Patents by Inventor Futoshi Tokunoh

Futoshi Tokunoh 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: 7221047
    Abstract: A gate electrode (1a) is formed on the outer peripheral step portion (1?) of a semiconductor substrate (1) so as to face a pressure-contact supporting block (6), and a convex contacting portion (1g) is formed on a predetermined position on the surface of the gate electrode to contact the pressure contact supporting block. The surface area of the gate electrode ranging from the inner periphery to a position adjacent to the convex contacting portion, is coated with an insulation film (1d). The convex contacting portion (1g) is formed of a convex portion integral with the gate electrode or formed of another gate electrode (1a?).
    Type: Grant
    Filed: October 4, 2005
    Date of Patent: May 22, 2007
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Kenji Oota, Futoshi Tokunoh
  • Publication number: 20060027910
    Abstract: A gate electrode (1a) is formed on the outer peripheral step portion (1?) of a semiconductor substrate (1) so as to face a pressure-contact supporting block (6), and a convex contacting portion (1g) is formed on a predetermined position on the surface of the gate electrode to contact the pressure contact supporting block. The surface area of the gate electrode ranging from the inner periphery to a position adjacent to the convex contacting portion, is coated with an insulation film (1d). The convex contacting portion (1g) is formed of a convex portion integral with the gate electrode or formed of another gate electrode (1a?).
    Type: Application
    Filed: October 4, 2005
    Publication date: February 9, 2006
    Applicant: MITSUBISHI DENKI KABUSHIKI KAISHA
    Inventors: Kenji Oota, Futoshi Tokunoh
  • Patent number: 6995464
    Abstract: A gate electrode (1a) is formed on the outer peripheral step portion (1?) of a semiconductor substrate (1) so as to face a pressure-contact supporting block (6), and a convex contacting portion (1g) is formed on a predetermined position on the surface of the gate electrode to contact the pressure contact supporting block. The surface area of the gate electrode ranging from the inner periphery to a position adjacent to the convex contacting portion, is coated with an insulation film (1d). The convex contacting portion (1g) is formed of a convex portion integral with the gate electrode or formed of another gate electrode (1a?).
    Type: Grant
    Filed: January 28, 2004
    Date of Patent: February 7, 2006
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Kenji Oota, Futoshi Tokunoh
  • Publication number: 20040183093
    Abstract: A gate electrode (1a) is formed on the outer peripheral step portion (1′) of a semiconductor substrate (1) so as to face a pressure-contact supporting block (6), and a convex contacting portion (1g) is formed on a predetermined position on the surface of the gate electrode to contact the pressure contact supporting block. The surface area of the gate electrode ranging from the inner periphery to a position adjacent to the convex contacting portion, is coated with an insulation film (1d). The convex contacting portion (1g) is formed of a convex portion integral with the gate electrode or formed of another gate electrode (1a′).
    Type: Application
    Filed: January 28, 2004
    Publication date: September 23, 2004
    Applicant: MITSUBISHI DENKI KABUSHIKI KAISHA
    Inventors: Kenji Oota, Futoshi Tokunoh
  • Patent number: 6465881
    Abstract: A compression bonded type semiconductor device including a semiconductor substrate having a gate electrode and a cathode electrode formed on a first surface and an anode electrode formed on a second surface opposite to the first surface, an external cathode electrode disposed so as to be compression bondable to the cathode electrode, and an external anode electrode disposed so as to be compression bondable the anode electrode. Also included is an insulating cylinder containing the semiconductor substrate, an external gate terminal having an outer peripheral portion protruding to an outside of the insulating cylinder and having a protrusion at an inner peripheral portion configured to about said gate electrode, and an elastic body configured to press the protrusion of the external gate terminal to the gate electrode.
    Type: Grant
    Filed: September 18, 2000
    Date of Patent: October 15, 2002
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Futoshi Tokunoh
  • Patent number: 6020603
    Abstract: A high voltage semiconductor device such as a gate turn-off thyristor, reduces surface field concentration of a main P-N junction part and attains withstand voltage increase.
    Type: Grant
    Filed: May 22, 1998
    Date of Patent: February 1, 2000
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Futoshi Tokunoh, Yasuo Tanaka, Tokumitsu Sakamoto, Nobuhisa Nakasima
  • Patent number: 5640024
    Abstract: A compression-type semiconductor device comprises a silicon substrate in which crystal orientation between main faces opposite to each other is not larger than <1,0,0> .+-.27.5.degree.; cathode and gate electrodes formed on one of the main faces of the silicon substrate; an anode electrode formed on the other of the main faces of the silicon substrate; a cathode thermal compensation plate for the cathode and gate electrodes; and an anode thermal compensation plate for the anode electrode.
    Type: Grant
    Filed: December 8, 1995
    Date of Patent: June 17, 1997
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Kazuhiro Morishita, Kazuhisa Ide, Futoshi Tokunoh
  • Patent number: 5574297
    Abstract: In order to compatibly implement improvement in withstand voltage and ON-state resistance as well as reduction in turnon loss and improvement in di/dt resistance, an n buffer layer (12) is locally exposed on a lower surface of a semiconductor substrate (160), while a polysilicon additional resistive layer (104) is formed to cover the exposed surface. An anode electrode (101) covering the lower surface of the semiconductor substrate (160) is connected to a p emitter layer (11) and the additional resistive layer (104). Thus, the n buffer layer (12) and the anode electrode (101) are connected with each other through the additional resistive layer (104), whereby a gate trigger current is reduced. Thus, turnon loss is reduced and di/dt resistance is increased. At the same time, the withstand voltage and the ON-state resistance are excellent due to provision of the n buffer layer (12).
    Type: Grant
    Filed: March 21, 1995
    Date of Patent: November 12, 1996
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Nozomu Sennenbara, Kouji Niinobu, Kazuhiko Niwayama, Futoshi Tokunoh
  • Patent number: 5543363
    Abstract: In a semiconductor device, a semiconductor element is stored in a casing while being held by external electrodes through first and second electrodes. The outer peripheral edge of the first electrode plate is projected outwardly beyond that of the semiconductor element and a ring-shaped groove is provided in the first surface of the first electrode plate along the outer peripheral edge of the semiconductor element such that a line, which is projected along the outer peripheral edge of the semiconductor element on the first surface of the first electrode plate, is located on the ring-shaped groove portion. The adhesive holding member is applied in the groove and the outer peripheral portion of the semiconductor element. Thus, the semiconductor element is fixed to the first electrode plate and is protected by the adhesive holding member which covers its end portion.
    Type: Grant
    Filed: August 16, 1994
    Date of Patent: August 6, 1996
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Futoshi Tokunoh, Katsumi Satoh
  • Patent number: 5428230
    Abstract: A reverse conducting gate turn-off thyristor (RC-GTO) includes, in the same semiconductor body, a gate turn-off thyristor, a reverse current diode, and a semiconductor isolation region between the gate turn-off thyristor and the reverse current diode and having a first conductivity type semiconductor layer adjacent an anode electrode and spaced apart second conductivity type high-dopant-impurity-concentration regions opposite the anode electrode.
    Type: Grant
    Filed: March 24, 1994
    Date of Patent: June 27, 1995
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Kazuhiro Morishita, Futoshi Tokunoh
  • Patent number: 5393995
    Abstract: There is disclosed a semiconductor device wherein a p layer (7) is formed in an isolating portion (Z) and portions (1a, 1b) of an n-type base layer (1) lie on opposite sides of the p layer (7), the upper surfaces of the p layer (7) and the portions (1a, 1b) lying in the same plane as the upper surface of a p layer (3). The presence of the p layer (7) provides for high resistance to breakdown and high formation accuracy of the p layers (2, 3, 7) as compared with a structure in which the isolating portion (Z) lies in the bottom of a the recess, whereby the semiconductor device is less susceptible to short-circuit between the p-type base layer (2) and the p layer (3).
    Type: Grant
    Filed: May 28, 1993
    Date of Patent: February 28, 1995
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tsutomu Nakagawa, Futoshi Tokunoh, Kouji Niinobu
  • Patent number: 5371386
    Abstract: In a semiconductor device, a semiconductor element is stored in a casing while being held by external electrodes through first and second electrodes. The outer peripheral edge of the first electrode plate is projected outwardly beyond that of the semiconductor element and a ring-shaped groove is provided in the first surface of the first electrode plate along the outer peripheral edge of the semiconductor element. An adhesive holding member is charged in the groove and the outer peripheral portion of the semiconductor element. Thus, the semiconductor element is fixed to the first electrode plate and is protected by the adhesive holding member covering its end portion.
    Type: Grant
    Filed: April 15, 1993
    Date of Patent: December 6, 1994
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Futoshi Tokunoh, Katsumi Satoh
  • Patent number: 5346849
    Abstract: A semiconductor structure comprises a gate-turn-off thyristor region (GR) and a diode region (DR) with an isolation area (SR) therebetween. The isolation area is provided with a multistage groove (30) having step structures (34,35). The multistage groove is formed through a two-stage etching process, and over-etched regions in the bottom corners of the multistage groove are relatively shallow ones. This structure is effective for increasing the breakdown voltage of the semiconductor structure and isolations between the gate-turn-off thyristor region and the diode region.
    Type: Grant
    Filed: September 9, 1993
    Date of Patent: September 13, 1994
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Futoshi Tokunoh
  • Patent number: 5281847
    Abstract: A semiconductor structure comprises a gate-turn-off thyristor region (GR) and a diode region (DR) with an isolation area (SR) therebetween. The isolation area is provided with a multistage groove (30) having step structures (34,35). The multistage groove is formed through a two-stage etching process, and over-etched regions in the bottom corners of the multistage groove are relatively shallow ones. This structure is effective for increasing the breakdown voltage of the semiconductor structure and isolations between a the gate-turnoff thyristor region and the diode region.
    Type: Grant
    Filed: January 25, 1993
    Date of Patent: January 25, 1994
    Assignee: Mitsubishi Denki Kabushik Kaisha
    Inventor: Futoshi Tokunoh
  • Patent number: 5189509
    Abstract: A flat-pack type GTO thyristor (100) has an external cathode electrode (30) placed on a semiconductor element (1). The top surface of the external cathode electrode has a three-level step configuration (33a, 33b, 33c). When a cathode member (51) of an external electric equipment is pushed onto the external cathode electrode, no force is applied to the lower two steps (33b, 33c) in the step configuration. Consequently, the peripheral portion of the external cathode electrode is not deformed and the semiconductor element does not become unstable in gate characteristics.
    Type: Grant
    Filed: December 4, 1990
    Date of Patent: February 23, 1993
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Katsumi Satoh, Futoshi Tokunoh
  • Patent number: 5082800
    Abstract: A method of manufacturing a semiconductor device including a semiconductor substrate (10) comprising n-emitter regions (14a-14c) formed before the substrate is brazed on a molybdenum plate (1). Due to the difference between respective thermal expansion coefficients of silicon and molybdenum, the substrate is warped through the brazing process and the horizontal positions of the n-emitter regions are shifted. A mask pattern for patterning an aluminum layer (31) is corrected in position to prevent a patterned aluminum layer from extending over the peripheral areas of the n-emitter regions.
    Type: Grant
    Filed: February 12, 1991
    Date of Patent: January 21, 1992
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Koji Niinobu, Futoshi Tokunoh
  • Patent number: 5047836
    Abstract: According to the present invention, one surface of a temperature compensator is arranged to face the surface of a first electrode which is formed on one surface of a semiconductor element while one surface of a first external electrode is arranged to face the other surface of the temperature compensator. A second external electrode is arranged in a space region which is defined by a through hole of the temperature compensator and a cavity of the first external electrode, to face the surface of a second electrode. An insulator is interposed between the outer side surface of the second external electrode and the inner side surfaces of the cavity and the through hole so that the second external electrode is located in prescribed positional relation to the first external electrode and the temperature compensator.
    Type: Grant
    Filed: October 2, 1990
    Date of Patent: September 10, 1991
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Futoshi Tokunoh
  • Patent number: 5047824
    Abstract: A reverse conducting gate turn-off thyristor has a separating layer (26) in isolating zone (Z) for electrically separating into thyristor and diode portion (X, Z) a p type base layer (22) formed on an n type base layer (21). A gate electrode (29) is formed both on the p type base layer (22) and the separating layer. A portion of the gate electrode (29) on said separating layer serves as a gate collecting electrode (29a). Thus, area for the isolating zone (Z) and the gate collecting electrode (29a) become common, so that the efficiency of utilization of the wafer surface can be increased.
    Type: Grant
    Filed: April 27, 1989
    Date of Patent: September 10, 1991
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Futoshi Tokunoh, Katsumi Sato
  • Patent number: 4881118
    Abstract: One surface of a cathode sliding compensator is finished as an irregular surface while another surface thereof is finished as a sliding surface. The irregular surface is arranged to contact with a cathode electrode layer of a semiconductor element while the sliding surface is arranged to contact with a cathode conductor, and junction surfaces therebetween are electrically and mechanically connected by pressurization. Thus, the irregular surface bites into the cathode electrode layer to attain excellent electrical and mechanical connection between the cathode electrode layer and the cathode sliding compensator, while slidingness can be effectively retained between the cathode conductor and the cathode sliding compensator by the function of the sliding surface.
    Type: Grant
    Filed: April 28, 1989
    Date of Patent: November 14, 1989
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Kazuhiko Niwayama, Tsutomu Nakagawa, Futoshi Tokunoh, Shigekazu Yoshida
  • Patent number: 4835119
    Abstract: A semiconductor device which comprises: a first main electrode on a first main surface of the semiconductor substrate, and a second main electrode on a second main surface thereof, the first main surface including a control electrode; a first outer main electrode and a second outer main electrode provided on the first and second main surface, respectively, wherein the first and second outer main electrodes are respectively connected to the first main electrode and the second main electrode; an external control electrode adapted for connection to the control electrode on the semiconductor substrate; a control electrode access electrode whereby the control electrode on the substrate is connected to the external control electrode; the control electrode access electrode including a ring-shaped body having a contact section on the undersurface thereof, and a lead for connection to the external control electrode, wherein the ring-shaped body is covered with an insulating film in the portion excluding the contact se
    Type: Grant
    Filed: September 30, 1987
    Date of Patent: May 30, 1989
    Assignee: Mitsubishi Kenki Kabushiki Kaisha
    Inventor: Futoshi Tokunoh