US 11,146,245 B2 · Mode suppression in acoustic resonators

Abstract

Acoustic resonators, such as bulk acoustic wave (BAW) resonators, are disclosed that include mode suppression structures. Acoustic resonators, including stacked crystal filters (SCFs), are disclosed that include spurious mode suppression by modifying a piezoelectric coupling profile within one or more layers of an SCF. Mode suppression configurations may include structures with one or more inverted polarity piezoelectric layers, one or more non-piezoelectric layers, one or more thicker electrodes of the SCF, and combinations thereof. Symmetric input and output electrical response for SCFs with mode suppression configurations may be exhibited by including piezoelectric materials with different electromechanical coupling values and/or by dividing stress profiles differently by configuring different thicknesses for input and output sides of SCFs.

Claims20

Dependent claims

An acoustic resonator comprising:

a first piezoelectric layer;
a second piezoelectric layer, wherein the first piezoelectric layer has a different thickness than the second piezoelectric layer;
a shared electrode between the first piezoelectric layer and the second piezoelectric layer;
a first electrode on the first piezoelectric layer opposite the shared electrode;
a second electrode on the second piezoelectric layer opposite the shared electrode;
and
a third piezoelectric layer between the second electrode and the shared electrode, the third piezoelectric layer having a polarity that is opposite a polarity of the second piezoelectric layer.

4 more elements

Dependencies are inferred from the claim text.

Mode suppression in acoustic resonators

Life of this patent

Mode suppression in acoustic resonators

Life of this patent

Abstract

Claims20