CPC H03H 9/173 (2013.01) [H03H 9/02031 (2013.01); H03H 9/13 (2013.01)] | 11 Claims |
1. A bulk acoustic wave (BAW) resonator, comprising:
a substrate;
a piezoelectric layer disposed above the substrate;
a first electrode disposed below the piezoelectric layer;
a second electrode disposed above the piezoelectric layer;
a first dielectric layer, a second dielectric layer, and a third dielectric layer disposed between the substrate and the piezoelectric layer; and
a bonding layer disposed between the third dielectric layer and the substrate,
wherein the first dielectric layer is disposed below the piezoelectric layer and includes a cavity,
the third dielectric layer is disposed below the first dielectric layer and includes a protruding structure protruding towards the piezoelectric layer, and
the second dielectric layer overlays the third dielectric layer including the protruding structure, the second dielectric layer and the protruding structure of the third dielectric layer constituting a double-wall boundary structure surrounding the cavity.
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