Patents by Inventor Takafumi Shimotori

Takafumi Shimotori 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).

  • Publication number: 20110199811
    Abstract: According to an embodiment, there are provided a non-volatile semiconductor memory device includes: a memory cell array; a control circuit performing a series of operations to each memory cell and determining, as a defective memory cell, a memory cell whose data retention property does not satisfy a criteria, the series of operations including an operation applying a first bias to the memory cell in a forward direction, and including an operation thereafter applying a second bias to the memory cell in a reverse direction; a storage unit storing an address of the defective memory cell; and an address control unit performing a control to avoid storing data in the defective memory cell whose address is stored in the storage unit.
    Type: Application
    Filed: September 17, 2010
    Publication date: August 18, 2011
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Hiroshi KANNO, Takayuki TSUKAMOTO, Takahiko SASAKI, Takafumi SHIMOTORI
  • Publication number: 20110051498
    Abstract: According to one embodiment, a semiconductor memory device includes a memory cell, a power supply circuit, an interconnection and a discharging circuit. The memory cell includes a variable resistance element whose resistance varies by application of a voltage. The power supply circuit outputs the voltage to be applied to the memory cell. The interconnection is formed between the power supply circuit and the memory cell and supplies the voltage output from the power supply circuit to the memory cell. The discharging circuit is connected to the interconnection. The discharging circuit discharges electric charge accumulated in the interconnection after a first operation of applying the voltage to the memory cell is ended and before a second operation of applying the voltage to the memory cell next is started.
    Type: Application
    Filed: September 1, 2010
    Publication date: March 3, 2011
    Inventor: Takafumi SHIMOTORI