Abstract: Acoustic resonator devices and filters are disclosed. An acoustic resonator includes a substrate having a surface and a single-crystal piezoelectric plate having parallel front and back surfaces, the back surface attached to the surface of the substrate except for a portion of the piezoelectric plate forming a diaphragm that spans a cavity in the substrate. 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 IDT is configured to excite a primary acoustic mode in the diaphragm in response to a radio frequency signal applied to the IDT. A direction of acoustic energy flow of the primary acoustic mode is substantially orthogonal to the front and back surfaces of the diaphragm. The diaphragm is contiguous with the piezoelectric plate around at least 50% of a periphery of the diaphragm.

Abstract: Acoustic filters, resonators and methods are disclosed. An acoustic filter device includes a substrate having a surface and a single-crystal piezoelectric plate having front and back surfaces, the back surface attached to the surface of the substrate except for a portion of the piezoelectric plate forming a diaphragm that spans a cavity in the substrate. An interdigital transducer is formed on the front surface of the piezoelectric plate with interleaved fingers of the IDT disposed on the diaphragm. At least a portion of a perimeter of the cavity is curved and at least one end zone of the perimeter of the cavity is round.

Abstract: Filter devices are disclosed. A filter device includes a piezoelectric plate comprising a supported portion, a first diaphragm, and a second diaphragm. The supported portion is attached to a substrate and the first and second diaphragms spans respective cavities in the substrate. A first interdigital transducer (IDT) has interleaved fingers on the first diaphragm. A second interdigital transducer (IDT) has interleaved fingers on the second diaphragm. A first dielectric layer is between the interleaved fingers of the first IDT, and a second dielectric layer is between the interleaved fingers of the second IDT. A thickness of the first dielectric layer is greater than a thickness of the second dielectric layer. The piezoelectric plate and the first and second IDTs are configured such that radio frequency signals applied to first and second IDTs excite primary shear acoustic modes in the respective diaphragms.

Abstract: Acoustic resonator devices, filter devices, and methods of fabrication are disclosed. An acoustic resonator includes a substrate having a surface and a single-crystal piezoelectric plate having front and back surfaces. The back surface is attached to the surface of the substrate except for a portion of the piezoelectric plate forming a diaphragm that spans a cavity in the substrate, the diaphragm having an edge about a perimeter of the cavity. 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 IDT is configured to excite a primary acoustic mode in the diaphragm in response to a radio frequency signal applied to the IDT. At least a portion of the edge of the diaphragm is at an oblique angle to the fingers and to an X crystalline axis of the piezoelectric plate.

Abstract: Methods of fabricating acoustic resonators are disclosed. A back surface of a single-crystal piezoelectric plate is bonded to a surface of a substrate. A conductor pattern is formed on the front surface of the piezoelectric plate, the conductor pattern including a plurality of interdigital transducers (IDTs) of a plurality of resonators. A dielectric passivation/tuning layer is formed over the conductor pattern and the front surface of the piezoelectric plate. Electrical measurements are made on at least some of the plurality of resonators. Material is selectively removed from the dielectric passivation/tuning layer in accordance with the electrical measurements.

Abstract: A wide bandwidth time division duplex (TDD) transceiver includes a transmitter, a receiver, and a bandpass filter implemented with a plurality of acoustic resonators including at least one shunt resonator and at least one series resonator. A transmit/receive switch is configured to selectively connect a first terminal of the bandpass filter to either an output of the transmitter or an input of the receiver. Each of the plurality of acoustic resonators is a high power transversely-excite film bulk acoustic resonator.

Abstract: Acoustic resonator devices, filter devices, and methods of fabrication are disclosed. An acoustic resonator includes a substrate having a surface and a single-crystal piezoelectric plate having front and back surfaces. The back surface is attached to the surface of the substrate except for a portion of the piezoelectric plate forming a diaphragm that spans a cavity in the substrate. 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 IDT is configured to excite a primary acoustic mode in the diaphragm in response to a radio frequency signal applied to the IDT. At least a portion of an edge of the diaphragm is at an oblique angle to the fingers.

Abstract: Acoustic resonator devices, filter devices, and methods of fabrication are disclosed. An acoustic resonator includes a substrate having a surface and a single-crystal piezoelectric plate having front and back surfaces. The back surface is attached to the surface of the substrate except for a portion of the piezoelectric plate forming a diaphragm that spans a cavity in the substrate. 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 IDT is configured to excite a primary acoustic mode in the diaphragm in response to a radio frequency signal applied to the IDT. At least a portion of an edge of the diaphragm is at an oblique angle to the fingers. The IDT includes a busbar disposed parallel to the edge of the diaphragm such that the interleaved fingers extend at the oblique angle from the busbar.

Abstract: Acoustic resonator devices and filters are disclosed. An acoustic resonator includes a substrate and a single-crystal piezoelectric plate. A back surface of a supported portion of the piezoelectric plate is attached to a surface of the substrate. A portion of the piezoelectric plate forms a diaphragm that spans a cavity in the substrate. An interdigital transducer (IDT) is formed on a front surface of the piezoelectric plate. The IDT includes first and second busbars, and interleaved fingers extending alternately from the first and second busbars. Overlapping portions of the interleaved fingers are disposed on the diaphragm. At least portions of both the first and second busbars are disposed on the supported portion of the piezoelectric plate. The piezoelectric plate and the IDT are configured such that a radio frequency signal applied to the IDT excites a primary shear acoustic mode within the diaphragm.

Abstract: Filter devices and methods of fabrication are disclosed. A filter device includes a piezoelectric plate attached to a substrate, portions of the piezoelectric plate forming diaphragms spanning respective cavities in the substrate. A conductor pattern formed on a surface of the piezoelectric plate includes a plurality of interdigital transducers (IDTs) of a respective plurality of acoustic resonators including a shunt resonator and a series resonator, interleaved fingers of each of the plurality of IDTs disposed on one of the diaphragms. Radio frequency signals applied to the IDTs excite respective primary shear acoustic modes in the respective diaphragms. A thickness of a first dielectric layer disposed on the front surface between the fingers of the IDT of the shunt resonator is greater than a thickness of a second dielectric layer disposed on the front surface between the fingers of the IDT of the series resonator.

Abstract: Acoustic filters, resonators and methods are disclosed. An acoustic filter device includes a substrate having a surface and a single-crystal piezoelectric plate having front and back surfaces, the back surface attached to the surface of the substrate except for a portion of the piezoelectric plate forming a diaphragm that spans a cavity in the substrate. An interdigital transducer is formed on the front surface of the piezoelectric plate with interleaved fingers of the IDT disposed on the diaphragm. At least a portion of a perimeter of the cavity is curved.

Abstract: Methods of fabricating acoustic resonators are disclosed. A back surface of a single-crystal piezoelectric plate is bonded to a surface of a substrate. A conductor pattern is formed on the front surface of the piezoelectric plate, the conductor pattern including a plurality of interdigital transducers (IDTs) of a plurality of resonators. A dielectric passivation/tuning layer is formed over the conductor pattern and the front surface of the piezoelectric plate. Electrical measurements are made on at least some of the plurality of resonators. Material is selectively removed from the dielectric passivation/tuning layer in accordance with the electrical measurements.

Abstract: Methods of fabricating acoustic resonators are disclosed. A back surface of a piezoelectric plate is bonded to a surface of a substrate. Thickness measurements are made at a plurality of positions on the piezoelectric plate. Excess material is removed from the front surface of the piezoelectric plate in accordance with the thickness measurements to improve a thickness uniformity of the piezoelectric plate. A conductor pattern is formed on the front surface, the conductor pattern including a plurality of interdigital transducers (IDTs) of a plurality of resonators. Cavities are formed in the substrate such that portions of the single-crystal piezoelectric plate form a plurality of diaphragms spanning respective cavities, wherein interleaved fingers of each IDT of the plurality of IDTs are disposed on a respective one of the plurality of diaphragms.

Abstract: Filter devices and methods are disclosed. A filter device includes a substrate having a surface. A back surface of a single-crystal piezoelectric plate is attached to the surface of the substrate, portions of the single-crystal piezoelectric plate forming a plurality of diaphragms spanning respective cavities in the substrate. A conductor pattern is formed on a front surface of the piezoelectric plate, the conductor pattern including a plurality of interdigital transducers (IDTs) of a plurality of resonators. Interleaved fingers of at least a first IDT of the plurality of IDTs are disposed on a diaphragm having a first thickness, and interleaved fingers of at least a second IDT of the plurality of IDTs are disposed on a diaphragm having a second thickness less than the first thickness.

Abstract: Acoustic resonator devices and filters are disclosed. An acoustic resonator includes a substrate having a surface and a single-crystal piezoelectric plate having parallel front and back surfaces, the back surface attached to the surface of the substrate except for a portion of the piezoelectric plate forming a diaphragm that spans a cavity in the substrate. 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 IDT is configured to excite a primary acoustic mode in the diaphragm in response to a radio frequency signal applied to the IDT. A direction of acoustic energy flow of the primary acoustic mode is substantially orthogonal to the front and back surfaces of the diaphragm. The diaphragm is contiguous with the piezoelectric plate around at least 50% of a periphery of the diaphragm.

Abstract: Acoustic resonator devices and filters are disclosed. An acoustic resonator includes a substrate having a surface and a single-crystal piezoelectric plate having parallel front and back surfaces, the back surface attached to the surface of the substrate except for a portion of the piezoelectric plate forming a diaphragm that spans a cavity in the substrate. 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 IDT is configured to excite a primary acoustic mode in the diaphragm in response to a radio frequency signal applied to the IDT. A direction of acoustic energy flow of the primary acoustic mode is substantially orthogonal to the front and back surfaces of the diaphragm. The diaphragm is contiguous with the piezoelectric plate around at least 50% of a perimeter of the cavity.

Abstract: Acoustic resonator devices, filter devices, and methods of fabrication are disclosed. An acoustic resonator includes a substrate having a surface and a single-crystal piezoelectric plate having front and back surfaces. The back surface is attached to the surface of the substrate except for a portion of the piezoelectric plate forming a diaphragm that spans a cavity in the substrate. 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 IDT is configured to excite a primary acoustic mode in the diaphragm in response to a radio frequency signal applied to the IDT. At least a portion of an edge of the diaphragm is at an oblique angle to the fingers.

Abstract: Resonator devices, filter devices, and methods of fabrication are disclosed. A resonator device includes a substrate and a single-crystal piezoelectric plate having parallel front and back surfaces. An acoustic Bragg reflector is sandwiched between a surface of the substrate and the back surface of the single-crystal piezoelectric plate. An interdigital transducer (IDT) is formed on the front surface. The IDT and the single-crystal piezoelectric plate are configured such that a radio frequency signal applied to the IDT excites a shear primary acoustic mode within the single-crystal piezoelectric plate. The acoustic Bragg reflector is configured to reflect the primary shear acoustic mode.

Abstract: Resonator devices, filter devices, and methods of fabrication are disclosed. A resonator device includes a substrate and a single-crystal piezoelectric plate having parallel front and back surfaces. An acoustic Bragg reflector is sandwiched between a surface of the substrate and the back surface of the single-crystal piezoelectric plate. An interdigital transducer (IDT) is formed on the front surface. The IDT is configured to excite shear acoustic waves in the piezoelectric plate in response to a radio frequency signal applied to the IDT.

Abstract: Filter devices and methods of fabrication are disclosed. A filter device includes a piezoelectric plate attached to a substrate, portions of the piezoelectric plate forming diaphragms spanning respective cavities in the substrate. A conductor pattern formed on a surface of the piezoelectric plate includes a plurality of interdigital transducers (IDTs) of a respective plurality of acoustic resonators including a shunt resonator and a series resonator, interleaved fingers of each of the plurality of IDTs disposed on one of the diaphragms. Radio frequency signals applied to the IDTs excite respective primary shear acoustic modes in the respective diaphragms. A thickness of a first dielectric layer disposed on the front surface between the fingers of the IDT of the shunt resonator is greater than a thickness of a second dielectric layer disposed on the front surface between the fingers of the IDT of the series resonator.