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. 01, 2008
Filed:
Aug. 18, 2005
Moriya Iwai, Hyogo, JP;
Masaaki Yoshida, Hyogo, JP;
Hiroaki Nakanishi, Hyogo, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
A semiconductor device is capable of being applied with both a positive and a negative voltage to its control gate, and writing to its memory requires a low voltage. A control gate is formed on a memory unit region of a field oxide film, and an inter-layer silicon oxide film is formed on its surface. A gate oxide film for a non-volatile memory is formed on a P substrate between N type diffusion layers. The floating gate is formed on the inter-layer silicon oxide film, the field oxide film, and the gate oxide film for the non-volatile memory. Since a large coupling ratio between the control gate and the floating gate is available on the field oxide film, memory rewriting requires only a low voltage. Further, since the control gate is formed by a poly silicon film, both a positive voltage and a negative voltage can be applied to the control gate.