Application
    Filed: August 5, 2022
    Publication date: December 22, 2022
    Inventor: Katsuhisa NAGAO
  • Publication number: 20220278133
    Abstract: A semiconductor device (1) is manufactured which includes a SiC epitaxial layer (28), a plurality of transistor cells (18) that are formed in the SiC epitaxial layer (28) and that are subjected to ON/OFF control by a predetermined control voltage, a gate electrode (19) that faces a channel region (32) of the transistor cells (18) in which a channel is formed when the semiconductor device (1) is in an ON state, a gate metal (44) that is exposed at the topmost surface for electrical connection with the outside and that is electrically connected to the gate electrode (19) while being physically separated from the gate electrode (19), and a built-in resistor (21) that is made of polysilicon and that is disposed below the gate metal (44) so as to electrically connect the gate metal (44) and the gate electrode (19) together.
    Type: Application
    Filed: May 19, 2022
    Publication date: September 1, 2022
    Inventors: Katsuhisa NAGAO, Noriaki KAWAMOTO
  • Publication number: 20220262912
    Abstract: A semiconductor device includes a semiconductor region made of a material to which conductive impurities are added, an insulating film formed on a surface of the semiconductor region, and an electroconductive gate electrode formed on the insulating film. The gate electrode is made of a material whose Fermi level is closer to a Fermi level of the semiconductor region than a Fermi level of Si in at least a portion contiguous to the insulating film.
    Type: Application
    Filed: May 9, 2022
    Publication date: August 18, 2022
    Inventors: Yuki NAKANO, Ryota NAKAMURA, Katsuhisa NAGAO
  • Patent number: 11367738
    Abstract: A semiconductor device (1) is manufactured which includes a SiC epitaxial layer (28), a plurality of transistor cells (18) that are formed in the SiC epitaxial layer (28) and that are subjected to ON/OFF control by a predetermined control voltage, a gate electrode (19) that faces a channel region (32) of the transistor cells (18) in which a channel is formed when the semiconductor device (1) is in an ON state, a gate metal (44) that is exposed at the topmost surface for electrical connection with the outside and that is electrically connected to the gate electrode (19) while being physically separated from the gate electrode (19), and a built-in resistor (21) that is made of polysilicon and that is disposed below the gate metal (44) so as to electrically connect the gate metal (44) and the gate electrode (19) together.
    Type: Grant
    Filed: December 2, 2020
    Date of Patent: June 21, 2022
    Assignee: ROHM CO., LTD.
    Inventors: Katsuhisa Nagao, Noriaki Kawamoto
  • Patent number: 11355609
    Abstract: A semiconductor device includes a semiconductor region made of a material to which conductive impurities are added, an insulating film formed on a surface of the semiconductor region, and an electroconductive gate electrode formed on the insulating film. The gate electrode is made of a material whose Fermi level is closer to a Fermi level of the semiconductor region than a Fermi level of Si in at least a portion contiguous to the insulating film.
    Type: Grant
    Filed: September 10, 2020
    Date of Patent: June 7, 2022
    Assignee: ROHM CO., LTD.
    Inventors: Yuki Nakano, Ryota Nakamura, Katsuhisa Nagao
  • Publication number: 20220082593
    Abstract: A SiC semiconductor device is provided that is capable of improving the detection accuracy of the current value of a principal current detected by a current sensing portion by restraining heat from escaping from the current sensing portion to a wiring member joined to a sensing-side surface electrode. The semiconductor device 1 includes a SiC semiconductor substrate, a source portion 27 including a principal-current-side unit cell 34, a current sensing portion 26 including a sensing-side unit cell 40, a source-side surface electrode 5 disposed above the source portion 27, and a sensing-side surface electrode 6 that is disposed above the current sensing portion 26 and that has a sensing-side pad 15 to which a sensing-side wire is joined, and, in the semiconductor device 1, the sensing-side unit cell 40 is disposed so as to avoid being positioned directly under the sensing-side pad 15.
    Type: Application
    Filed: November 29, 2021
    Publication date: March 17, 2022
    Inventor: Katsuhisa NAGAO
  • Patent number: 11215647
    Abstract: A SiC semiconductor device is provided that is capable of improving the detection accuracy of the current value of a principal current detected by a current sensing portion by restraining heat from escaping from the current sensing portion to a wiring member joined to a sensing-side surface electrode. The semiconductor device 1 includes a SiC semiconductor substrate, a source portion 27 including a principal-current-side unit cell 34, a current sensing portion 26 including a sensing-side unit cell 40, a source-side surface electrode 5 disposed above the source portion 27, and a sensing-side surface electrode 6 that is disposed above the current sensing portion 26 and that has a sensing-side pad 15 to which a sensing-side wire is joined, and, in the semiconductor device 1, the sensing-side unit cell 40 is disposed so as to avoid being positioned directly under the sensing-side pad 15.
    Type: Grant
    Filed: June 3, 2020
    Date of Patent: January 4, 2022
    Assignee: ROHM CO., LTD.
    Inventor: Katsuhisa Nagao
  • Publication number: 20210313418
    Abstract: [Object] To provide a semiconductor device capable of improving a discharge starting voltage when measuring electric characteristics, and widening a pad area of a surface electrode or increasing the number of semiconductor devices (number of chips) to be obtained from one wafer, and a method for manufacturing the same. [Solution Means] A semiconductor device 1 includes an n-type SiC layer 2 having a first surface 2A, a second surface 2B, and end faces 2C, a p-type voltage relaxing layer 7 formed in the SiC layer 2 so as to be exposed to the end portion of the first surface 2A of the SiC layer 2, an insulating layer 8 formed on the SiC layer 2 so as to cover the voltage relaxing layer 7, and an anode electrode 9 that is connected to the first surface 2A of the SiC layer 2 through the insulating layer 8 and has a pad area 95 selectively exposed.
    Type: Application
    Filed: June 22, 2021
    Publication date: October 7, 2021
    Inventor: Katsuhisa NAGAO
  • Patent number: 11075263
    Abstract: [Object] To provide a semiconductor device capable of improving a discharge starting voltage when measuring electric characteristics, and widening a pad area of a surface electrode or increasing the number of semiconductor devices (number of chips) to be obtained from one wafer, and a method for manufacturing the same. [Solution Means] A semiconductor device 1 includes an n-type SiC layer 2 having a first surface 2A, a second surface 2B, and end faces 2C, a p-type voltage relaxing layer 7 formed in the SiC layer 2 so as to be exposed to the end portion of the first surface 2A of the SiC layer 2, an insulating layer 8 formed on the SiC layer 2 so as to cover the voltage relaxing layer 7, and an anode electrode 9 that is connected to the first surface 2A of the SiC layer 2 through the insulating layer 8 and has a pad area 95 selectively exposed.
    Type: Grant
    Filed: January 8, 2019
    Date of Patent: July 27, 2021
    Assignee: ROHM CO, , LTD.
    Inventor: Katsuhisa Nagao
  • Publication number: 20210091117
    Abstract: A semiconductor device (1) is manufactured which includes a SiC epitaxial layer (28), a plurality of transistor cells (18) that are formed in the SiC epitaxial layer (28) and that are subjected to ON/OFF control by a predetermined control voltage, a gate electrode (19) that faces a channel region (32) of the transistor cells (18) in which a channel is formed when the semiconductor device (1) is in an ON state, a gate metal (44) that is exposed at the topmost surface for electrical connection with the outside and that is electrically connected to the gate electrode (19) while being physically separated from the gate electrode (19), and a built-in resistor (21) that is made of polysilicon and that is disposed below the gate metal (44) so as to electrically connect the gate metal (44) and the gate electrode (19) together.
    Type: Application
    Filed: December 2, 2020
    Publication date: March 25, 2021
    Inventors: Katsuhisa NAGAO, Noriaki KAWAMOTO
  • Patent number: 10886300
    Abstract: A semiconductor device (1) is manufactured which includes a SiC epitaxial layer (28), a plurality of transistor cells (18) that are formed in the SiC epitaxial layer (28) and that are subjected to ON/OFF control by a predetermined control voltage, a gate electrode (19) that faces a channel region (32) of the transistor cells (18) in which a channel is formed when the semiconductor device (1) is in an ON state, a gate metal (44) that is exposed at the topmost surface for electrical connection with the outside and that is electrically connected to the gate electrode (19) while being physically separated from the gate electrode (19), and a built-in resistor (21) that is made of polysilicon and that is disposed below the gate metal (44) so as to electrically connect the gate metal (44) and the gate electrode (19) together.
    Type: Grant
    Filed: August 29, 2019
    Date of Patent: January 5, 2021
    Assignee: ROHM CO., LTD.
    Inventors: Katsuhisa Nagao, Noriaki Kawamoto
  • Publication number: 20200411655
    Abstract: A semiconductor device includes a semiconductor region made of a material to which conductive impurities are added, an insulating film formed on a surface of the semiconductor region, and an electroconductive gate electrode formed on the insulating film. The gate electrode is made of a material whose Fermi level is closer to a Fermi level of the semiconductor region than a Fermi level of Si in at least a portion contiguous to the insulating film.
    Type: Application
    Filed: September 10, 2020
    Publication date: December 31, 2020
    Inventors: Yuki NAKANO, Ryota NAKAMURA, Katsuhisa NAGAO
  • Patent number: 10797145
    Abstract: A semiconductor device includes a semiconductor region made of a material to which conductive impurities are added, an insulating film formed on a surface of the semiconductor region, and an electroconductive gate electrode formed on the insulating film. The gate electrode is made of a material whose Fermi level is closer to a Fermi level of the semiconductor region than a Fermi level of Si in at least a portion contiguous to the insulating film.
    Type: Grant
    Filed: October 2, 2019
    Date of Patent: October 6, 2020
    Assignee: ROHM CO., LTD.
    Inventors: Yuki Nakano, Ryota Nakamura, Katsuhisa Nagao
  • Publication number: 20200292590
    Abstract: A SiC semiconductor device is provided that is capable of improving the detection accuracy of the current value of a principal current detected by a current sensing portion by restraining heat from escaping from the current sensing portion to a wiring member joined to a sensing-side surface electrode. The semiconductor device 1 includes a SiC semiconductor substrate, a source portion 27 including a principal-current-side unit cell 34, a current sensing portion 26 including a sensing-side unit cell 40, a source-side surface electrode 5 disposed above the source portion 27, and a sensing-side surface electrode 6 that is disposed above the current sensing portion 26 and that has a sensing-side pad 15 to which a sensing-side wire is joined, and, in the semiconductor device 1, the sensing-side unit cell 40 is disposed so as to avoid being positioned directly under the sensing-side pad 15.
    Type: Application
    Filed: June 3, 2020
    Publication date: September 17, 2020
    Inventor: Katsuhisa NAGAO
  • Publication number: 20200279923
    Abstract: According to the present invention, a semiconductor device includes a first conductivity type SiC layer, an electrode that is selectively formed upon the SiC layer, and an insulator that is formed upon the SiC layer and that extends to a timing region that is set at an end part of the SiC layer. The insulator includes an electrode lower insulating film that is arranged below the electrode, and an organic insulating layer that is arranged so as to cover the electrode lower insulating film. The length (A) of the interval wherein the organic insulating layer contacts the SiC layer is 40 ?m or more, and the lateral direction distance (B) along the electrode lower insulating layer between the electrode and SiC layer is 40 ?m or more.
    Type: Application
    Filed: May 19, 2020
    Publication date: September 3, 2020
    Inventors: Katsuhisa NAGAO, Hidetoshi ABE