Patents by Inventor Takeshi Tokuyama

Takeshi Tokuyama 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).

  • Insulated gate field effect transistor having drain region containing low impurity concentration layer
    Patent number: 4005450
    Abstract: An insulated gate field effect transistor formed on one main surface of a semiconductor substrate comprises a drain region the impurity concentration of which is lower than twice that of the semiconductor substrate and the conductivity type is reverse to that of the substrate and a region of a high impurity concentration, formed in the low impurity concentration region, the conductivity type of which is the same as that of the low impurity concentration region.
    Type: Grant
    Filed: December 16, 1974
    Date of Patent: January 25, 1977
    Assignee: Hitachi, Ltd.
    Inventors: Isao Yoshida, Takeshi Tokuyama, Shigeru Nishimatsu, Takahide Ikeda