摘要 |
A boundary acoustic wave device includes a piezoelectric substrate having an upper surface in which grooves are provided, IDT electrodes which are at least partially embedded in the grooves in the upper surface of the piezoelectric substrate in a thickness direction of the IDT electrodes, and first and second dielectric layers stacked on the upper surface of the piezoelectric substrate. The second dielectric layer has an acoustic velocity greater than that of the first dielectric layer. |