Bulk acoustic wave filter device and method of manufacturing the same
US10637430B2 · kind B2 · utility
0Cited by
4References
21Claims
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Key dates
| Filing date | Jun 13, 2017 |
| Grant date | Apr 28, 2020 |
| Priority date | — |
| Expiry date | May 2, 2038 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H2003/021
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A bulk acoustic wave filter device includes a substrate, a lower electrode on the substrate, a piezoelectric layer covering at least a portion of the lower electrode, and an upper electrode covering at least a portion of the piezoelectric layer. The upper electrode has a density reduction layer disposed on at least a portion thereof, except a central portion of a resonance region of the bulk acoustic wave filter device that deforms and vibrates with the piezoelectric layer during activation of the piezoelectric layer. The density reduction layer has a density lower than a density of other portions of the upper electrode.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.