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. 26, 1999
Filed:
May. 05, 1997
Applicant:
Inventors:
Hiroki Shirai, Tokyo, JP;
Taishi Kubota, Tokyo, JP;
Ichiro Honma, Tokyo, JP;
Hirohito Watanabe, Tokyo, JP;
Haruhiko Ono, Tokyo, JP;
Takeshi Okazawa, Tokyo, JP;
Assignee:
NEC Corporation, Tokyo, JP;
Primary Examiner:
Int. Cl.
CPC ...
H01L / ;
U.S. Cl.
CPC ...
257317 ; 257900 ;
Abstract
There is disclosed a nonvolatile semiconductor memory device, which is capable of maintaining a high capacitance ratio even when a memory cell is formed in a micronized size without increasing the number of manufacturing steps. In a flash memory having buried diffusion layer type cells, a source region and drain regions and are formed in self alignment with a polycrystalline film pattern which has a polycrystalline silicon film having projecting and recessing parts in its upper surface.