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. 23, 1999
Filed:
Mar. 10, 1997
Vasanta Chivukula, Nepean, CA;
Pak K Leung, Gilbert, AZ (US);
Northern Telecom Limited, Ottawa, CA;
Abstract
A ferroelectric dielectric for microwave applications is provided including a polycrystalline perovskite phase of lead zirconate titanate dielectric material. Small grain size material is provided by a low temperature process, by a rapid thermal annealing process. A layer of amorphous ferroelectric precursor material is deposited and annealed in an oxygen containing atmosphere in the presence of water vapour, preferably with the addition of a few percent of ozone, and at a temperature of less than 500.degree. C. Advantageously, the method provides for formation of a ferroelectric material including lead zirconate titanate with a grain size less than 20 nm, with low film stress, high dielectric constant and low leakage current, which has excellent ferroelectric characteristics up to 10 GHz. This material has applications for capacitors, as filters, decoupling, coupling, and bypass elements and also for high frequency surface acoustic wave devices.