Methods related to gradient raised frames in film bulk acoustic resonators. According to certain aspects, a method for fabricating a film bulk acoustic resonator device can include: forming a first metal layer over a substrate; forming a piezoelectric layer; forming a second metal layer, the piezoelectric layer positioned between the first and second metal layers; and forming a gradient raised frame implemented relative to one of the first and second metal layers and configured to improve reflection of lateral mode waves and to reduce conversion of main mode waves into lateral mode waves.

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.

A bulk acoustic resonator device is provided that includes a bulk acoustic resonator chip having a substrate; a piezoelectric layer attached to the substrate either directly or via one or more intermediate layers; and a first conductor pattern on the piezoelectric layer, the first conductor pattern comprising an interdigitated transducer (IDT). Moreover, an interposer is provided having a surface facing the piezoelectric layer and having a second conductor pattern on the surface of the interposer. A conductive metal bump is between the piezoelectric layer and the interposer that electrically connects the first conductor pattern to the second conductor pattern; and a cover is bonded both to the substrate and to a portion of the surface of the interposer. The cover seals an interior of the bulk acoustic resonator chip.

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.

Disclosed are polarization-inverted higher-order plate-mode resonators and methods for making the same. In an aspect, a plate-mode resonator includes a first piezoelectric layer having a first crystal orientation specified by a first set of Euler angles .sub.1, .sub.1, and .sub.1, a dielectric layer disposed on a top surface of the first piezoelectric layer, a second piezoelectric layer, disposed on a top surface of the dielectric layer, having a second crystal orientation specified by a second set of Euler angles .sub.2, .sub.2, and .sub.2, wherein az is approximately equal to .sub.1, wherein a difference between .sub.2 and .sub.1 is approximately 180 degrees, and wherein .sub.2 is approximately equal to .sub.1, and a metallization structure disposed on a top surface of the second piezoelectric layer, the metallization structure comprising at least one interdigital transducer.

An acoustic filter is provide that includes a substrate; a piezoelectric plate attached to the substrate; and a plurality of bulk acoustic resonators including one or more shunt resonators and one or more series resonators. One or more of the shunt resonators includes an interdigital transducer having interdigital fingers on the piezoelectric plate; a front-side frequency setting layer at least partially on a front side of the at least one shunt resonator; and a back-side frequency setting layer on a back side of the at least one shunt resonator. Moreover, a thickness of the back-side frequency setting layer is at least 30% of a total thickness of the front-side frequency setting layer and the back-side frequency setting layer.

The present disclosure provides a bulk acoustic wave resonator, a method for manufacturing a bulk acoustic wave resonator and an electronic device, and belongs to the field of communication technology. The bulk acoustic wave resonator of the present disclosure includes: a first base substrate, a first electrode, a piezoelectric layer, and a second electrode; the first electrode is on the first base substrate, the second electrode is on a side of the first electrode away from the first base substrate, the piezoelectric layer is between the first electrode and the second electrode; and orthographic projections of any two of the first electrode, the piezoelectric layer and the second electrode on the first base substrate at least partially overlap with each other; wherein an acoustic velocity of a material of the piezoelectric layer is no less than 18000 m/s.

A cavity structure of a bulk acoustic resonator and a manufacturing process. The cavity structure comprises a substrate and a cavity formed on the substrate, a support layer is arranged on the substrate to form the cavity in a surrounding manner, a release channel in communication with the cavity is formed above the substrate in a same layer with the cavity, and the release channel extends, in parallel to the substrate, in a peripheral area of the cavity. There is no need to manufacture a release hole, which simplifies the manufacturing process of the resonator, thereby avoiding weakening the performance of the resonator due to damage to the structure of the piezoelectric layer around the electrode layer when manufacturing the release hole.

Acoustic resonator devices and filters are disclosed. An acoustic resonator includes a substrate and a piezoelectric plate having front and back surfaces, the back surface attached to the substrate. A decoupling dielectric layer is on the front surface of the piezoelectric plate. An interdigital transducer (IDT) is formed over the decoupling dielectric layer such that interleaved fingers of the IDT are over a portion of the piezoelectric plate suspended across a cavity formed in the substrate. A thickness of the interleaved fingers is greater than or equal to 1.17 times a thickness of the piezoelectric plate and less than or equal to 1.7 times the thickness of the piezoelectric plate.

A filter device with multiple piezoelectric plate thicknesses if fabricated on a single chip by bonding a piezoelectric plate to a surface of a substrate having swimming pool shunt and series cavities. Non-selected areas of the plate have a thickness for shunt resonators and form shunt membranes of the plate that span the swimming pool shunt cavities. Selected areas of a back surface of the plate have a thickness for series resonators and form series membranes of the plate that span the swimming pool series cavities but not the swimming pool shunt cavities. The thickness for series resonators is thinner than that for shunt resonators. Shunt interdigital transducers (IDTs) are on a front surface of the plate over the swimming pool shunt cavities; and series IDTs are on a front surface of the plate over the swimming pool series cavities.