Acoustic resonator comprising collar, frame and perimeter distributed bragg reflector
First Claim
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1. A bulk acoustic wave (BAW) resonator, comprising:
- a bottom electrode disposed over a substrate;
a piezoelectric layer disposed over the bottom electrode;
a top electrode disposed over the piezoelectric layer, wherein an overlap of the bottom electrode, the piezoelectric layer and the top electrode defines a main membrane region of the acoustic resonator structure;
a cavity disposed beneath the bottom electrode;
an acoustic reflector disposed over the substrate, and adjacent to the cavity, the acoustic reflector comprising a layer of low acoustic impedance material stacked over a layer of high acoustic impedance material, wherein a thickness of the acoustic reflector is substantially the same as a depth of the cavity, or greater than the depth of the cavity; and
a planarization layer disposed over a portion of the acoustic reflector, and adjacent to the bottom electrode.
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Abstract
An acoustic resonator includes a bottom electrode disposed over a substrate, a piezoelectric layer disposed over the bottom electrode, a top electrode disposed over the piezoelectric layer, and a cavity disposed beneath the bottom electrode. An overlap of the bottom electrode, the piezoelectric layer and the top electrode defines a main membrane region of the acoustic resonator structure. The acoustic resonator further includes an acoustic reflector disposed over the substrate adjacent to the cavity, the acoustic reflector including a layer of low acoustic impedance material stacked on a layer of high acoustic impedance material.
76 Citations
31 Claims
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1. A bulk acoustic wave (BAW) resonator, comprising:
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a bottom electrode disposed over a substrate; a piezoelectric layer disposed over the bottom electrode; a top electrode disposed over the piezoelectric layer, wherein an overlap of the bottom electrode, the piezoelectric layer and the top electrode defines a main membrane region of the acoustic resonator structure; a cavity disposed beneath the bottom electrode; an acoustic reflector disposed over the substrate, and adjacent to the cavity, the acoustic reflector comprising a layer of low acoustic impedance material stacked over a layer of high acoustic impedance material, wherein a thickness of the acoustic reflector is substantially the same as a depth of the cavity, or greater than the depth of the cavity; and a planarization layer disposed over a portion of the acoustic reflector, and adjacent to the bottom electrode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A bulk acoustic wave (BAW) resonator, comprising:
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an acoustic reflector disposed over a substrate around a perimeter of a cavity, a thickness of the acoustic reflector being substantially the same as a depth of the cavity; a bottom electrode disposed over the acoustic reflector and the cavity; a piezoelectric layer disposed over the bottom electrode; a top electrode disposed over the piezoelectric layer, wherein an overlap of the bottom electrode, the piezoelectric layer and the top electrode defines a main membrane region of the acoustic resonator structure; a frame disposed within the main membrane region and having an outer edge substantially aligned with a boundary of the main membrane region; and a collar disposed outside the main membrane region and having an inner edge substantially aligned with the boundary of or overlapping the main membrane region. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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21. A bulk acoustic wave (BAW) resonator, comprising:
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an acoustic reflector disposed over a substrate around a perimeter of a cavity, the acoustic reflector comprising at least one layer of low acoustic impedance material, a thickness of the acoustic reflector being substantially the same as a depth of the cavity; a bottom electrode disposed over the acoustic reflector and the cavity; a piezoelectric layer disposed over the bottom electrode; a top electrode disposed over the piezoelectric layer, wherein an overlap of the bottom electrode, the piezoelectric layer and the top electrode defines a main membrane region of the acoustic resonator structure; a frame disposed within the main membrane region and having, an outer edge substantially aligned with a boundary of the main membrane region; and a collar disposed outside the main membrane region and having an inner edge substantially aligned with the boundary of or overlapping the main membrane region. - View Dependent Claims (22, 23, 24, 25)
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26. A bulk acoustic wave (BAW) resonator, comprising:
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a bottom electrode disposed over a substrate; a piezoelectric layer disposed over the bottom electrode; a top electrode disposed over the piezoelectric layer, wherein an overlap of the bottom electrode, the piezoelectric layer and the top electrode defines a main membrane region of the acoustic resonator structure; a cavity disposed beneath the bottom electrode; an acoustic reflector disposed over the substrate, and adjacent to the cavity, the acoustic reflector comprising a layer of low acoustic impedance material stacked over a layer of high acoustic impedance material; a frame disposed within the main membrane region and having an outer edge substantially aligned with a boundary of the main membrane region; a collar, separate from the frame, disposed outside the main membrane region, and having an inner edge substantially aligned with the boundary of the main membrane region, or overlapping the main membrane region; and a planarization layer disposed over a portion of the acoustic reflector, and adjacent to the bottom electrode. - View Dependent Claims (27, 28, 29, 30, 31)
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Specification