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:
Aug. 30, 2005
Filed:
May. 10, 2002
Tetsuo Yamada, Ube, JP;
Keigo Nagao, Ube, JP;
Chisen Hashimoto, Ube, JP;
Morito Akiyama, Tosu, JP;
Naohiro Ueno, Tosu, JP;
Hiroshi Tateyama, Tosu, JP;
Tetsuo Yamada, Ube, JP;
Keigo Nagao, Ube, JP;
Chisen Hashimoto, Ube, JP;
Morito Akiyama, Tosu, JP;
Naohiro Ueno, Tosu, JP;
Hiroshi Tateyama, Tosu, JP;
UBE Industries, Ltd., Yamaguchi, JP;
National Institute of Advanced Industrial Science and Technology, Tokyo, JP;
Abstract
A thin film bulk acoustic resonator comprises a substrate () of a silicon single crystal, a base film () formed on the substrate () and composed of a dielectric film mainly containing silicon oxide, and a piezoelectric stacked structure () formed on the base film (). A vibratory section () composed of a part of the base film () and a part of the piezoelectric stacked structure (). The piezoelectric stacked structure () includes a lower electrode (), a piezoelectric film (), and an upper electrode () formed in this order from below. The substrate () had a via hole () in the region corresponding to the vibratory section (). The via hole forms a space for allowing vibration of the vibratory section (). The piezoelectric film () is an aluminum nitride thin film containing 0.2 to 3.0 atom % of alkaline earth metal and/or a rare earth metal. Thus, the thin film bulk acoustic resonator has a high performance such as a large electromechanical coupling coefficient, an excellent acoustic quality factor (Q) and an excellent frequency-temperature characteristic.