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:
Jun. 16, 2009
Filed:
Apr. 30, 2004
Yoichi Okita, Kawasaki, JP;
Junichi Watanabe, Kawasaki, JP;
Naoya Sashida, Kawasaki, JP;
Fujitsu Microelectronics Limited, Tokyo, JP;
Abstract
An AlOfilm for covering a ferroelectric capacitor is formed by a sputtering process. The thickness of the AlOfilm is preferably optimized according to amount of remanent polarization and fatigue tolerance required for the ferroelectric capacitor, for example, 10 nm to 100 nm. Next, oxygen is supplied to a PZT film via the AlOfilm by executing a heat treatment in an oxygen atmosphere. As a result, an oxygen deficit in the PZT film is made up for. At this time, evaporation of Pb in the PZT film is suppressed because of the AlOfilm, and deterioration of the fatigue tolerance responsive to decrease of Pb amount is suppressed. Subsequently, another AlOfilm is formed as a second protective film by the sputtering process for opposing the deterioration factor in later process. The thickness of the AlOfilm is preferably the thickness which sufficiently protects the ferroelectric capacitor from the deterioration factor in later wiring process.