Patents by Inventor Hiroo Usui

Hiroo Usui 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).

  • Stacked polycrystalline silicon film of high and low conductivity layers
    Patent number: 4394191
    Abstract: A polycrystalline silicon film is implanted with an impurity in large amounts and is heated to be annealed, whereupon it is irradiated with a laser beam to be annealed.Thus, a polycrystalline silicon film of very low resistivity consisting of a second layer whose activated impurity concentration is equal to or below a solid solubility and a first layer whose activated impurity concentration is above the solid solubility is formed.
    Type: Grant
    Filed: December 17, 1980
    Date of Patent: July 19, 1983
    Assignee: Hitachi, Ltd.
    Inventors: Yasuo Wada, Hiroo Usui, Makoto Ohkura, Masanobu Miyao, Masao Tamura, Takashi Tokuyama
  • Method for fabricating a silicon device utilizing ion-implantation and selective oxidation
    Patent number: 4016007
    Abstract: A polycrystalline silicon layer is deposited by chemical vapor deposition method at a predetermined location on an oxide film grown by thermal oxidation on a surface of a monocrystal silicon substrate. Nitrogen ions are implanted in the outer surface of the polycrystalline silicon layer and the exposed surface of the oxide film. The whole surfaces are oxidized by wet oxidation so as to form a thick oxide layer at the surface of the oxide film which is not covered by the polycrystalline silicon layer.
    Type: Grant
    Filed: February 13, 1976
    Date of Patent: April 5, 1977
    Assignee: Hitachi, Ltd.
    Inventors: Yasuo Wada, Hiroo Usui, Mitsumasa Koyanagi, Mikio Ashikawa