CPC H03H 9/6423 (2013.01) [H03H 3/08 (2013.01); H03H 9/02897 (2013.01); H03H 9/059 (2013.01); H03H 9/1092 (2013.01)] | 12 Claims |
1. A surface acoustic wave (SAW) filter, comprising:
a bottom substrate;
a piezoelectric layer disposed above the bottom substrate, the piezoelectric layer having a bottom surface facing the bottom substrate and a top surface opposite to the bottom surface;
a lower cavity disposed below the piezoelectric layer;
an interdigital transducer (IDT) disposed on the top surface of the piezoelectric layer; and
a back electrode disposed on the bottom surface of the piezoelectric layer,
wherein the back electrode includes a first surface facing the piezoelectric layer, a second surface facing the bottom substrate, and a side surface connecting the first surface and a second surface, and
at least a portion of the side surface of the back electrode is exposed in the lower cavity.
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