Film bulk acoustic resonator
US6936837B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | May 10, 2002 |
| Grant date | Aug 30, 2005 |
| Priority date | — |
| Expiry date | Aug 20, 2022 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S438/90
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A thin film bulk acoustic resonator comprises a substrate (12) of a silicon single crystal, a base film (13) formed on the substrate (12) and composed of a dielectric film mainly containing silicon oxide, and a piezoelectric stacked structure (14) formed on the base film (13). A vibratory section (21) composed of a part of the base film (13) and a part of the piezoelectric stacked structure (14). The piezoelectric stacked structure (14) includes a lower electrode (15), a piezoelectric film (16), and an upper electrode (17) formed in this order from below. The substrate (12) had a via hole (20) in the region corresponding to the vibratory section (21). The via hole forms a space for allowing vibration of the vibratory section (21). The piezoelectric film (16) 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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.