Abstract: A piezoelectric thin film filter includes: a substrate comprising a parallel cavity constituting the parallel resonator and a series cavity constituting the series resonator; a parallel lower electrode formed on a parallel substrate portion constituting the parallel resonator in the substrate; a series lower electrode formed on a series substrate portion constituting the series resonator in the substrate; a piezoelectric layer formed on the substrate, the parallel lower electrode, and the series lower electrode; and an upper electrode formed on the piezoelectric layer, wherein the series lower electrode comprises a first series lower electrode formed on a portion where the series cavity is formed in the series substrate portion, and a second series lower electrode formed on a portion where the series cavity is not formed in the series substrate portion, wherein a thickness of the first series lower electrode is less than or equal to a predetermined thickness.

Abstract: An air-gap type film bulk acoustic resonator (FBAR) according to the present invention may include: a substrate comprising an air gap portion on an upper surface thereof; a lower electrode formed on the substrate; a piezoelectric layer formed on the lower electrode; an upper electrode formed on the piezoelectric layer; a protective layer formed on the upper electrode; and a beam structure extended in a dome shape from one side of the upper electrode to define a space portion between the upper electrode and the piezoelectric layer, wherein one end of the beam structure is in contact with the piezoelectric layer.

Abstract: An air-gap type film bulk acoustic resonator (FBAR) is provided. The air-gap type FBAR includes a substrate which comprises an air gap portion having a substrate cavity formed in a top surface, a lower electrode formed on the substrate, a piezoelectric layer which is formed on the lower electrode and has one side forming an edge portion in the vicinity of a virtual edge according to vertical projection of the air gap portion, an upper electrode formed on the piezoelectric layer, a first electrode frame which comprises an open ring structure in plane, the open ring structure surrounding a part of a periphery of the piezoelectric layer on the lower electrode, and a second electrode frame positioned on the upper electrode and adjacent to an open portion of the open ring structure.

Abstract: Disclosed is an air-gap type film bulk acoustic resonator (FBAR) including a substrate including an air-gap portion with a top surface in which a substrate cavity is formed, a lower electrode formed above the substrate while surrounding the air-gap portion, a piezoelectric layer formed above the lower electrode, and an upper electrode formed above the piezoelectric layer corresponding to a virtual area formed according to a vertical projection of the air-gap portion. Here, the piezoelectric layer includes a void portion having a piezoelectric cavity between the lower electrode and the upper electrode, and the void portion is formed below an edge portion corresponding to an end part of the upper electrode.

Abstract: An air-gap type film bulk acoustic resonator (FBAR) according to the present invention may include: a substrate comprising an air gap portion on an upper surface thereof; a lower electrode formed on the substrate; a piezoelectric layer formed on the lower electrode; an upper electrode formed on the piezoelectric layer; a protective layer formed on the upper electrode; and a beam structure extended in a dome shape from one side of the upper electrode to define a space portion between the upper electrode and the piezoelectric layer, wherein one end of the beam structure is in contact with the piezoelectric layer.

Abstract: Disclosed is an air-gap type film bulk acoustic resonator (FBAR) including a substrate including an air-gap portion which has a substrate cavity and is formed in a top surface, a lower electrode formed above the substrate, a piezoelectric layer formed above the lower electrode, and an upper electrode formed above the piezoelectric layer and having one side on which an electrode edge is formed to be adjacent to a vertical virtual boundary of a sidewall of the air-gap portion. Here, the piezoelectric layer includes a piezoelectric cavity formed below the electrode edge.

Abstract: An air-gap type film bulk acoustic resonator (FBAR) is provided. The air-gap type FBAR includes a substrate which comprises an air gap portion having a substrate cavity formed in a top surface, a lower electrode formed on the substrate, a piezoelectric layer which is formed on the lower electrode and has one side forming an edge portion in the vicinity of a virtual edge according to vertical projection of the air gap portion, an upper electrode formed on the piezoelectric layer, a first electrode frame which comprises an open ring structure in plane, the open ring structure surrounding a part of a periphery of the piezoelectric layer on the lower electrode, and a second electrode frame positioned on the upper electrode and adjacent to an open portion of the open ring structure.

Abstract: Disclosed is an air-gap type film bulk acoustic resonator (FBAR) including a substrate including an air-gap portion with a top surface in which a substrate cavity is formed, a lower electrode formed above the substrate while surrounding the air-gap portion, a piezoelectric layer formed above the lower electrode, and an upper electrode formed above the piezoelectric layer corresponding to a virtual area formed according to a vertical projection of the air-gap portion. Here, the piezoelectric layer includes a void portion having a piezoelectric cavity between the lower electrode and the upper electrode, and the void portion is formed below an edge portion corresponding to an end part of the upper electrode.

Abstract: A piezoelectric thin film resonator includes: a wafer; a lower electrode positioned on top of the wafer; a piezoelectric layer positioned on top of the lower electrode; and an upper electrode positioned on top of the piezoelectric layer, wherein the upper electrode has concavo-convex patterns formed on top thereof in such a manner as to surround a resonance area formed thereon.