Abstract: Acoustic resonators and filter devices. An acoustic resonator includes a piezoelectric plate having front and back surfaces, a portion of the piezoelectric plate forming a diaphragm, and a conductor pattern on the front surface, the conductor pattern including a multi-mark interdigital transducer (IDT), fingers of the IDT on the diaphragm. A thickness between the front and back surfaces is greater than or equal to 200 nm and less than or equal to 1000 nm.

Abstract: Acoustic resonators and filter devices. An acoustic resonator including a piezoelectric plate having front and back surfaces, a portion of the piezoelectric plate forming a diaphragm, and a conductor pattern on the front surface, the conductor pattern including an interdigital transducer (IDT), fingers of the IDT on the diaphragm. A thickness between the front and back surfaces is greater than or equal to 200 nm and less than or equal to 1000 nm. The IDT comprises a first portion having a first pitch and a first mark and a second portion having a second pitch and a second mark not equal to the first pitch and first mark.

Abstract: Acoustic resonators and filter devices. An acoustic resonator includes a piezoelectric plate having front and back surfaces, a portion of the piezoelectric plate forming a diaphragm, and a conductor pattern on the front surface, the conductor pattern including an interdigital transducer (IDT), fingers of the IDT on the diaphragm. A thickness of the interleaved fingers is greater than or equal to 0.85 times a thickness of the piezoelectric plate and less than or equal to 2.5 times the thickness of the piezoelectric plate. The IDT comprises a first portion having a first pitch and a first mark and a second portion having a second pitch and a second mark not equal to the first pitch and first mark.

Abstract: Filters and methods of making filters are disclosed. A filter device includes a substrate, a piezoelectric plate, and an acoustic Bragg reflector between a surface of the substrate and a back surface of the piezoelectric plate. A first portion of the piezoelectric plate has a first thickness, and a second portion of the piezoelectric plate has a second thickness less than the first thickness. A conductor pattern on front surfaces of the first and second portions of the piezoelectric plate includes a first interdigital transducer (IDT) with interleaved fingers on the first portion, and a second IDT with interleaved fingers on the second portion.

Abstract: Acoustic resonators and filter devices. An acoustic resonator includes a piezoelectric plate having front and back surfaces, a portion of the piezoelectric plate forming a diaphragm, and a conductor pattern on the front surface, the conductor pattern including a multi-mark interdigital transducer (IDT), with fingers of the IDT on the diaphragm. A thickness of the interleaved fingers is greater than or equal to 0.85 times a thickness of the piezoelectric plate and less than or equal to 2.5 times the thickness of the piezoelectric plate.

Abstract: Acoustic resonators and filter devices. An acoustic resonator includes a piezoelectric plate having front and back surfaces, a portion of the piezoelectric plate forming a diaphragm, and a conductor pattern on the front surface, the conductor pattern including an interdigital transducer (IDT), interleaved fingers of the IDT on the diaphragm. A ratio of a mark of the interleaved fingers to a pitch of the interleaved fingers is greater than or equal to 0.12 and less than or equal to 0.3. The pitch of the interleaved fingers is greater than or equal to 6 times a thickness of the piezoelectric plate and less than or equal to 12.5 times the thickness of the piezoelectric plate.

Abstract: Acoustic resonators and filter devices. An acoustic resonator includes a piezoelectric plate having front and back surfaces, the back surface attached to a surface of a substrate, a portion of the piezoelectric plate forming a diaphragm spanning a cavity in the substrate, and a conductor pattern on the front surface, the conductor pattern including an interdigital transducer (IDT), interleaved fingers of the IDT on the diaphragm. A ratio of a mark of the interleaved fingers to a pitch of the interleaved fingers is greater than or equal to 0.12 and less than or equal to 0.3. A thickness between the front and back surfaces is greater than or equal to 200 nm and less than or equal to 1000 nm.

Abstract: Acoustic resonator devices and acoustic filter devices. An acoustic resonator includes a piezoelectric plate having front and back surfaces, a portion of the piezoelectric plate forming a diaphragm, and a conductor pattern on the front surface, the conductor pattern comprising an interdigital transducer (IDT), interleaved fingers of the IDT on the diaphragm. A ratio of a mark of the interleaved fingers to a pitch of the interleaved fingers is greater than or equal to 0.12 and less than or equal to 0.3. A thickness of the interleaved fingers is greater than or equal to 0.85 times a thickness of the piezoelectric plate and less than or equal to 2.5 times the thickness of the piezoelectric plate.

Abstract: Methods of fabricating filter devices are disclosed. A back surface of a piezoelectric plate having a first thickness is attached to a substrate. The front surface of the piezoelectric plate is selectively etched to thin a portion of the piezoelectric plate from the first thickness to a second thickness less than the first thickness. Cavities are formed in the substrate such that portions of the piezoelectric plate form a plurality of diaphragms spanning respective cavities. A conductor pattern is formed on the front surface. The conductor pattern includes a first interdigital transducer (IDT) with interleaved fingers on a first diaphragm having the first thickness and a second IDT with interleaved fingers on a second diaphragm having the second thickness.

Abstract: Resonator and filter devices and methods of fabrication. A resonator chip includes a substrate, a piezoelectric plate, and an acoustic Bragg reflector between the substrate and a back surface of the piezoelectric plate. A conductor pattern on a front surface of the piezoelectric plate includes a first plurality of contact pads and an interdigital transducer (IDT). The IDT and the piezoelectric plate are configured such that a radio frequency signal applied to the IDT excites a shear primary acoustic mode within the piezoelectric plate. The acoustic Bragg reflector is configured to reflect the shear primary acoustic mode. An interposer has a second plurality of contact pads on a back surface. A seal connects a perimeter of the piezoelectric plate to a perimeter of the interposer. Each contact pad of the first plurality of contact pads is directly connected to a respective contact pad of the second plurality of contact pads.

Abstract: Acoustic resonators, acoustic filter devices and methods of making the same. An acoustic resonator device includes a piezoelectric layer having front and back surfaces, a high acoustic velocity layer on the back surface, and an interdigital transducer (IDT) on the front surface. The high acoustic velocity layer has a higher acoustic velocity than an acoustic velocity of the piezoelectric layer.

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 the perimeter of the cavity is corner-less.

Abstract: Acoustic resonator devices and filters, and methods of making the same. An acoustic resonator includes a piezoelectric plate and an interdigital transducer (IDT) including interleaved fingers on the piezoelectric plate. The piezoelectric plate and the IDT are configured such that a radio frequency signal applied to the IDT excites a shear primary acoustic mode within the piezoelectric plate. The acoustic resonator further includes a front-side dielectric layer on the piezoelectric plate between the fingers of the IDT, wherein a resonance frequency of the acoustic resonator device has an inverse dependence on a thickness of the front-side dielectric layer.

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: An acoustic filter includes a piezoelectric plate on a substrate. Portions of the piezoelectric plate form one or more diaphragms, each diaphragm spanning a respective cavity in the substrate. A conductor pattern on a front surface of the piezoelectric plate includes interdigital transducers (IDTs) of acoustic resonators including a shunt resonator and a series resonator. Interleaved fingers of each IDT are on a diaphragm of the one or more diaphragms. A first dielectric layer with a first thickness is between the fingers of the IDT of the shunt resonator, and a second dielectric layer with a second thickness less than the first thickness is between the fingers of the IDT of the series resonator. The piezoelectric plate and the IDTs are configured such that radio frequency signals applied to the IDTs excite respective primary shear acoustic modes within the diaphragms.

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 over a frequency range including a resonance frequency and an anti-resonance frequency of the acoustic resonator device.

Abstract: Methods of fabricating acoustic filters are disclosed. The back of a piezoelectric plate is bonded to a surface of a substrate. The thickness of the piezoelectric plate is measured at a plurality of positions. Excess material is removed from the front surface of the piezoelectric plate in accordance with the thickness measurements to improve the thickness uniformity of the piezoelectric plate. After removing the excess material, a conductor pattern including a plurality of ladder filter circuits is formed on the front surface. Each ladder filter circuit includes at least one shunt resonator and at least one series resonator, each of which has an interdigital transducer (IDT). Cavities are formed in the substrate such that portions of the piezoelectric plate form a plurality of diaphragms spanning respective cavities. After the cavities are formed, interleaved fingers of each IDT are on a respective one of the plurality of diaphragms.

Abstract: Resonator devices are disclosed. An acoustic resonator device includes a piezoelectric plate having front and back surfaces, an acoustic Bragg reflector on the back surface, and an interdigital transducer (IDT) on the front surface. The acoustic Bragg reflector reflects a primary shear acoustic mode excited by the IDT in the piezoelectric plate over a frequency range including a resonance frequency and an anti-resonance frequency of the acoustic resonator device.

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 and a piezoelectric plate attached to the substrate, the piezoelectric plate forming diaphragms spanning respective cavities in the substrate. A first portion of the piezoelectric plate has a first thickness. A front surface of a second portion of the piezoelectric plate is recessed relative to a front surface of the first portion of the piezoelectric plate such that the second portion of the piezoelectric plate has a second thickness less than the first thickness. A conductor pattern is formed on the front surfaces of the first and second portions of the piezoelectric plate. The conductor pattern includes a first interdigital transducer (IDT) with interleaved fingers on a diaphragm having the first thickness, and a second IDT with interleaved fingers on a diaphragm having the second thickness.