Acoustic wave device

Abstract

An acoustic wave device includes a support with a thickness in a first direction, a piezoelectric layer extending on the support in the first direction, and an interdigital transducer electrode on a principal surface of the piezoelectric layer. The interdigital transducer electrode includes first electrode fingers extending in a second direction crossing the first direction, a first busbar electrode connected to the first electrode fingers, second electrode fingers extending in the second direction and facing corresponding ones of the first electrode fingers in a third direction perpendicular or substantially perpendicular to the second direction, and a second busbar electrode connected to the second electrode fingers. The piezoelectric layer includes a piezoelectric multilayer structure in a gap region between at least one first electrode finger and the second busbar electrode, or between at least one second electrode finger and the first busbar electrode, in plan view in the first direction. The piezoelectric multilayer structure includes first and second piezoelectric bodies with different dielectric polarizations.