Bulk acoustic wave resonator

A bulk acoustic wave resonator comprising:

• a substrate;
• a lower electrode connection member disposed on the substrate;
• a lower electrode disposed on the lower electrode connection member;
• a piezoelectric layer disposed on the lower electrode;
• an upper electrode disposed on the piezoelectric layer;
• an upper electrode connection member electrically connecting the upper electrode to the substrate;
• a dielectric layer in which the lower electrode, the piezoelectric layer, and the upper electrode are embedded;
• wherein the dielectric layer is spaced apart from the substrate;
• the lower electrode, the piezoelectric layer, and the upper electrode constitute a resonant portion;
• the bulk acoustic wave resonator further comprises a first extension portion extending from either the lower electrode or the upper electrode to protrude outwardly from the resonant portion;
• a first capacitor portion is constituted by the first extension portion, a portion of the upper electrode connection member disposed above the first extension portion, and a portion of the dielectric layer disposed between the first extension portion and the portion of the upper electrode connection disposed above the first extension portion;
• the bulk acoustic wave resonator further comprises:
• a second extension portion extending from either the lower electrode or the upper electrode to be spaced apart from the first extension portion and protrude outwardly from the resonant portion;
• and
• a second capacitor upper electrode disposed on the dielectric layer above the second extension portion;
• and
• a second capacitor portion is constituted by the second extension portion, the second capacitor upper electrode disposed above the second extension portion, and a portion of the dielectric layer disposed between the second extension portion and the second capacitor upper electrode.

A bulk acoustic wave resonator comprising:

• a substrate;
• a lower electrode connection member disposed on the substrate;
• an upper electrode connection member disposed on the substrate;
• a resonant portion disposed on the lower electrode connection member and comprising:
• a lower electrode disposed on the lower electrode connection member and electrically connected to the lower electrode connection member;
• a piezoelectric layer disposed on the lower electrode;
• and
• an upper electrode disposed on the piezoelectric layer and electrically connected to the upper electrode connection member;
• and
• a dielectric layer covering an upper surface of the resonant portion;
• wherein the dielectric layer is spaced apart from the substrate;
• either the lower electrode comprises an extension portion extending beyond an edge of the piezoelectric layer and an edge of the upper electrode toward the upper electrode connection member, or the upper electrode comprises an extension portion extending beyond an edge of the lower electrode member and an edge of the piezoelectric layer toward the upper electrode connection member;
• the dielectric layer further fills a space between the extension portion and the upper electrode connection member;
• and
• a capacitor portion is constituted by the extension portion, a portion of the upper electrode connection member disposed above the extension portion, and a portion of the dielectric layer disposed between the extension portion and the portion of the upper electrode connection member disposed above the extension portion.