Transversely-excited film bulk acoustic resonator with diaphragm support pedestals

A method of fabricating an acoustic resonator device, comprising:

• forming a cavity over a substrate, one or more diaphragm support pedestals disposed within the cavity;
• depositing a bonding layer over the substrate, the cavity, and the one or more diaphragm support pedestals;
• bonding a piezoelectric layer to the bonding layer such that a portion of the piezoelectric layer forms a diaphragm over the cavity with each of the one or more diaphragm support pedestals extending from a bottom surface of the cavity to the bonding layer;
• and
• forming an interdigital transducer (IDT) at the piezoelectric layer such that interleaved fingers of the IDT are disposed on the diaphragm.

A method of fabricating an acoustic resonator device, comprising:

• depositing a bonding layer over a substrate;
• forming a cavity in at least one of the substrate and the bonding layer, one or more diaphragm support pedestals disposed within the cavity;
• bonding a piezoelectric layer to the bonding layer and the one or more diaphragm support pedestals such that a portion of the piezoelectric layer forms a diaphragm over the cavity with each of the one or more diaphragm support pedestals extending from a bottom surface of the cavity to the diaphragm;
• and
• forming an interdigital transducer (IDT) at the piezoelectric layer such that interleaved fingers of the IDT are disposed on the diaphragm.

A filter device comprising:

• a plurality of acoustic resonators that each comprise:
• a substrate,
• a piezoelectric layer attached to the substrate either directly or via one or more intermediate layers and having a portion that forms a diaphragm over a cavity of the respective acoustic resonator,
• an interdigital transducer (IDT) at the piezoelectric layer that includes interleaved fingers on the diaphragm, and
• at least one diaphragm support pedestal that extends from a surface of the cavity to the diaphragm.