Method of making tunable thin film acoustic resonators
AssigneeAgilent Technologies, Inc.
InventorsRichard C. Ruby, Paul Philip Merchant
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Abstract
An acoustical resonator comprising top and bottom electrodes that sandwich a PZ layer. The resonance frequency of the acoustical resonator may be adjusted after fabrication by utilizing heating elements included in the acoustical resonator and/or by adjusting the thickness of a tuning layer. In the preferred embodiment of the present invention, the electrodes comprise Mo layers. One embodiment of the present invention is constructed on a Si3N4 membrane. A second embodiment of the present invention is constructed such that it is suspended over a substrate on metallic columns. In the preferred embodiment, the electrodes are deposited by a method that minimizes the stress in the electrodes.
Claims2
A method for fabricating an acoustical resonator comprising the steps of:
- depositing a layer of Si3N4 on the top surface of a silicon substrate having top and bottom surfaces;
- depositing a bottom electrode comprising a metallic layer on said Si3N4 layer;
- depositing a PZ layer on said metallic layer;
- depositing a top electrode comprising a metallic layer on said PZ layer;
- etching said silicon substrate to remove the portion thereof between said bottom surface and a portion of said Si3N4, wherein either said bottom or said top metallic layer comprises a metal chosen from the group consisting of Mo, Ti, and W;
- and
- removing a portion of said silicon substrate from said bottom surface prior to depositing said bottom electrode.
A method for fabricating an acoustical resonator comprising the steps of:
- depositing a layer of Si3N4 on the top surface of a silicon substrate having top and bottom surfaces;
- depositing a bottom electrode comprising a metallic layer on said Si3N4 layer;
- depositing a PZ layer on said metallic layer;
- depositing a top electrode comprising a metallic layer on said PZ layer;
- and
- etching said silicon substrate to remove the portion thereof between said bottom surface and a portion of said Si3N4, wherein either said bottom of said top metallic layer comprises a metal chosen from the group consisting of Mo, Ti, and W;
- wherein the deposition conditions for depositing one of said metallic layers are determined by measuring the deflection of a silicon substrate after a metallic layer is deposited thereon using said deposition conditions.
Dependencies are inferred from the claim text.