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:
Nov. 28, 2000
Filed:
Jul. 08, 1998
Koji Watanabe, Kanagawa, JP;
Masahiro Tanaka, Kanagawa, JP;
Sony Corporation, Tokyo, JP;
Abstract
A ferroelectric capacitor and a method of manufacturing the same are provided for reducing a crystal grain size while maintaining excellent ferroelectric properties so as to achieve a reduction in device size. A lower electrode, a ferroelectric layer and an upper electrode are formed on a substrate. The ferroelectric layer is formed into a plurality of stacked layers including an oxide of a layered crystal structure (Bi.sub.x (Sr, Ca, Ba).sub.y (Ta, Nb).sub.2 O.sub.9 .+-..sub.d). Proportion `y` of (Sr, Ca, Ba) in at least one of the layers is different from those of the other layers. That is, a variation in proportion `y` of (Sr, Ca, Ba) is provided in the ferroelectric layer. As a result, excellent ferroelectric properties are obtained and the crystal grain size of the oxide is reduced.