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:
Oct. 27, 1998
Filed:
Sep. 22, 1997
Maarten J Van Dort, Eindhoven, NL;
Andrew J Walker, Palo Alto, CA (US);
U.S. Philips Corporation, New York, NY (US);
Abstract
An (E)EPROM is provided in which information is written with hot electrons generated in the channel current at the source side of the channel instead of at the drain side, as is usual. To obtain the electric field distribution in the channel 6 necessary for this, the gate oxide 10 is provided with a thickened portion 13 adjacent the source zone 4 so that locally a strong lateral electric field is induced in the channel at higher gate voltages. An efficient charge transport of electrons to the floating gate 9 is obtained through this lateral electric field in the channel and the comparatively high electric field in the gate oxide. The thickened portion of the gate oxide may be obtained in a simple manner through thermal oxidation. To prevent the formation of strong fields at the drain side of the channel, the drain is preferably provided with an LDD structure 5a which adjoins the gate oxide. As a result, Fowler-Nordheim tunnelling through this thin gate oxide may also be used for erasing.