US Patent 11271539 Transversely-excited film bulk acoustic resonator with tether-supported diaphragm

An acoustic resonator device includes a substrate and a piezoelectric plate. A first portion of the piezoelectric plate is attached to the substrate. A second portion of the piezoelectric forms a diaphragm suspended over a cavity in the substrate. An interdigital transducer (IDT) is formed on a surface of the piezoelectric plate, the IDT including first and second busbars disposed on the first portion and interleaved IDT fingers disposed on the diaphragm. A plurality of tethers support the diaphragm over the cavity, each tether providing an electrical connection between a corresponding one of the interleaved IDT fingers and one of the first and second busbars.