Patents by Inventor Ryoji Hagihara

Ryoji Hagihara 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).

  • Semiconductor memory device
    Patent number: 4656609
    Abstract: A semiconductor memory device includes a redundancy decoder circuit. The redundancy decoder circuit includes FAMOS transistors to which an address pattern, corresponding to an address of a defective memory cell to be replaced by a redundancy memory cell, is written at the floating gates of the FAMOS transistors. The FAMOS transistors are depletion type. Control gates thereof receive a voltage having ground level or lower during a usual memory access mode.
    Type: Grant
    Filed: April 2, 1986
    Date of Patent: April 7, 1987
    Assignee: Fujitsu Limited
    Inventors: Mitsuo Higuchi, Ryoji Hagihara