CPC H03H 9/205 (2013.01) [H03H 3/02 (2013.01); H03H 3/04 (2013.01); H03H 9/02015 (2013.01); H03H 9/02086 (2013.01); H03H 9/173 (2013.01); H03H 9/175 (2013.01); H03H 9/54 (2013.01); H03H 9/564 (2013.01); H03H 9/568 (2013.01); H04B 1/40 (2013.01); H03H 2003/0442 (2013.01)] | 20 Claims |
1. A bulk acoustic wave resonator comprising:
a first electrode over an acoustic reflector;
a piezoelectric layer over the first electrode;
a second electrode over the piezoelectric layer;
a patterned mass loading layer at least contributing to a difference in mass loading between a main acoustically active region of the bulk acoustic wave resonator and a recessed frame region of the bulk acoustic wave resonator, the patterned mass loading layer being in both the main acoustically active region and the recessed frame region, the patterned mass loading layer having a higher duty factor in the main acoustically active region than in the recessed frame region, the patterned mass loading layer arranged to affect a resonant frequency of the bulk acoustic wave resonator; and
another layer in both the recessed frame region and the main acoustically active region, the another layer providing less mass loading in the recessed frame region than in the main acoustically active region.
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