| CPC H03H 9/02228 (2013.01) [H03H 9/02015 (2013.01); H03H 9/02102 (2013.01)] | 20 Claims |
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1. An acoustic wave device comprising:
a support including a support substrate;
a piezoelectric layer on the support;
an IDT electrode on the piezoelectric layer and including two busbars and a plurality of electrode fingers, the two busbars being a busbar pair and facing each other; and
a dielectric film that is provided on the piezoelectric layer so as to overlap at least a portion of the IDT electrode in plan view; wherein
a ratio d/p is less than or equal to about 0.5, where a thickness of the piezoelectric layer is d and a center-to-center distance between centers of adjacent ones of the electrode fingers is p;
MR≤about 1.75(d/p)+0.075 is satisfied, where a metallization ratio of the plurality of electrode fingers with respect to the intersection region is MR;
a cavity that opens on a side of the piezoelectric layer is provided in the support, and, in plan view, at least a portion of the IDT electrode and the cavity overlap each other;
the IDT electrode includes an intersection region and two gap regions, the intersection region being a region in which the adjacent ones of the electrode fingers overlap each other when viewed in a direction in which the adjacent ones of the electrode fingers face each other, the two gap regions each being positioned between the intersection region and a corresponding one of the two busbars; and
the dielectric film is provided at at least a portion of the two gap regions, and a thermal conductivity of the dielectric film is higher than a thermal conductivity of the piezoelectric layer.
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