Patents by Inventor Mituhiko Kitagawa

Mituhiko Kitagawa 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: 5028974
    Abstract: A semiconductor switching device includes a high resistance first base layer of n-type formed on a first emitter layer of p-type through a low resistance buffer layer of n.sup.+ -type, second base layer of p-type formed on the first base layer, second emitter layers of n.sup.+ -type separately formed on the second base layer, anode and cathode main electrodes formed in contact with the first and second emitter layers, and a gate electrode formed in contact with the second base layer. Part of the low resistance buffer layer is exposed to the surface of the first emitter layer and is made contact with the anode main electrode to constitute a shorting portion. The width of the shorting portion is set smaller than one tenth of that of the second emitter layer in a longitudinal direction.
    Type: Grant
    Filed: February 5, 1990
    Date of Patent: July 2, 1991
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Mituhiko Kitagawa, Tsuneo Ogura, Hiromichi Ohashi, Yoshinari Uetake, Yoshio Yokota, Kazuo Watanuki