Patents by Inventor Hironori Wakai

Hironori Wakai 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).

  • Nonvolatile semiconductor memory device
    Patent number: 8576606
    Abstract: A nonvolatile semiconductor memory device according to an embodiment herein includes a memory cell array. The memory cell array includes memory cells each provided between a first line and a second line and each including a variable resistor. A control circuit applies through the first and second lines a voltage necessary for a forming operation of the memory cell. A current limiting circuit limits a value of a current flowing across the memory cell during the forming operation to a certain limit value. The control circuit repeats an operation of applying the voltage by setting the limit value to a certain value and an operation of changing the limit value from the certain value, until forming of the memory cell is achieved.
    Type: Grant
    Filed: March 21, 2011
    Date of Patent: November 5, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tetsuji Kunitake, Takashi Shigeoka, Takayuki Tsukamoto, Hironori Wakai, Hisashi Kato
  • NONVOLATILE SEMICONDUCTOR MEMORY DEVICE
    Publication number: 20110235401
    Abstract: A nonvolatile semiconductor memory device according to an embodiment herein includes a memory cell array. The memory cell array includes memory cells each provided between a first line and a second line and each including a variable resistor. A control circuit applies through the first and second lines a voltage necessary for a forming operation of the memory cell. A current limiting circuit limits a value of a current flowing across the memory cell during the forming operation to a certain limit value. The control circuit repeats an operation of applying the voltage by setting the limit value to a certain value and an operation of changing the limit value from the certain value, until forming of the memory cell is achieved.
    Type: Application
    Filed: March 21, 2011
    Publication date: September 29, 2011
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Tetsuji KUNITAKE, Takashi Shigeoka, Takayuki Tsukamoto, Hironori Wakai, Hisashi Kato