Patents by Inventor Shinichi Ishizawa

Shinichi Ishizawa 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: 8847290
    Abstract: A semiconductor device includes: a rectifying element; an electrode pad electrically connected to the rectifying element; and a resistance and a depletion transistor arranged between the rectifying element and the electrode pad, and electrically connected to each other. The semiconductor device has a configuration in which the rectifying element, the resistance, the depletion transistor, and the electrode pad are serially connected. The semiconductor device is configured to generate a gate potential of the depletion transistor based on a difference in potential across the resistance and to produce a depletion layer in a channel of the depletion transistor based on the gate potential. As a result, a semiconductor device having reasonably large current at low voltage and small current at high voltage can be obtained.
    Type: Grant
    Filed: December 28, 2012
    Date of Patent: September 30, 2014
    Assignee: Mitsubishi Electric Corporation
    Inventors: Shigeru Kusunoki, Shinichi Ishizawa
  • Publication number: 20130105866
    Abstract: A semiconductor device includes: a rectifying element; an electrode pad electrically connected to the rectifying element; and a resistance and a depletion transistor arranged between the rectifying element and the electrode pad, and electrically connected to each other. The semiconductor device has a configuration in which the rectifying element, the resistance, the depletion transistor, and the electrode pad are serially connected. The semiconductor device is configured to generate a gate potential of the depletion transistor based on a difference in potential across the resistance and to produce a depletion layer in a channel of the depletion transistor based on the gate potential. As a result, a semiconductor device having reasonably large current at low voltage and small current at high voltage can be obtained.
    Type: Application
    Filed: December 28, 2012
    Publication date: May 2, 2013
    Inventors: Shigeru KUSUNOKI, Shinichi Ishizawa
  • Patent number: 8373207
    Abstract: A semiconductor device includes: a rectifying element; an electrode pad electrically connected to the rectifying element; and a resistance and a depletion transistor arranged between the rectifying element and the electrode pad, and electrically connected to each other. The semiconductor device has a configuration in which the rectifying element, the resistance, the depletion transistor, and the electrode pad are serially connected. The semiconductor device is configured to generate a gate potential of the depletion transistor based on a difference in potential across the resistance and to produce a depletion layer in a channel of the depletion transistor based on the gate potential. As a result, a semiconductor device having reasonably large current at low voltage and small current at high voltage can be obtained.
    Type: Grant
    Filed: October 11, 2010
    Date of Patent: February 12, 2013
    Assignee: Mitsubishi Electric Corporation
    Inventors: Shigeru Kusunoki, Shinichi Ishizawa
  • Publication number: 20110140179
    Abstract: A semiconductor device includes: a rectifying element; an electrode pad electrically connected to the rectifying element; and a resistance and a depletion transistor arranged between the rectifying element and the electrode pad, and electrically connected to each other. The semiconductor device has a configuration in which the rectifying element, the resistance, the depletion transistor, and the electrode pad are serially connected. The semiconductor device is configured to generate a gate potential of the depletion transistor based on a difference in potential across the resistance and to produce a depletion layer in a channel of the depletion transistor based on the gate potential. As a result, a semiconductor device having reasonably large current at low voltage and small current at high voltage can be obtained.
    Type: Application
    Filed: October 11, 2010
    Publication date: June 16, 2011
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Shigeru Kusunoki, Shinichi Ishizawa
  • Patent number: 6709914
    Abstract: One aspect of the present invention is a to provide a process for manufacturing a pn junction diode, includes providing a semiconductor wafer having an n-type cathode layer formed thereon. Then, a p-type anode layer is formed on the n-type cathode layer so that a pn junction interface is formed between the n-type cathode layer and the p-type anode layer. Next, a cathode and anode electrodes are formed on the semiconductor wafer and the p-type anode layer, respectively. Lastly, first and second ions having average projection ranges Rp different from each other are simultaneously implanted up to the cathode layer so that one or more first and second implanted regions are formed alternately and overlapped side by side, thereby forming a lattice-defect region having a substantially uniform thickness beneath and adjacent to the pn junction interface.
    Type: Grant
    Filed: December 31, 2002
    Date of Patent: March 23, 2004
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Shinichi Ishizawa, Yoshifumi Tomomatsu
  • Patent number: 6670687
    Abstract: A semiconductor device having a silicon carbide layer of a singular conductivity type. The silicon carbide layer includes a surface having a first region, a second region, and a third region sandwiched between the first region and the second region. An anode electrode having a Schottky contact with the first region, a cathode electrode having an ohmic contact with the second region, and a control electrode having a Schottky contact with the third region are included in the semiconductor device.
    Type: Grant
    Filed: October 15, 2001
    Date of Patent: December 30, 2003
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Katsumi Satoh, Shinichi Ishizawa
  • Publication number: 20030141513
    Abstract: One aspect of the present invention is a to provide a process for manufacturing a pn junction diode, includes providing a semiconductor wafer having an n-type cathode layer formed thereon. Then, a p-type anode layer is formed on the n-type cathode layer so that a pn junction interface is formed between the n-type cathode layer and the p-type anode layer. Next, a cathode and anode electrodes are formed on the semiconductor wafer and the p-type anode layer, respectively. Lastly, first and second ions having average projection ranges Rp different from each other are simultaneously implanted up to the cathode layer so that one or more first and second implanted regions are formed alternately and overlapped side by side, thereby forming a lattice-defect region having a substantially uniform thickness beneath and adjacent to the pn junction interface.
    Type: Application
    Filed: December 31, 2002
    Publication date: July 31, 2003
    Applicant: MITSUBISHI DENKI KABUSHIKI KAISHA
    Inventors: Shinichi Ishizawa, Yoshifumi Tomomatsu
  • Publication number: 20030006471
    Abstract: On a first region (R1) of a surface (101S1) of an n-type silicon carbide layer (101), a Schottky drain electrode (102) is formed. Further, on a second region (R2), an ohmic source electrode (103) is formed. Furthermore, on a third region (R3), a Schottky gate electrode (104) is formed. Such a structure achieves a state where a Schottky barrier diode is formed between these electrodes (102 and 103). That can achieve a switching element using the silicon carbide layer with high breakdown voltage and low loss, which has both a switching function and a diode function (voltage blocking capability of reverse direction), with no pn junction formed in the silicon carbide layer, and thereby ensures reduction in size an weight of modules.
    Type: Application
    Filed: October 15, 2001
    Publication date: January 9, 2003
    Applicant: MITSUBISHI DENKI KABUSHIKI KAISHA
    Inventors: Katsumi Satoh, Shinichi Ishizawa