Bulk acoustic resonator comprising piezoelectric layer and inverse piezoelectric layer
First Claim
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1. A bulk acoustic wave (BAW) resonator structure, comprising:
- a first electrode disposed over a substrate;
a first piezoelectric layer disposed over the first electrode, the first piezoelectric layer having a first c-axis oriented along a first direction;
a second piezoelectric layer disposed over the first electrode, wherein the second piezoelectric layer has a second c-axis oriented in a second direction that is substantially antiparallel to the first direction; and
a second electrode disposed over the first piezoelectric layer and over the second piezoelectric layer, the second electrode being in direct contact with the first piezoelectric and in direct contact with the second piezoelectric layer.
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Abstract
In a representative embodiment, a bulk acoustic wave (BAW) resonator, comprises: a first electrode disposed over a substrate; a first piezoelectric layer disposed over the first electrode, the first piezoelectric layer having a first c-axis oriented along a first direction; a second electrode disposed over the first piezoelectric layer; and a second piezoelectric layer disposed over the first electrode and adjacent to the first piezoelectric layer, wherein the second piezoelectric layer has a second c-axis oriented in a second direction that is substantially antiparallel to the first direction.
472 Citations
17 Claims
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1. A bulk acoustic wave (BAW) resonator structure, comprising:
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a first electrode disposed over a substrate; a first piezoelectric layer disposed over the first electrode, the first piezoelectric layer having a first c-axis oriented along a first direction; a second piezoelectric layer disposed over the first electrode, wherein the second piezoelectric layer has a second c-axis oriented in a second direction that is substantially antiparallel to the first direction; and a second electrode disposed over the first piezoelectric layer and over the second piezoelectric layer, the second electrode being in direct contact with the first piezoelectric and in direct contact with the second piezoelectric layer. - View Dependent Claims (2, 3, 4)
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5. A bulk acoustic wave (BAW) resonator structure, comprising:
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a first electrode disposed over a substrate; a first piezoelectric layer disposed over the first electrode, the first piezoelectric layer having a first c-axis oriented along a first direction; a second electrode disposed over the first piezoelectric layer; a second piezoelectric layer disposed over the first electrode and adjacent to the first piezoelectric layer, the second piezoelectric layer having a second c-axis oriented along a second direction that is substantially antiparallel to the first direction; a third piezoelectric layer disposed over the second electrode, the third piezoelectric layer having a third c-axis oriented parallel to the first direction; a third electrode disposed over the third piezoelectric layer; a fourth piezoelectric layer disposed over the second electrode and adjacent to the third piezoelectric layer, the second piezoelectric layer having a fourth c-axis oriented parallel to the second direction. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 17)
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15. A bulk acoustic wave (BAW) resonator structure, comprising:
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a first electrode disposed over a substrate; a cavity beneath the first electrode; a first piezoelectric layer disposed over the first electrode, the first piezoelectric layer having a first c-axis oriented along a first direction; a second electrode disposed over the first piezoelectric layer, wherein an active region of the BAW resonator structure comprises an overlap of the first electrode and the second electrode with the cavity; and a second piezoelectric layer disposed over the first electrode and adjacent to the first piezoelectric layer, the second piezoelectric layer having a second c-axis oriented in a second direction that is substantially antiparallel to the first direction, wherein the second electrode overlaps the second piezoelectric layer.
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16. A bulk acoustic wave (BAW) resonator structure, comprising:
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a first electrode disposed over a substrate; a first piezoelectric layer disposed over the first electrode, the first piezoelectric layer having a first c-axis oriented along a first direction; a second electrode disposed over the first piezoelectric layer; and a second piezoelectric layer disposed over the first electrode and adjacent to the first piezoelectric layer, the second piezoelectric layer having a second c-axis oriented in a second direction that is substantially antiparallel to the first direction, wherein the second piezoelectric layer has a piezoelectric coupling coefficient (e33ip) in a range between approximately −
0.1 times a piezoelectric coupling coefficient (e33p) of the first piezoelectric layer and approximately −
2 times a piezoelectric coupling coefficient (e33p) of the first piezoelectric layer.
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Specification