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. 28, 1990
Filed:
Mar. 25, 1988
Yoshinori Okumura, Hyogo, JP;
Akihiko Ohsaki, Hyogo, JP;
Kazuyuki Sugahara, Hyogo, JP;
Tatsuhiko Ikeda, Hyogo, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
A semiconductor memory device includes a first trench serving as a memory cell formed in a p type semiconductor substrate, a first n type semiconductor region formed adjacent to the trench region and on the major surface of the semiconductor substrate, a conductive layer serving as an electron active region formed adjacent to the first n type region and on the major surface of the semiconductor substrate, a second n type semiconductor region formed adjacent to the electron active region and on the major surface of the semiconductor substrate, a second trench formed adjacent to the second n type semiconductor region in the major surface of the semiconductor substrate which is shallower than the first trench, an interconnection layer serving as a bit line formed in a self-aligning manner in the sidewall portion of the second trench which is shallower than the first trench and a gate electrode serving as a word line formed in the upper portion of the conductive layer through an oxide film.