Abstract: A bulk-acoustic wave resonator includes: a substrate; a lower electrode disposed on the substrate; a piezoelectric layer at least partially covering the lower electrode; and an upper electrode at least partially covering the piezoelectric layer. On a surface of the bulk-acoustic wave resonator, a centroid of an active area in which the lower electrode, the piezoelectric layer, and the upper electrode all overlap each other is aligned with a center of a rectangle defining an aspect ratio of the active area. The active area has a shape of a polygon symmetrical with respect to at least one axis passing through the center of the rectangle defining the aspect ratio. The aspect ratio is greater than or equal to 2 and less than or equal to 10.

Abstract: An acoustic resonator includes: a resonating unit including a resonating unit including a piezoelectric layer and first and second electrodes disposed on a lower side and an upper side of the piezoelectric layer, respectively; a substrate disposed on a lower side of the resonating unit; a support unit providing a cavity between the substrate and the resonating unit; and an intermediate metal layer separated from the second electrode and disposed in the resonating unit such that at least a portion thereof is surrounded by the piezoelectric layer and the second electrode.

Abstract: An acoustic resonator includes: a substrate; a resonant region including a first electrode, a piezoelectric layer, and a second electrode disposed on the substrate, and a reflective layer disposed along a periphery of the resonant region; and a connection electrode extending from the second electrode. The reflective layer includes a second section disposed between the resonant region and the connection electrode, and a first section, and a cross-sectional area of the first section is different than a cross-sectional area of the second section.

Abstract: A bulk-acoustic wave resonator includes: a substrate; a membrane layer forming a cavity with the substrate; a lower electrode disposed on the membrane layer; an insertion layer disposed to cover at least a portion of the lower electrode; a piezoelectric layer disposed on the lower electrode to cover the insertion layer; and an upper electrode at least partially disposed on the piezoelectric layer, wherein the upper electrode includes a reflection groove disposed on the insertion layer.

Abstract: A bulk-acoustic wave resonator includes: a first electrode; a piezoelectric layer at least partially disposed on an upper portion of the first electrode; and a second electrode disposed to cover at least a portion of the piezoelectric layer. The second electrode includes a frame disposed at an edge of an active region of the bulk-acoustic wave resonator, and the first electrode, the piezoelectric layer and the second electrode are disposed to overlap one another at the edge of the active region. The frame includes a wall disposed at the edge of the active region and a trench formed on an internal side of the wall. An internal boundary line of the trench has a concave-convex shape in a plane parallel to an upper surface of the frame.

Abstract: An acoustic resonator includes: a resonating unit including a piezoelectric layer, a first electrode disposed on a lower side of the piezoelectric layer, and a second electrode disposed on an upper side of the piezoelectric layer; a substrate disposed below the resonating unit; a support unit forming a cavity between the substrate and the resonating unit; and a pillar extending through the cavity and connecting the resonating unit to the substrate. The resonating unit further includes a first insertion layer disposed above the pillar.

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 is provided. The resonator includes a substrate; a resonant portion including a first electrode, a piezoelectric layer, and a second electrode sequentially stacked on the substrate; and a temperature compensation layer disposed at least one of above and below the piezoelectric layer, wherein a material of the temperature compensation layer has a coefficient of thermal expansion of which a sign is opposite to a sign of a coefficient of thermal expansion of a material of the piezoelectric layer, and wherein a relation of a thickness of the temperature compensation layer and a thickness of the piezoelectric layer satisfies the following equation: 0.25<Thickness of Temperature Compensation Layer/Thickness of Piezoelectric Layer<0.33.

Abstract: A bulk acoustic wave resonator includes: a substrate; a resonant portion including a sequentially stacked first electrode, piezoelectric layer, and second electrode; a cavity defined between the substrate and the resonant portion; and a heat dissipation portion disposed in the cavity and supporting the resonant portion. The second electrode includes a first region and a second region having a thickness greater than a thickness of the first region, and the second region is disposed above the heat dissipation portion.

Abstract: A bulk-acoustic wave 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 connection member connected an upper surface of the metal pad. A lower end portion of the connection member includes a tapered portion decreasing in a diameter in a direction toward a lower end of the connection member, and an angle between an inclined surface of the tapered portion and the upper surface of the metal pad is 45° to 80°.

Abstract: A bulk-acoustic wave resonator includes: a first electrode; a piezoelectric layer at least partially disposed on an upper portion of the first electrode; and a second electrode disposed to cover at least a portion of the piezoelectric layer. The second electrode includes a frame disposed at an edge of an active region of the bulk-acoustic wave resonator, and the first electrode, the piezoelectric layer and the second electrode are disposed to overlap one another at the edge of the active region. The frame includes a wall disposed at the edge of the active region and a trench formed on an internal side of the wall. An internal boundary line of the trench has a concave-convex shape in a plane parallel to an upper surface of the frame.

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 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 connection member connected an upper surface of the metal pad. A lower end portion of the connection member includes a tapered portion decreasing in a diameter in a direction toward a lower end of the connection member, and an angle between an inclined surface of the tapered portion and the upper surface of the metal pad is 45° to 80°.

Abstract: A bulk-acoustic wave resonator includes: a first substrate formed of a first material; an insulating layer or a piezoelectric layer disposed on a first side of the first substrate; and a second substrate formed of a second material and disposed on a second side of the first substrate, wherein the second material has thermal conductivity that is higher than a thermal conductivity of the first material.

Abstract: A bulk-acoustic wave resonator includes: a substrate; a lower electrode disposed on the substrate; a piezoelectric layer at least partially covering the lower electrode; and an upper electrode at least partially covering the piezoelectric layer. On a surface of the bulk-acoustic wave resonator, a centroid of an active area in which the lower electrode, the piezoelectric layer, and the upper electrode all overlap each other is aligned with a center of a rectangle defining an aspect ratio of the active area. The active area has a shape of a polygon symmetrical with respect to at least one axis passing through the center of the rectangle defining the aspect ratio. The aspect ratio is greater than or equal to 2 and less than or equal to 10.

Abstract: An acoustic resonator includes a resonant portion including a piezoelectric layer disposed between a first electrode and a second electrode, and a frame portion disposed along an outer edge of the second electrode. The frame portion includes three reflective portions reflecting lateral waves generated in the resonant portion.

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 filter device includes resonance portions, first and second metal pads. The resonance portions each includes a lower electrode disposed on a substrate, a piezoelectric layer disposed on at least a portion of the lower electrode, and an upper electrode disposed on at least a portion of the piezoelectric layer. The first metal pads are connected to one of the upper electrode and the lower electrode of a corresponding resonance portion among the resonance portions. The second metal pads are disposed outwardly of an active region and connected to the other one of the upper electrode and the lower electrode of adjacent resonant portions among the resonance portions. A ring portion is disposed outwardly of the active region in which the lower electrode, the piezoelectric layer, and the upper electrode overlap is disposed only on a portion of any one of the first and second metal pads.

Abstract: An acoustic resonator includes: a resonating unit including a piezoelectric layer, a first electrode disposed on a lower side of the piezoelectric layer, and a second electrode disposed on an upper side of the piezoelectric layer; a substrate disposed below the resonating unit; a support unit forming a cavity between the substrate and the resonating unit; and a pillar extending through the cavity and connecting the resonating unit to the substrate. The resonating unit further includes a first insertion layer disposed above the pillar.

Abstract: An acoustic resonator includes: a resonating unit including a resonating unit including a piezoelectric layer and first and second electrodes disposed on a lower side and an upper side of the piezoelectric layer, respectively; a substrate disposed on a lower side of the resonating unit; a support unit providing a cavity between the substrate and the resonating unit; and an intermediate metal layer separated from the second electrode and disposed in the resonating unit such that at least a portion thereof is surrounded by the piezoelectric layer and the second electrode.