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:
Aug. 01, 1989
Filed:
Dec. 22, 1987
Applicant:
Inventors:
Natsuro Tsubouchi, Itami, JP;
Masafumi Kimata, Itami, JP;
Assignee:
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01L / ;
U.S. Cl.
CPC ...
437203 ; 437 47 ; 437 60 ; 437228 ; 437918 ;
Abstract
A semiconductor memory device such as a MOS dynamic RAM comprises transistor portions (2, 3 and 5) for writing and reading a signal and capacitor portions (1, 2, 6 and 9) by pn junction for storing a signal. The capacitor portions have preferably as large a capacitance as possible. For this purpose, a capacitor hole (7) is formed in a p type semiconductor substrate (6) and an n type semiconductor region (9) is provided along the capacitor hole (7) so that the pn junction area therebetween is increased and the capacitance is made large.