BAW resonator having lateral energy confinement and methods of fabrication thereof
DCFirst Claim
1. A Bulk Acoustic Wave (BAW) resonator, comprising:
- a piezoelectric layer;
a first electrode on a first surface of the piezoelectric layer;
a second electrode on a second surface of the piezoelectric layer opposite the first electrode on the first surface of the piezoelectric layer;
a passivation layer on a surface of the second electrode opposite the piezoelectric layer within an active region of the BAW resonator, the passivation layer having a thickness (TPA) within the active region of the BAW resonator; and
one or more material layers on the second surface of the piezoelectric layer adjacent to the second electrode in an outer region of the BAW resonator, the outer region of the BAW resonator being a region outside of the active region of the BAW resonator and the one or more material layers having a thickness that is n times the thickness (TPA) of the passivation layer within the active region, wherein;
n is a value other than 1; and
n is within a range of values for which a density of mechanical energy in the outer region of the BAW resonator is reduced as compared to a density of mechanical energy in the outer region of the BAW resonator when n is equal to 1.
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Abstract
Embodiments of a Bulk Acoustic Wave (BAW) resonator in which an outer region of the BAW resonator is engineered in such a manner that lateral leakage of mechanical energy from an active region of the BAW resonator is reduced, and methods of fabrication thereof, are disclosed. In some embodiments, a BAW resonator includes a piezoelectric layer, a first electrode on a first surface of the piezoelectric layer, a second electrode on a second surface of the piezoelectric layer opposite the first electrode, and a passivation layer on a surface of the second electrode opposite the piezoelectric layer, the passivation layer having a thickness (TPA). The BAW resonator also includes a material on the second surface of the piezoelectric layer adjacent to the second electrode in an outer region of the BAW resonator. The additional material has a thickness that is n times the thickness (TPA) of the passivation layer.
9 Citations
18 Claims
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1. A Bulk Acoustic Wave (BAW) resonator, comprising:
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a piezoelectric layer; a first electrode on a first surface of the piezoelectric layer; a second electrode on a second surface of the piezoelectric layer opposite the first electrode on the first surface of the piezoelectric layer; a passivation layer on a surface of the second electrode opposite the piezoelectric layer within an active region of the BAW resonator, the passivation layer having a thickness (TPA) within the active region of the BAW resonator; and one or more material layers on the second surface of the piezoelectric layer adjacent to the second electrode in an outer region of the BAW resonator, the outer region of the BAW resonator being a region outside of the active region of the BAW resonator and the one or more material layers having a thickness that is n times the thickness (TPA) of the passivation layer within the active region, wherein; n is a value other than 1; and n is within a range of values for which a density of mechanical energy in the outer region of the BAW resonator is reduced as compared to a density of mechanical energy in the outer region of the BAW resonator when n is equal to 1. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A BAW resonator comprising:
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a piezoelectric layer; a first electrode on a first surface of the piezoelectric layer; a second electrode on a second surface of the piezoelectric layer opposite the first electrode on the first surface of the piezoelectric layer; a passivation layer on a surface of the second electrode opposite the piezoelectric layer within an active region of the BAW resonator, the passivation layer having a thickness (TPA) within the active region of the BAW resonator; and one or more material layers on the second surface of the piezoelectric layer adjacent to the second electrode in an outer region of the BAW resonator, the outer region of the BAW resonator being a region outside of the active region of the BAW resonator and the one or more material layers having a thickness that is n times the thickness (TPA) of the passivation layer within the active region, wherein; n is a value other than 1; and n is such that the outer region of the BAW resonator and the active region of the BAW resonator are acoustically matched in such a manner that one or more wavelengths that cause energy leakage into the outer region are not excited in the active region.
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10. A method of fabricating a BAW resonator, comprising:
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providing an initial structure comprising a piezoelectric layer and a first electrode on a first surface of the piezoelectric layer; providing a second electrode on a second surface of the piezoelectric layer opposite the first electrode on the first surface of the piezoelectric layer; providing a passivation layer on a surface of the second electrode opposite the piezoelectric layer within an active region of the BAW resonator, the passivation layer having a thickness (TPA) within the active region of the BAW resonator; and providing one or more material layers on the second surface of the piezoelectric layer adjacent to the second electrode in an outer region of the BAW resonator, the outer region of the BAW resonator being a region outside of the active region of the BAW resonator and the one or more material layers having a thickness that is n times the thickness (TPA) of the passivation layer within the active region, wherein; n is a value other than 1; and n is such that the outer region of the BAW resonator and the active region of the BAW resonator are acoustically matched in such a manner that one or more wavelengths that cause energy leakage into the outer region are not excited in the active region.
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11. A method of fabricating a Bulk Acoustic Wave (BAW) resonator, comprising:
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providing an initial structure comprising a piezoelectric layer and a first electrode on a first surface of the piezoelectric layer; providing a second electrode on a second surface of the piezoelectric layer opposite the first electrode on the first surface of the piezoelectric layer; providing a passivation layer on a surface of the second electrode opposite the piezoelectric layer within an active region of the BAW resonator, the passivation layer having a thickness (TPA) within the active region of the BAW resonator; and providing one or more material layers on the second surface of the piezoelectric layer adjacent to the second electrode in an outer region of the BAW resonator, the outer region of the BAW resonator being a region outside of the active region of the BAW resonator and the one or more material layers having a thickness that is n times the thickness (TPA) of the passivation layer within the active region, wherein; n is a value other than 1; and n is within a range of values for which a density of mechanical energy in the outer region of the BAW resonator is reduced as compared to a density of mechanical energy in the outer region of the BAW resonator when n is equal to 1. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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Specification