Patent attributes
There is disclosed acoustic resonators and filter devices. An acoustic resonator includes a single-crystal piezoelectric plate having front and back surfaces, a portion of the piezoelectric plate forming a diaphragm. A thickness of the piezoelectric plate is greater than or equal to 300 nm and less than or equal to 500 nm. An interdigital transducer (IDT) is formed on the front surface of the single-crystal piezoelectric plate such that interleaved fingers of the IDT are disposed on the diaphragm. The piezoelectric plate and the IDT are configured such that a radio frequency signal applied to the IDT excites a primary shear acoustic mode in the diaphragm. The interleaved fingers of the IDT are substantially molybdenum. The diaphragm is contiguous with the piezoelectric plate around at least 50% of the IDT.