PROTECTED RESONATOR
First Claim
1. A resonator comprising:
- a substrate;
a piezoelectric layer formed over said substrate a least a portion of the piezoelectric layer being disposed between two electrodes;
a temperature compensating layer surrounding the piezoelectric layer and electrodes;
wherein the piezoelectric material is supported on the substrate by an electrically conductive material structure that electrically interconnects one of contact pads or semiconductor devices on the substrate with the top electrode;
a cap layer formed over, but not in contact with, the piezoelectric material surrounded by the temperature compensating layer.
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Accused Products
Abstract
A bulk acoustic wave resonator structure that isolates the core resonator from both environmental effects and aging effects. The structure has a piezoelectric layer at least partially disposed between two electrodes. The structure is protected against contamination, package leaks, and changes to the piezoelectric material due to external effects while still providing inertial resistance. The structure has one or more protective elements that limit aging effects to at or below a specified threshold. The resonator behavior is stabilized across the entire bandwidth of the resonance, not just at the series resonance. Examples of protective elements include a collar of material around the core resonator so that perimeter and edge-related environmental and aging phenomena are kept away from the core resonator, a Bragg reflector formed above or below the piezoelectric layer and a cap formed over the piezoelectric layer.
8 Citations
21 Claims
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1. A resonator comprising:
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a substrate; a piezoelectric layer formed over said substrate a least a portion of the piezoelectric layer being disposed between two electrodes; a temperature compensating layer surrounding the piezoelectric layer and electrodes;
wherein the piezoelectric material is supported on the substrate by an electrically conductive material structure that electrically interconnects one of contact pads or semiconductor devices on the substrate with the top electrode;a cap layer formed over, but not in contact with, the piezoelectric material surrounded by the temperature compensating layer. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A resonator comprising:
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a substrate; a piezoelectric layer formed over said substrate a least a portion of the piezoelectric layer being disposed between two electrodes; a temperature compensating layer substantially surrounding the piezoelectric layer and electrodes;
wherein the top electrode is electrically interconnected to one of contact pads or semiconductor devices on the substrate through a window in the temperature compensation material and wherein the piezoelectric material is supported on the substrate by a post that is less than completely laterally coextensive with the piezoelectric layer;a cap layer formed over, but not in contact with, the piezoelectric material surrounded by the temperature compensating layer. - View Dependent Claims (8, 9)
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10. A resonator comprising:
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a substrate; a piezoelectric layer formed over said substrate a least a portion of the piezoelectric layer being disposed between two electrodes; a protective element formed over the piezoelectric layer and its associated electrodes wherein the resonator, in operation, has both a parallel resonance and series resonance and wherein the protective element is configured such that the resonator, in operation, exhibits a shift in the impedance response of the resonator as a function of frequency at a rate of about 5 ppm per year or less. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification