Transversely-excited film bulk acoustic resonators for high power applications

A filter device, comprising:

• a substrate;
• a single-crystal piezoelectric plate having front and back surfaces, the back surface attached to the surface of the substrate, portions of the single-crystal piezoelectric plate forming one or more diaphragms spanning respective cavities in the substrate;
• and
• a conductor pattern formed on the front surface, the conductor pattern including a plurality of interdigital transducers (IDTs) of a respective plurality of acoustic resonators, interleaved fingers of each of the plurality of IDTs disposed on a diaphragm of the one or more diaphragms, the piezoelectric plate and all of the IDTs configured such that respective radio frequency signals applied to each IDT excite respective shear primary acoustic modes in the respective diaphragms, wherein
• the interleaved fingers of all of the plurality of IDTs have a common finger thickness, which is greater than or equal to 0.85 times a thickness of the piezoelectric plate and less than or equal to 2.5 times the thickness of the piezoelectric plate.

A filter device, comprising:

• a substrate;
• a single-crystal piezoelectric plate having front and back surfaces, the back surface attached to the surface of the substrate, portions of the single-crystal piezoelectric plate forming one or more diaphragms spanning respective cavities in the substrate;
• a conductor pattern formed on the front surface, the conductor pattern including a plurality of interdigital transducers (IDTs) of a respective plurality of acoustic resonators, interleaved fingers of each of the plurality of IDTs disposed on a diaphragm of the one or more diaphragms, the plurality of resonators including one or more shunt resonators and one or more series resonators;
• a first dielectric layer having a first thickness deposited between the fingers of the IDTs of the one or more shunt resonators;
• and
• a second dielectric layer having a second thickness deposited between the fingers of the IDTs of the one or more series resonators, wherein
• the second thickness is less than the first thickness and greater than or equal to zero, and
• the interleaved fingers of all of the plurality of IDTs have a common finger thickness, which is greater than or equal to 0.875 times a thickness of the piezoelectric plate and less than 2.25 times the thickness of the piezoelectric plate.