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:
Mar. 07, 2000
Filed:
Dec. 01, 1997
Applicant:
Inventors:
Osamu Sakamoto, Hyogo, JP;
Natsuo Ajika, Hyogo, JP;
Assignee:
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01L / ;
U.S. Cl.
CPC ...
257315 ; 257321 ; 257506 ; 257510 ;
Abstract
A nonvolatile semiconductor memory device with trench isolation having sufficient capability of isolating memory cells is provided. A trench formed as a line in the main surface of semiconductor substrate is filled with a first insulating film. On semiconductor substrate on both sides of trench, a first gate electrode is provided with a first oxide film interposed. On the first gate electrode, a second gate electrode is provided with a second insulating film interposed. An angle formed by a side wall upper surface of trench and the surface of semiconductor substrate is smaller than 90.degree..