Thin film bulk acoustic resonator filters with a piezoelectric layer of lead scandium tantalum oxide
First Claim
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1. An electric filter comprising a plurality of thin film bulk acoustic resonators (FBARs) linked in a series/parallel arrangement wherein:
- each resonator is made up of a thin piezoelectric layer made of a piezoelectric material and sandwiched between two metal electrodes, and other layers of materials;
the thicknesses of the non-piezoelectric layers in the FBARs in the filter are varied one-from another;
the filter has two close-in rejections, at least one of which is deeper as compared with a case where the thicknesses of respective layers in the FBARs are the same among all the FBARs; and
the piezoelectric material is substantially lead scandium tantalum oxide.
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Abstract
An electric filter comprises a plurality of thin film bulk acoustic resonators arranged in series and in parallel which have different thicknesses of one or more non-piezoelectric layers, for example top electrode.
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Citations
48 Claims
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1. An electric filter comprising a plurality of thin film bulk acoustic resonators (FBARs) linked in a series/parallel arrangement wherein:
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each resonator is made up of a thin piezoelectric layer made of a piezoelectric material and sandwiched between two metal electrodes, and other layers of materials;
the thicknesses of the non-piezoelectric layers in the FBARs in the filter are varied one-from another;
the filter has two close-in rejections, at least one of which is deeper as compared with a case where the thicknesses of respective layers in the FBARs are the same among all the FBARs; and
the piezoelectric material is substantially lead scandium tantalum oxide. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. An electric filter comprising at least one FBAR in series and at least one FBAR in parallel, each FBAR having a piezoelectric layer made of a piezoelectric material and sandwiched between two electrodes, wherein:
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the thicknesses of one or more non-piezoelectric layers in the series FBAR are different from those in the parallel FRAR;
the filter has a lower minimum insertion loss in a band pass area as compared with a case where the thicknesses of respective layers in the FBARs are the same among all the FBARs; and
the piezoelectric material is substantially lead scandium tantalum oxide. - View Dependent Claims (22, 23, 24)
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25. An electric filter comprising at least one FBAR in series and at least one FBAR in parallel, each FBAR having a piezoelectric layer made of a piezoelectric material and sandwiched between two electrodes wherein:
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the thicknesses of one or more non-piezoelectric layers in the series FBAR are different from those in the parallel FBAR;
the filter has two close-in rejections, at least one of which is deeper as compared with a case where the thicknesses of respective layers in the FBARs are the same among all the FBARs; and
the piezoelectric material is substantially lead scandium tantalum oxide. - View Dependent Claims (26, 27, 28)
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29. An electric filter comprising a plurality of thin film bulk acoustic resonators (FBARs) linked in a series/parallel arrangement wherein:
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each resonator is made up of a thin piezoelectric layer made of a piezoelectric material and sandwiched between two metal electrodes, and other layers of materials;
the thicknesses of the non-piezoelectric layers in the FBARs in the filter are varied one from another;
the filter has a lower minimum insertion loss in a band pass area as compared with a case where the thicknesses of respective layers in the FBARs are the same among all the FBARs; and
the piezoelectric material is substantially lead scandium tantalum oxide. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48)
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Specification