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. 12, 1999
Filed:
Feb. 26, 1998
Hiroaki Nakanishi, Hyogo, JP;
Satoru Taji, Hyogo, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
A memory cell of a memory device is constructed such that a source diffusion layer is divided into blocks each containing 16 word lines, and such that a drain diffusion layer is not divided. Each segment of the source diffusion layer is connected to a metal bit line via a block selection MOS transistor. The metal bit line is formed on an insulating film provided on the source diffusion layer so as to be parallel with the source diffusion layer. The block selection MOS transistor is connected to the metal bit line via a contact hole. A gate electrode of the block selection MOS transistor is formed of a polysilicon film for providing a selection gate used to form a word line of the memory cell. A source diffusion layer and a drain diffusion layer of the block selection MOS transistor are formed of the same material as the source diffusion layer of the memory cell and the drain diffusion layer of the memory cell.