| 摘要 |
PROBLEM TO BE SOLVED: To provide a bulk acoustic resonator with high quality that reduces an energy loss by lateral mode oscillation. SOLUTION: This invention provides the bulk acoustic resonator (50) having a substrate (54), a depression (56) formed thereon, a 1st electrode (62), a 2nd electrode (58) and a piezoelectric material (60). The 1st electrode extends beyond the edges of the depression by a 1st distance (d2). The portion of the 2nd electrode has at least one edge that is offset from a corresponding edge by a 2nd distance (d1), the overlapped portion among the 1st and 2nd electrodes and the piezoelectric material forms the elastic cavity of the resonator, the 1st and 2nd regions have different impedances, as a result of the different materials located in the two regions. In addition, the 1st and 2nd distances (d2, d1) are approximately equal to a quarter-wavelength of an elastic wave traveling laterally across the respective regions. |
