Acoustic resonator device

An acoustic resonator device comprising:

• a substrate;
• a piezoelectric layer attached either directly or via one or more intermediate layers to the substrate;
• a cavity between the piezoelectric layer and the substrate;
• and
• an interdigital transducer (IDT) at a surface of the piezoelectric layer and having a pair of busbars with a plurality of interleaved fingers extending therefrom,
• wherein a respective side of at least one finger of the plurality of interleaved fingers extends from a respective busbar of the pair of busbars at an oblique angle to at least a portion of an edge of the cavity, wherein the oblique angle is neither normal nor parallel.

A filter device comprising:

• a plurality of acoustic resonators that each comprise:
• a substrate;
• a piezoelectric layer attached either directly or via one or more intermediate layers to the substrate and including a portion that forms a diaphragm over a cavity;
• an interdigital transducer (IDT) at a surface of the piezoelectric layer and having a pair of busbars with a plurality of interleaved fingers extending therefrom,
• wherein the IDT of each of the plurality of acoustic resonators is configured to excite a primarily shear acoustic mode in the respective diaphragm in response to a radio frequency signal applied to the IDT,
• wherein the primarily shear acoustic mode excites a bulk shear wave that propagates in a direction substantially normal to the surface of the respective piezoelectric layer and that is transverse to a primarily lateral direction of an electric field created by the plurality of interleaved fingers of the respective IDT, and
• wherein a respective side of at least one finger of the plurality of interleaved fingers of at least one of the plurality of acoustic resonators extends from a respective busbar of the pair of busbars at an oblique angle to a portion of a perimeter of the cavity.