Thin film acoustic resonator and method of producing the same
US6842088B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 9, 2002 |
| Grant date | Jan 11, 2005 |
| Priority date | — |
| Expiry date | Jul 9, 2022 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/49155
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A pit (52) is formed in a substrate comprising a silicon wafer (51) on a surface of which a silicon oxide thin layer (53) is formed. A sandwich structure (60) comprising a piezoelectric layer (62) and lower and upper electrodes (61, 63) joined to both surfaces of the piezoelectric layer is disposed so as to stride over the pit (52). The upper surface of the lower electrode (61) and the lower surface of the piezoelectric layer (62) joined to the upper surface of the lower electrode are treated so that the RMS variation of the height thereof is equal to 25 nm or less. The thickness of the lower electrode (61) is set to 150 nm or less. According to such a structure, there is provided a high-performance thin film bulk acoustic resonator which are excellent in electromechanical coupling coefficient and acoustic quality factor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.