Abstract: A bulk acoustic wave resonator includes a substrate, a first electrode, wherein a cavity is formed between the substrate and the first electrode, a piezoelectric layer disposed on the first electrode and overlapping at least a portion of the first electrode, a second electrode disposed on the piezoelectric layer and overlapping at least a portion of the piezoelectric layer, a passivation layer having at least a portion disposed on the second electrode and overlapping at least a portion of the second electrode, and a lower frame spaced apart from the substrate and having a portion of the cavity disposed therebetween. Any one of the second electrode and the passivation layer includes a protruding portion having a first thickness and an extended portion having a second thickness less than the first thickness, and an inner end of the lower frame and an end of the protruding portion are spaced apart horizontally.

Abstract: A bulk acoustic resonator includes: a substrate including an upper surface on which a substrate protection layer is disposed; and a membrane layer forming a cavity together with the substrate, wherein a thickness deviation of either one or both of the substrate protection layer and the membrane layer is 170 ? or less.

Abstract: A bulk-acoustic wave resonator includes: a substrate; and a resonator portion in which a first electrode, a piezoelectric layer, and a second electrode are sequentially stacked on the substrate. The piezoelectric layer is formed of aluminum nitride (AlN) containing scandium (Sc). The bulk-acoustic wave resonator satisfies the following expression: leakage current density×scandium (Sc) content<20. The leakage current density is a leakage current density of the piezoelectric layer in ?A/cm2, and the scandium (Sc) content is a weight percentage (wt %) of scandium (Sc) in the piezoelectric layer.

Abstract: A bulk-acoustic wave resonator includes a resonator, including a first electrode, a piezoelectric layer, and a second electrode sequentially stacked on a substrate; and an insertion layer disposed below the piezoelectric layer, and configured to partially elevate the piezoelectric layer and the second electrode, wherein the insertion layer may be formed of a material containing silicon (Si), oxygen (O), and nitrogen (N).

Abstract: An acoustic resonator includes a substrate, a center portion, an extending portion, and a barrier layer. A first electrode, a piezoelectric layer, and a second electrode are sequentially stacked on the substrate in the central portion. The extending portion is configured to extend from the center portion, and includes an insertion layer disposed below the piezoelectric layer. The barrier layer is disposed between the first electrode and the piezoelectric layer.

Abstract: A bulk acoustic resonator includes: a substrate; a first electrode disposed on the substrate; a piezoelectric layer disposed to cover at least a portion of the first electrode; a second electrode disposed to cover at least a portion of the piezoelectric layer; a metal pad connected to the first electrode and the second electrode; and a protective layer disposed to cover at least the metal pad.

Abstract: A bulk-acoustic wave resonator includes: a first electrode disposed above a substrate; a piezoelectric layer disposed to cover at least a portion of the first electrode; and a second electrode disposed to cover at least a portion of the piezoelectric layer. A plurality of steps are formed in any one or any combination of any two or more of the first electrode, the piezoelectric layer, and the second electrode in an active region in which the first electrode, the piezoelectric layer, and the second electrode are all disposed to overlap one another.

Abstract: A bulk-acoustic wave resonator includes a substrate; a lower electrode formed on the substrate, and at least a portion of the lower electrode is formed on a cavity; a piezoelectric layer formed on the lower electrode; an upper electrode formed on the piezoelectric layer; a membrane layer formed below the lower electrode and forming the cavity together with the substrate; and a protruding portion formed on the membrane layer and further formed in the cavity in a direction that extends away from the membrane layer.

Abstract: A bulk acoustic wave resonator includes a substrate; a lower electrode disposed on the substrate; a piezoelectric layer disposed to cover at least a portion of the lower electrode; an upper electrode disposed to cover at least a portion of the piezoelectric layer; and a passivation layer disposed to cover at least a portion of the upper electrode, wherein the passivation layer includes a non-trimming-processed portion disposed outside an active region of the bulk acoustic wave resonator in which portions of the lower electrode, the piezoelectric layer, and the upper electrode overlap, and having a thickness that is thicker than a thickness of a portion of the passivation layer disposed in the active region.

Abstract: A bulk-acoustic wave resonator includes a substrate, a cavity formed in the substrate, a first electrode, a piezoelectric layer, and a second electrode stacked in order on the substrate, a resonator defined by the first electrode, the piezoelectric layer, and the second electrode overlapping in a vertical direction in an upper portion of the cavity, an additional layer disposed on one surface of the first electrode arranged in a wiring region on an external side of the resonator, and a wiring electrode connected to the first electrode arranged in the wiring region. The first electrode forms a contact interfacial surface with the additional layer and the wiring electrode.

Abstract: A bulk acoustic resonator includes: a substrate; a first electrode disposed on the substrate; a piezoelectric layer disposed to cover at least a portion of the first electrode; a second electrode disposed to cover at least a portion of the piezoelectric layer; and an insertion layer disposed below a partial region of the piezoelectric layer. A thickness of the first electrode in an active region in which the first electrode, the piezoelectric layer, and the second electrode overlap one another is less than a thickness of a region outside the active region. An angle of inclination of an internal side surface of the insertion layer is different from an angle of inclination of an external side surface of the insertion layer.

Abstract: A bulk-acoustic wave resonator includes: a resonator comprising a central portion in which a first electrode, a piezoelectric layer, and a second electrode are sequentially stacked on a substrate, and an extension portion disposed along a periphery of the central portion; and an insertion layer disposed below the piezoelectric layer in the extension portion to raise the piezoelectric layer. The insertion layer may have a first inclined surface formed along a side surface facing the central portion, and the first electrode may have a second inclined surface extending from a lower end of the first inclined surface of the insertion layer.

Abstract: A bulk acoustic wave resonator includes a membrane layer, together with a substrate, forming a cavity, a lower electrode disposed on the membrane layer, a piezoelectric layer disposed on a flat surface of the lower electrode and an upper electrode covering a portion of the piezoelectric layer. An overall region at a side of the piezoelectric layer is exposed to the air. The side of the piezoelectric layer has a gradient of 65° to 90° with respect to a top surface of the lower electrode.

Abstract: A bulk-acoustic wave resonator includes a substrate; a membrane layer forming a cavity with the substrate; a first electrode at least partially disposed on an upper portion of the cavity including an end portion that is thicker than other portions of the first electrode; an insertion layer including a first portion disposed adjacent to from the end portion of the first electrode and a second portion disposed on an upper portion of the first electrode; a piezoelectric layer disposed to cover the insertion layer; and a second electrode disposed on an upper portion of the piezoelectric layer.

Abstract: An acoustic resonator includes: a central portion; an extension portion extended outwardly of the central portion; a first electrode, a piezoelectric layer, and a second electrode sequentially stacked on a substrate, in the central portion; and an insertion layer disposed below the piezoelectric layer in the extension portion, wherein the piezoelectric layer includes a piezoelectric portion disposed in the central portion, and a bent portion disposed in the extension portion and extended from the piezoelectric portion at an incline depending on a shape of the insertion layer.

Abstract: An acoustic wave resonator includes a resonating part disposed on and spaced apart from a substrate by a cavity, the resonating part including a membrane layer, a first electrode, a piezoelectric layer, and a second electrode that are sequentially stacked. 0 ???Mg?170 ? may be satisfied, ?Mg being a difference between a maximum thickness and a minimum thickness of the membrane layer disposed in the cavity.

Abstract: An acoustic wave resonator includes a resonating part disposed on and spaced apart from a substrate by a cavity, the resonating part including a membrane layer, a first electrode, a piezoelectric layer, and a second electrode that are sequentially stacked. 0 ???Mg?170 ? may be satisfied, ?Mg being a difference between a maximum thickness and a minimum thickness of the membrane layer disposed in the cavity.

Abstract: A bulk acoustic resonator includes: a substrate including an upper surface on which a substrate protection layer is disposed; and a membrane layer forming a cavity together with the substrate, wherein a thickness deviation of either one or both of the substrate protection layer and the membrane layer is 170 ? or less.

Abstract: A bulk-acoustic wave resonator includes: a membrane layer disposed on a substrate and forming a cavity; a lower electrode disposed on the membrane layer; a piezoelectric layer disposed on the lower electrode; an upper electrode disposed on the piezoelectric layer, and including a frame part disposed at an edge of an active area and having a thickness greater than that of a portion of the upper electrode disposed in a central portion of the active area; and a frequency adjusting layer disposed on the piezoelectric layer and the upper electrode. The frequency adjusting layer is excluded from an inclined surface of the frame part, or a thickness of a portion of the frequency adjusting layer on the inclined surface is less than that of other portions of the frequency adjusting layer. The frequency adjusting layer is disposed on a portion of the piezoelectric layer protruding from the upper electrode.

Abstract: A bulk acoustic wave resonator includes a substrate including a first via and a second via, a lower electrode connection member, a lower electrode, a piezoelectric layer, an upper electrode, and an upper electrode connection member spaced apart from the lower electrode connection member. The lower electrode, the piezoelectric layer, and the upper electrode constitute a resonant portion. The lower electrode connection member electrically connects the lower electrode to the first via and supports a first edge portion of the resonant portion. The upper electrode connection member electrically connects the upper electrode to the second via and supports a second edge portion of the resonant portion. Either one or both of the upper electrode connection member and the lower electrode connection member includes a respective extension portion connected to a respective one of the first via and the second via that is disposed below the resonant portion.