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:
Jan. 13, 1998
Filed:
Sep. 11, 1995
Naoko Otani, Itami, JP;
Toshiharu Katayama, Itami, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
A non-volatile semiconductor storage device with which a multi-value memory is realized and the amount of information storable is increased without increasing the number of memory transistors and the area occupied thereby. A gate electrode portion 20a of each memory transistor has a two-layer floating gate structure comprising two floating gate electrodes 22a, 22b and a control gate electrode 24 which are substantially vertically laminated one above another. The non-volatile semiconductor storage device is thereby constructed as a multi-value memory capable of providing a state '1' where electrons are injected into the first floating gate electrode 22a, a state '0' where electrons are injected into the first and second floating gate electrodes 22a, 22b, and a state '2' where electrons are withdrawn from the first and second floating gate electrodes 22a, 22b.