Piezoelectric acoustic resonator with improved TCF manufactured with piezoelectric thin film transfer process

An acoustic resonator comprising:

• a support, portions of the support defining a reflector;
• a first electrode extending over the reflector as viewed from a cross-sectional plane of the resonator;
• a piezoelectric layer extending over the first electrode and the reflector as viewed from the cross-sectional plane of the resonator, the piezoelectric layer having a top side and a bottom side as viewed from the cross-sectional plane of the resonator;
• a second electrode extending over the piezoelectric layer, the first electrode and the reflector as viewed from the cross-sectional plane of the resonator;
• a temperature compensation layer (TCL) embedded between the first electrode and the piezoelectric layer only, the second electrode and the piezoelectric layer only, or both of the first and second electrodes and the piezoelectric layer;
• a portion of the TCL and a portion of the piezoelectric layer defining a via through the TCL and the piezoelectric layer to the first electrode as viewed from the cross-sectional plane of the resonator;
• and
• a top metal coupled to the first electrode through the via in the TCL and the piezoelectric layer.