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:
Jul. 18, 2000
Filed:
Apr. 24, 1998
Masanori Yoshimi, Fukuyama, JP;
Shinichi Sato, Fukuyama, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
A plurality of blocks of memory cell transistors are formed on the respective isolated wells. In a write stage, a predetermined write-stage well voltage is applied to the well of a selected block including the memory cell transistors to be subjected to a write operation, a bias voltage is applied to the well of each of the remaining, non-selected blocks to increase a threshold voltage of the memory cell transistors of each non-selected block, in comparison with a threshold voltage determined by the predetermined write-stage well voltage, and a voltage is applied to the control gates of the memory cell transistors of each non-selected block to reduce a difference between a potential of the floating gate of each memory cell transistor of each non-selected block and a write-stage drain voltage applied to the drain of the memory cell transistor through the associated bit line such that a source-drain leak current of each memory cell transistor in the non-selected blocks falls in a permissible range.