The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 19, 2013
Filed:
Sep. 17, 2010
Applicants:
Noboru Shibata, Kawasaki, JP;
Kazunori Kanebako, Yokohama, JP;
Inventors:
Noboru Shibata, Kawasaki, JP;
Kazunori Kanebako, Yokohama, JP;
Assignee:
Kabushiki Kaisha Toshiba, Tokyo, JP;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11C 11/34 (2006.01);
U.S. Cl.
CPC ...
Abstract
According to one embodiment, a semiconductor storage device includes a memory cell array and a control circuit. The distribution state of the threshold voltages of the memory cells is monitored by the read operation, the distribution state of the threshold voltages of the memory cells after the soft erasure is monitored, and an erase voltage is set based on the monitored results. Thus, the erase voltage can be precisely set without depending on the threshold voltage distribution of the memory cell before the erasure.