Surface acoustic wave device and radio frequency front-end module

Abstract

The invention discloses a surface acoustic wave device and a radio frequency front end module, the surface acoustic wave device comprises a piezoelectric layer, a sound velocity layer and an interdigital electrode, and the interdigital electrode comprises a plurality of electrode fingers. The piezoelectric layer is provided with a first surface and a second surface which are oppositely arranged, the interdigital electrode is arranged on the first surface of the piezoelectric layer, and the sound velocity layer is arranged on the second surface of the piezoelectric layer; sound waves generated when the surface acoustic wave device works comprise surface acoustic waves and body waves; the surface acoustic wave device has a first characteristic depth, and the thickness of the piezoelectric layer is smaller than the first characteristic depth; wherein the first characteristic depth is related to the midline distance between two adjacent electrode fingers of the interdigital electrode, the bulk wave sound velocity of the piezoelectric crystal in the x direction and the working frequency. The sound velocity layer is directly arranged below the piezoelectric layer, the thickness of the piezoelectric layer is limited to be smaller than the first characteristic depth, and the thickness of the piezoelectric layer is reasonably reduced, so that the sound velocity of the surface wave is obviously improved or reduced, and meanwhile, the influence on the effects of other functional layers is avoided.

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