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:
Apr. 05, 1994
Filed:
Apr. 23, 1992
Applicant:
Inventor:
Hajime Arai, Hyogo, JP;
Assignee:
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01L / ; H01L / ; H01L / ;
U.S. Cl.
CPC ...
257332 ; 257331 ; 257334 ; 257390 ; 257392 ; 257402 ;
Abstract
In a mask ROM device, a plurality of recesses extending parallel to each other are formed in a memory cell array region on the surface of a silicon substrate. In the direction intersecting the recesses, first and second transistor trains are formed in which select transistors and memory transistors are connected in series. The MOS transistors of the transistor trains have the sidewall of recess 5 formed as a channel region. A depletion implantation layer corresponding to data to be stored is formed on the sidewall of the recess. The first transistor train and the second transistor train are insulated and isolated from each other by an LOCOS isolation film.