| US 7,498,717 B2 | ||
| Resonator, filter and fabrication of resonator | ||
| Tsuyoshi Yokoyama, Kawasaki (Japan); Tokihiro Nishihara, Kawasaki (Japan); Takeshi Sakashita, Kawasaki (Japan); Shinji Taniguchi, Kawasaki (Japan); Masafumi Iwaki, Kawasaki (Japan); Masanori Ueda, Yokohama (Japan); and Tsutomu Miyashita, Yokohama (Japan) | ||
| Assigned to Fujitsu Media Devices Limited, Yokohama (Japan); and Fujitsu Limited, Kawasaki (Japan) | ||
| Filed on Mar. 30, 2005, as Appl. No. 11/92,979. | ||
| Claims priority of application No. 2004-101878 (JP), filed on Mar. 31, 2004. | ||
| Prior Publication US 2005/0218754 A1, Oct. 06, 2005 | ||
| Int. Cl. H01L 41/09 (2006.01) | ||
| U.S. Cl. 310—320 | 4 Claims |
| 1. A filter having a series-arm resonator and a parallel-arm resonator, in which each of the resonators includes a common
substrate, a common piezoelectric thin film having a first surface on which a first electrode film is formed and a second
surface on which a second electrode film is formed, and a frequency adjustment film provided on the second electrode film,
wherein:
the frequency adjustment films of the series-arm and parallel-arm resonators are partially provided on the second electrode
film and are located in only overlapping regions in which the first and second electrodes overlap with each other across the
piezoelectric thin film; and
the first electrodes of the series-arm and parallel-arm resonators facing cavities formed below the overlapping regions of
the series-arm and parallel-arm resonators.
|