Patents by Inventor Katsuhiro Hayasaka

Katsuhiro Hayasaka 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).

  • Method of fabricating a semiconductor integrated circuit
    Patent number: 4898837
    Abstract: A method of fabricating a semiconductor integrated circuit comprises the steps of: forming buried layers in predetermined regions of a semiconductor substrate; forming an epitaxial layer covering the substrate and the buried layers; forming isolation regions dividing the epitaxial layer into a plurality of islands; selectively implanting ions to form a base region of a vertical bipolar transistor in a surface layer of one island and simultaneously to form a resistor region in a surface layer of another island; and selectively diffusing impurities into a surface layer of the base region, to form an emitter region of the vertical bipolar transistor.
    Type: Grant
    Filed: November 15, 1988
    Date of Patent: February 6, 1990
    Assignee: Sanyo Electric Co., Ltd.
    Inventors: Kazuo Takeda, Nobuyuki Sekikawa, Katsuhiro Hayasaka, Chikao Fujunuma, Nobuo Itoh, Tetsuya Kubota