Acoustic resonator devices, filters, and methods are disclosed. An acoustic resonator includes a substrate, a piezoelectric plate having front and back surfaces, and an acoustic Bragg reflector between a surface of the substrate and the back surface of the piezoelectric plate. An interdigital transducer (IDT) is formed on the front surface of the piezoelectric plate. The IDT is configured to excite a shear primary acoustic mode in the piezoelectric plate in response to a radio frequency signal applied to the IDT. At least one finger of the IDT is disposed in a groove in the piezoelectric plate.