Acoustic wave guide device and method for minimizing trimming effects and piston mode instabilities
US8294331B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 7, 2011 |
| Grant date | Oct 23, 2012 |
| Priority date | — |
| Expiry date | Apr 7, 2031 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/49009
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An acoustic wave device operable as a piston mode wave guide includes electrodes forming an interdigital transducer on a surface of the piezoelectric substrate, wherein each of the plurality of electrodes is defined as having a transversely extending center region and transversely opposing edge regions for guiding an acoustic wave longitudinally through the transducer. A Silicon Oxide overcoat covers the transducer and a Silicon Nitride layer covers the Silicon Oxide overcoat within only the center and edge regions. The thickness of the Silicon Nitride layer is sufficient for providing a frequency modification to the acoustic wave within the center region and is optimized with a positioning of a Titanium strip within each of the opposing edge regions. The Titanium strip reduces the acoustic wave velocity within the edge regions with the velocity in the edge regions being less than the wave velocity within the transducer center region.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.