Patents by Inventor Masana Harada

Masana Harada 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: 7253031
    Abstract: A pin diode is formed by a p+ collector region, an n type buffer region, an n? region and an n+ cathode region. A trench is formed from the surface of n+ cathode region through n+ cathode region to reach n? region. An insulating film is formed along an inner wall surface of trench. A gate electrode layer is formed to oppose to the sidewall of n+ cathode region with insulating film interposed. A cathode electrode is formed to be electrically connected to n+ cathode region. An anode electrode is formed to be electrically connected to p+ collector region. The n+ cathode region is formed entirely over the surface between trenches extending parallel to each other. Thus, a power semiconductor device in which gate control circuit is simplified and which has good on property can be obtained.
    Type: Grant
    Filed: November 2, 2004
    Date of Patent: August 7, 2007
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tetsuo Takahashi, Katsumi Nakamura, Tadaharu Minato, Masana Harada
  • Patent number: 6979874
    Abstract: A plurality of p anode regions are formed at one surface of an n? substrate. A trench is formed in each p anode region. An ohmic junction region is formed between an anode metallic electrode and the p anode region. The p anode region has a minimum impurity concentration at a portion near the ohmic junction region which enables ohmic contact. A cathode metallic electrode is formed at the other surface of the n? substrate with an n+ cathode region interposed. Accordingly, a semiconductor device which has an improved withstand voltage and in which the reverse recovery current is reduced can be obtained.
    Type: Grant
    Filed: October 30, 2002
    Date of Patent: December 27, 2005
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Masana Harada
  • Patent number: 6897493
    Abstract: A pin diode is formed by a p+ collector region, an n type buffer region, an n? region and an n+ cathode region. A trench is formed from the surface of n+ cathode region through n+ cathode region to reach n? region. An insulating film is formed along an inner wall surface of trench. A gate electrode layer is formed to oppose to the sidewall of n+ cathode region with insulating film interposed. A cathode electrode is formed to be electrically connected to n+ cathode region. An anode electrode is formed to be electrically connected to p+ collector region. The n+ cathode region is formed entirely over the surface between trenches extending parallel to each other. Thus, a power semiconductor device in which gate control circuit is simplified and which has good on property can be obtained.
    Type: Grant
    Filed: June 10, 2003
    Date of Patent: May 24, 2005
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tetsuo Takahashi, Katsumi Nakamura, Tadaharu Minato, Masana Harada
  • Publication number: 20050062073
    Abstract: A pin diode is formed by a p+ collector region, an n type buffer region, an n? region and an n+ cathode region. A trench is formed from the surface of n+ cathode region through n+ cathode region to reach n? region. An insulating film is formed along an inner wall surface of trench. A gate electrode layer is formed to oppose to the sidewall of n+ cathode region with insulating film interposed. A cathode electrode is formed to be electrically connected to n+ cathode region. An anode electrode is formed to be electrically connected to p+ collector region. The n+ cathode region is formed entirely over the surface between trenches extending parallel to each other. Thus, a power semiconductor device in which gate control circuit is simplified and which has good on property can be obtained.
    Type: Application
    Filed: November 2, 2004
    Publication date: March 24, 2005
    Applicant: MITSUBISHI DENKI KABUSHIKI KAISHA
    Inventors: Tetsuo Takahashi, Katsumi Nakamura, Tadaharu Minato, Masana Harada
  • Patent number: 6867437
    Abstract: A pin diode is formed by a p+ collector region, an n type buffer region, an n? region and an n+ cathode region. A trench is formed from the surface of n+ cathode region through n+ cathode region to reach n? region. An insulating film is formed along an inner wall surface of trench. A gate electrode layer is formed to oppose to the sidewall of n+ cathode region with insulating film interposed. A cathode electrode is formed to be electrically connected to n+ cathode region. An anode electrode is formed to be electrically connected to p+ collector region. The n+ cathode region is formed entirely over the surface between trenches extending parallel to each other. Thus, a power semiconductor device in which gate control circuit is simplified and which has good on property can be obtained.
    Type: Grant
    Filed: August 20, 2002
    Date of Patent: March 15, 2005
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tetsuo Takahashi, Katsumi Nakamura, Tadaharu Minato, Masana Harada
  • Patent number: 6693310
    Abstract: A pin diode is formed by a p+ collector region, an n type buffer region, an n− region and an n+ cathode region. A trench is formed from the surface of n+ cathode region through n+ cathode region to reach n− region. An insulating film is formed along an inner wall surface of trench. A gate electrode layer is formed to oppose to the sidewall of n+ cathode region with insulating film interposed. A cathode electrode is formed to be electrically connected to n+ cathode region. An anode electrode is formed to be electrically connected to p+ collector region. The n+ cathode region is formed entirely over the surface between trenches extending parallel to each other. Thus, a power semiconductor device in which gate control circuit is simplified and which has good on property can be obtained.
    Type: Grant
    Filed: May 23, 2001
    Date of Patent: February 17, 2004
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tetsuo Takahashi, Katsumi Nakamura, Tadaharu Minato, Masana Harada
  • Publication number: 20030201455
    Abstract: A pin diode is formed by a p+ collector region, an n type buffer region, an n− region and an n+ cathode region. A trench is formed from the surface of n+ cathode region through n+ cathode region to reach n− region. An insulating film is formed along an inner wall surface of trench. A gate electrode layer is formed to oppose to the sidewall of n+ cathode region with insulating film interposed. A cathode electrode is formed to be electrically connected to n+ cathode region. An anode electrode is formed to be electrically connected to p+ collector region. The n+ cathode region is formed entirely over the surface between trenches extending parallel to each other. Thus, a power semiconductor device in which gate control circuit is simplified and which has good on property can be obtained.
    Type: Application
    Filed: June 10, 2003
    Publication date: October 30, 2003
    Applicant: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tetsuo Takahashi, Katsumi Nakamura, Tadaharu Minato, Masana Harada
  • Publication number: 20030057482
    Abstract: A plurality of p anode regions are formed at one surface of an n− substrate. A trench is formed in each p anode region. An ohmic junction region is formed between an anode metallic electrode and the p anode region. The p anode region has a minimum impurity concentration at a portion near the ohmic junction region which enables ohmic contact. A cathode metallic electrode is formed at the other surface of the n− substrate with an n+ cathode region interposed. Accordingly, a semiconductor device which has an improved withstand voltage and in which the reverse recovery current is reduced can be obtained.
    Type: Application
    Filed: October 30, 2002
    Publication date: March 27, 2003
    Inventor: Masana Harada
  • Publication number: 20030006456
    Abstract: A pin diode is formed by a p+ collector region, an n type buffer region, an n− region and an n+ cathode region. A trench is formed from the surface of n+ cathode region through n+ cathode region to reach n− region. An insulating film is formed along an inner wall surface of trench. A gate electrode layer is formed to oppose to the sidewall of n+ cathode region with insulating film interposed. A cathode electrode is formed to be electrically connected to n+ cathode region. An anode electrode is formed to be electrically connected to p+ collector region. The n+ cathode region is formed entirely over the surface between trenches extending parallel to each other. Thus, a power semiconductor device in which gate control circuit is simplified and which has good on property can be obtained.
    Type: Application
    Filed: August 20, 2002
    Publication date: January 9, 2003
    Applicant: MITSUBISHI DENKI KABUSHIKI KAISHA
    Inventors: Tetsuo Takahashi, Katsumi Nakamura, Tadaharu Minato, Masana Harada
  • Patent number: 6501146
    Abstract: A plurality of p anode regions are formed at one surface of an n− substrate. A trench is formed in each p anode region. An ohmic junction region is formed between an anode metallic electrode and the p anode region. The p anode region has a minimum impurity concentration at a portion near the ohmic junction region which enables ohmic contact. A cathode metallic electrode is formed at the other surface of the n− substrate with an n+ cathode region interposed. Accordingly, a semiconductor device which has an improved withstand voltage and in which the reverse recovery current is reduced can be obtained.
    Type: Grant
    Filed: December 10, 1997
    Date of Patent: December 31, 2002
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Masana Harada
  • Patent number: 6445012
    Abstract: A pin diode is formed by a p+ collector region, an n type buffer region, an n− region and an n+ cathode region. A trench is formed from the surface of n+ cathode region through n+ cathode region to reach n− region. An insulating film is formed along an inner wall surface of trench. A gate electrode layer is formed to oppose to the sidewall of n+ cathode region with insulating film interposed. A cathode electrode is formed to be electrically connected to n+ cathode region. An anode electrode is formed to be electrically connected to p+ collector region. The n+ cathode region is formed entirely over the surface between trenches extending parallel to each other. Thus, a power semiconductor device in which gate control circuit is simplified and which has good on property can be obtained.
    Type: Grant
    Filed: May 23, 2001
    Date of Patent: September 3, 2002
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tetsuo Takahashi, Katsumi Nakamura, Tadaharu Minato, Masana Harada
  • Patent number: 6331466
    Abstract: An insulated gate semiconductor device in which the ON voltage is decreased by providing strip like trenches (207) having gate electrodes (210) buried therein are formed in an upper main surface of a semiconductor base body (200), and an N+ emitter layer (206) is exposed in a ladder-like form in the upper main surface of the semiconductor base body interposed between adjacent trenches (207). Accordingly, even if the position of a zonal region (Ra) which is a contact surface with an emitter electrode (212) is shifted, the emitter electrode (212) is surely in contact with the N+ emitter layer (206). Furthermore, the ladder-like N+ emitter layer (206) is formed adjacent to the trench (207), so that a channel region (208) is formed without discontinuation along the trench (207). Accordingly, it has the effect of facilitating miniaturization of elements and of effectively making use of the miniaturization to decrease the ON voltage.
    Type: Grant
    Filed: May 2, 2000
    Date of Patent: December 18, 2001
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Hideki Takahashi, Hidenori Nishihara, Masana Harada, Tadaharu Minato
  • Publication number: 20010045566
    Abstract: A pin diode is formed by a p+ collector region, an n type buffer region, an n− region and an n+ cathode region. A trench is formed from the surface of n+ cathode region through n+ cathode region to reach n− region. An insulating film is formed along an inner wall surface of trench. A gate electrode layer is formed to oppose to the sidewall of n+ cathode region with insulating film interposed. A cathode electrode is formed to be electrically connected to n+ cathode region. An anode electrode is formed to be electrically connected to p+ collector region. The n+ cathode region is formed entirely over the surface between trenches extending parallel to each other. Thus, a power semiconductor device in which gate control circuit is simplified and which has good on property can be obtained.
    Type: Application
    Filed: May 23, 2001
    Publication date: November 29, 2001
    Applicant: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tetsuo Takahashi, Katsumi Nakamura, Tadaharu Minato, Masana Harada
  • Patent number: 6323508
    Abstract: An insulated gate semiconductor device in which the ON voltage is decreased by providing strip like trenches (207) having gate electrodes (210) buried therein are formed in an upper main surface of a semiconductor base body (200), and an N+ emitter layer (206) is exposed in a ladder-like form in the upper main surface of the semiconductor base body interposed between adjacent trenches (207). Accordingly, even if the position of a zonal region (Ra) which is a contact surface with an emitter electrode (212) is shifted, the emitter electrode (212) is surely in contact with the N+ emitter layer (206). Furthermore, the ladder-like N+ emitter layer (206) is formed adjacent to the trench (7), so that a channel region (208) is formed without discontinuation along the trench (207). Accordingly, it has the effect of facilitating miniaturization of elements and of effectively making use of the miniaturization to decrease the ON voltage.
    Type: Grant
    Filed: May 30, 2000
    Date of Patent: November 27, 2001
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Hideki Takahashi, Hidenori Nishihara, Masana Harada, Tadaharu Minato
  • Patent number: 6265735
    Abstract: A pin diode is formed by a p+ collector region, an n type buffer region, an n− region and an n+ cathode region. A trench is formed from the surface of n+ cathode region through n+ cathode region to reach n− region. An insulating film is formed along an inner wall surface of trench. A gate electrode layer is formed to oppose to the sidewall of n+ cathode region with insulating film interposed. A cathode electrode is formed to be electrically connected to n+ cathode region. An anode electrode is formed to be electrically connected to p+ collector region. The n+ cathode region is formed entirely over the surface between trenches extending parallel to each other. Thus, a power semiconductor device in which gate control circuit is simplified and which has good on property can be obtained.
    Type: Grant
    Filed: December 30, 1998
    Date of Patent: July 24, 2001
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tetsuo Takahashi, Katsumi Nakamura, Tadaharu Minato, Masana Harada
  • Patent number: 6177713
    Abstract: An anode electrode metal layer composed of aluminum is formed in a region on the inner side than an anode layer formed on a main surface of a semiconductor substrate. Thus, an impurity diffusion region from the innermost circumferential surface of said surface of field limiting innermost circumferential layer to the outermost circumferential surface of the anode electrode metal layer may be used as an electrical resistance. As a result, the hole density distributed from the bottom side of the field limiting innermost circumferential layer to a cathode layer when forward bias is applied may be reduced. As a result, when a reverse bias is applied, locally great recovery current passed from a cathode layer to the bottom of field limiting innermost circumferential layer may be restrained. Therefore, a diode capable of preventing destruction of a field limiting innermost circumferential layer when a reverse bias is applied may be provided.
    Type: Grant
    Filed: February 1, 1999
    Date of Patent: January 23, 2001
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Shinji Aono, Masana Harada
  • Patent number: 6107650
    Abstract: An insulated gate semiconductor device in which the ON voltage is decreased by providing strip like trenches (207) having gate electrodes (210) buried therein are formed in an upper main surface of a semiconductor base body (200), and an N.sup.+ emitter layer (206) is exposed in a ladder-like form in the upper main surface of the semiconductor base body interposed between adjacent trenches (207). Accordingly, even if the position of a zonal region (Ra) which is a contact surface with an emitter electrode (212) is shifted, the emitter electrode (212) is surely in contact with the N.sup.+ emitter layer (206). Furthermore, the ladder-like N.sup.+ emitter layer (206) is formed adjacent to the trench (207), so that a channel region (208) is formed without discontinuation along the trench (207). Accordingly, it has the effect of facilitating miniaturization of elements and of effectively making use of the miniaturization to decrease the ON voltage.
    Type: Grant
    Filed: February 14, 1995
    Date of Patent: August 22, 2000
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Hideki Takahashi, Hidenori Nishihara, Masana Harada, Tadaharu Minato
  • Patent number: 5977570
    Abstract: A pin diode is formed by a p.sup.+ collector region, an n type buffer region, an n.sup.- region and an n.sup.+ cathode region. A trench is formed from the surface of n.sup.+ cathode region through n.sup.+ cathode region to reach n.sup.- region. An insulating film is formed along an inner wall surface of trench. A gate electrode layer is formed to oppose to the sidewall of n.sup.+ cathode region with insulating film interposed. A cathode electrode is formed to be electrically connected to n.sup.+ cathode region. An anode electrode is formed to be electrically connected to p.sup.+ collector region. The n.sup.+ cathode region is formed entirely over the surface between trenches extending parallel to each other. Thus, a power semiconductor device in which gate control circuit is simplified and which has good on property can be obtained.
    Type: Grant
    Filed: July 18, 1996
    Date of Patent: November 2, 1999
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tetsuo Takahashi, Katsumi Nakamura, Tadaharu Minato, Masana Harada
  • Patent number: 5559348
    Abstract: A semiconductor device which allows an ON-state voltage to be lower than that of a conventional device and a method of manufacturing such a device. In this semiconductor device, a gate electrode is formed to have a planar area of its region covering a first base layer larger than that of its region covering a second base layer, thereby increasing a cathode short-circuit ratio of a cathode-shorted diode equivalent to this semiconductor device. As a result, a lower voltage than conventional ON-state can be obtained.
    Type: Grant
    Filed: June 5, 1995
    Date of Patent: September 24, 1996
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Kiyoto Watabe, Ikunori Takata, Masana Harada
  • Patent number: 5547886
    Abstract: In an SOI substrate including a single-crystal Si substrate (1b), an oxide film (20) and a single-crystal Si substrate (1a), there is formed an stepped wall surface (8) by selective removal of the single-crystal Si substrate (1a) to provide a thick oxide film (5) on the stepped wall surface (8). When a VDMOS (100) is formed in an active region of the single-crystal Si substrate (1b) above which the single-crystal Si substrate (1a) is absent and an MOS (101) having a thin oxide film (22) is formed in the single-crystal Si substrate (1a), the oxide film (5) is not damaged because it is thick. The thickness of the single-crystal Si substrate (1a) enables to be designed in accordance with the required thickness of the MOS (101).
    Type: Grant
    Filed: December 6, 1994
    Date of Patent: August 20, 1996
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Masana Harada