Patents by Inventor Tadaaki Souma

Tadaaki Souma 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: 7615839
    Abstract: Since VF and IR characteristics of a Schottky barrier diode are in a trade-off relationship, there has heretofore been a problem that an increase in a leak current is unavoidable in order to realize a low VF. Moreover, there has been a known structure which suppresses the leak current in such a manner that a depletion layer is spread by providing P+ regions and a pinch-off effect is utilized. However, in reality, it is difficult to completely pinch off the depletion layer. P+ type regions are provided, and a low VF Schottky metal layer is allowed to come into contact with the P+ type regions and depletion regions therearound. A low IR Schottky metal layer is allowed to come into contact with a surface of a N type substrate between the depletion regions. When a forward bias is applied, a current flows through the metal layer of low VF characteristic. When a reverse bias is applied, a current path narrowed by the depletion regions is formed only in the metal layer portion of low IR characteristic.
    Type: Grant
    Filed: February 16, 2005
    Date of Patent: November 10, 2009
    Assignee: Sanyo Electric Co., Ltd.
    Inventors: Tadaaki Souma, Tadashi Natsume
  • Publication number: 20090029518
    Abstract: Disclosed is a method of fabricating a Schottky barrier diode, which comprises the steps of laminating an N? type epitaxial layer having a thickness of 2 to 4 ?m, on an N+ type substrate layer, to form a semiconductor substrate; forming a P+ type guard ring at a given position of epitaxial layer, from the side of a top surface of the semiconductor substrate; dividing a portion of the epitaxial layer surrounded by the guard ring, into a plurality of unit regions each having one side length of 0.1 to 0.
    Type: Application
    Filed: July 22, 2008
    Publication date: January 29, 2009
    Applicant: Toko, Inc.
    Inventor: Tadaaki Souma
  • Publication number: 20050194610
    Abstract: Since VF and IR characteristics of a Schottky barrier diode are in a trade-off relationship, there has heretofore been a problem that an increase in a leak current is unavoidable in order to realize a low VF. Moreover, there has been a known structure which suppresses the leak current in such a manner that a depletion layer is spread by providing P+ regions and a pinch-off effect is utilized. However, in reality, it is difficult to completely pinch off the depletion layer. P+ type regions are provided, and a low VF Schottky metal layer is allowed to come into contact with the P+ type regions and depletion regions therearound. A low IR Schottky metal layer is allowed to come into contact with a surface of a N type substrate between the depletion regions. When a forward bias is applied, a current flows through the metal layer of low VF characteristic. When a reverse bias is applied, a current path narrowed by the depletion regions is formed only in the metal layer portion of low IR characteristic.
    Type: Application
    Filed: February 16, 2005
    Publication date: September 8, 2005
    Applicant: Sanyo Electric Co., Ltd.
    Inventors: Tadaaki Souma, Tadashi Natsume