Solidly mounted resonator

A solidly mounted resonator, comprising:

• a piezoelectric structure, wherein the piezoelectric structure comprises:
• a lower electrode layer disposed corresponding to a lower portion of the piezoelectric structure, wherein the lower electrode layer comprises:
• a protruding portion protruding downward corresponding to a lower surface of the lower electrode layer;
• a piezoelectric layer disposed on an upper surface of the lower electrode layer;
• an upper electrode layer disposed on an upper surface of the piezoelectric layer,
• a substrate layer disposed below the piezoelectric structure, and
• a laminated structure disposed between the piezoelectric structure and the substrate layer, wherein the laminated structure sequentially comprises:
• a first low acoustic impedance layer, a first high acoustic impedance layer, a second low acoustic impedance layer, a second high acoustic impedance layer, and a third low acoustic impedance layer from bottom to top, wherein the third low acoustic impedance layer is disposed below the piezoelectric layer of the piezoelectric structure,
• wherein the third low acoustic impedance layer comprises:
• a lower electrode slot recessed downward relative to an upper surface of the third low acoustic impedance layer, wherein the lower electrode slot comprises:
• a first groove recessed downward corresponding to an edge of a bottom surface of the lower electrode slot;
• and
• a second groove recessed downward corresponding to a middle portion of the bottom surface of the lower electrode slot.