BOUNDARY ACOUSTIC WAVE DEVICE AND METHOD FOR MANUFACTURING SAME

摘要

Disclosed is a boundary acoustic wave device which can be manufactured with high yield. Specifically disclosed is a boundary acoustic wave device (1) which comprises a first medium (11) that is formed of a piezoelectric body, a second medium (12) that is formed of a dielectric body, a third medium (13) that is formed of a dielectric body, and an IDT electrode (20) that is formed in the boundary between the first medium (11) and the second medium (12). The acoustic velocity of the second medium (12) is lower than the acoustic velocities of the first and third media (11, 13). The IDT electrode (20) has a first electrode layer (21), a second electrode layer (22) and a third electrode layer (23). The density of the second electrode layer (22) is lower than the densities of the first and third electrode layers (21, 23). When the thickness of the first electrode layer (21) is represented by h1 and the thickness of the third electrode layer (23) is represented by h3, the boundary acoustic wave device (1) satisfies the following relation: 0.55 < h3/(h1 + h3) < 0.95.