Electrode geometry to minimize stress in transversely-excited film bulk acoustic resonators

An acoustic resonator device comprising:

• a substrate;
• a piezoelectric layer disposed on the substrate and that includes a diaphragm;
• a first pair of interdigital transducer (IDT) busbars that extend along opposing sides of the diaphragm;
• and
• first and second sets of IDT fingers that extend from the first pair of IDT busbars, respectively, with the first and second sets of IDT fingers being interleaved and disposed on the diaphragm,
• wherein the first pair of IDT busbars at least partially overlap the diaphragm in a thickness direction of the acoustic resonator device, and
• wherein at least one interior angle between at least one finger of the first set of IDT fingers and the respective busbar of the first pair of IDT busbars has a rounded corner that is disposed above the diaphragm in a thickness direction of the acoustic resonator device.