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:
Jun. 17, 2003
Filed:
Apr. 07, 1999
Akihiko Satoh, Hachioji, JP;
Takayuki Kawahara, Higashiyamato, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
The present invention discloses a nonvolatile semiconductor memory device including a memory cell array composed of a plurality of memory cells, each of which is formed with a gate insulating film, a floating gate electrode, an insulating film between electrodes, and a control electrode formed respectively in a first conductor type semiconductor area, as well as a second conductor type source area and a second conductor type drain area formed respectively in the firs conductor type semiconductor area, and programming and erasing data by controlling the amount of electrons in the floating gate electrode, wherein the nonvolatile semiconductor memory device further includes at least; means for applying a predetermined first operation voltage to the memory cell thereby to inject or eject electrons in or from the floating gate electrode; means for applying a second operation voltage to the memory cell after the application of the first operation voltage to give an electric field with a polarity opposite to that of the electric field applied with the application of the first operation voltage to an insulating film area around the floating gate through which electrons pass when the first operation voltage is applied; means for verifying the threshold voltage in the memory cell after the application of the second operation voltage; and means for deciding whether to repeat the operations following the application of the first operation voltage after the verify operation.