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.

Date of Patent:
May. 03, 1994

Filed:

Jan. 13, 1993
Applicant:
Inventors:

Yuichi Ando, Takarazuka, JP;

Koichi Sogawa, Minoo, JP;

Norio Yoshida, Ikeda, JP;

Masao Kiyohara, Takarazuka, JP;

Assignee:

Ricoh Company, Ltd., Tokyo, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01L / ; H01L / ;
U.S. Cl.
CPC ...
437 48 ; 437 52 ; 437 41 ; 437238 ; 437244 ; 257333 ; 257390 ; 257394 ; 148D / ; 148D / ;
Abstract

A semiconductor memory device comprising a substrate, a longitudinal source diffusion layer for a plurality of memory transistor source regions continuously formed on the substrate, and a longitudinal drain diffusion layer for a plurality of memory transistor drain regions continuously formed on the substrate in parallel to the source diffusion layer. A word line is formed crossing over the diffusion layers. And an electrically insulating film is interposed between the word line and the diffusion layers. The insulating film is thicker than a gate oxide film formed between the diffusion layers.


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