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. 18, 1997
Filed:
Oct. 31, 1995
Vasanta Chivukula, Nepean, CA;
Pak K Leung, Kanata, CA;
Northern Telecom Limited, Montreal, CA;
Abstract
An improved electrode structure compatible with ferroelectric capacitor dielectrics is provided. In particular, a multilayer electrode having improved adhesion to ferroelectric materials such as PZT is formed comprising a first layer of a noble metal, a second layer of another metal and a thicker layer of the noble metal, which are annealed to cause controlled interdiffusion of the layers forming a mixed metal surface layer having a rough interface with the dielectric layer. For example, the first two layers comprise relatively thin .about.200.ANG. layers of Pt and Ti, and then a thicker layer of the main, first, electrode material is deposited on top. Non- uniform interdiffusion of the layers during annealing causes intermixing of the Pt and Ti layers at the interfaces forming a Pt/Ti alloy having a rough surface. The rough surface, and particularly hillocks formed at the interface, penetrate into the ferroelectric films, and anchor the electrode material to the dielectric. Improved adhesion of the conductive electrode material improves integrity of this interface during subsequent processing.