Acoustic filters are disclosed. A filter device includes a plurality of resonators connected in a ladder filter circuit, each resonator of the plurality of resonators comprising an interdigital transducer (IDT) with interleaved fingers disposed on a respective piezoelectric diaphragm. A first frequency setting dielectric layer having a first thickness is disposed over the interleaved fingers of one or more IDTs of a first subset of the plurality of resonators. A second frequency setting dielectric layer having a second thickness greater than the first thickness is disposed over the interleaved fingers of one or more IDTs of a second subset of the plurality of resonators, wherein the first subset and the second subset are not identical.

An RF circuit device using modified lattice, lattice, and ladder circuit topologies. The devices can include four resonator devices and four shunt resonator devices. In the ladder topology, the resonator devices are connected in series from an input port to an output port while shunt resonator devices are coupled the nodes between the resonator devices. In the lattice topology, a top and a bottom serial configurations each includes a pair of resonator devices that are coupled to differential input and output ports. A pair of shunt resonators is cross-coupled between each pair of a top serial configuration resonator and a bottom serial configuration resonator. The modified lattice topology adds baluns or inductor devices between top and bottom nodes of the top and bottom serial configurations of the lattice configuration. These topologies may be applied using single crystal or polycrystalline bulk acoustic wave (BAW) resonators.

An acoustic resonator device, filter devices, and methods of making the same. An acoustic resonator device includes a substrate having a surface and a single-crystal piezoelectric plate having front and back surfaces, where 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 device further includes an interdigital transducer formed on the front surface of the piezoelectric plate, where interleaved fingers of the IDT disposed on the diaphragm are configured such that a radio frequency signal applied to the IDT excites a primary shear acoustic mode in the diaphragm. The interleaved fingers include a first layer adjacent the diaphragm and a second layer over the first layer, the second layer having a narrower width than the first layer.

There is disclosed acoustic resonators and filter devices. An acoustic resonator 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 (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 comprise a first layer adjacent the diaphragm and a second layer over the first layer opposite the diaphragm, the second layer having a greater width than the first layer.

Disclosed is a method of manufacturing a piezoelectric thin film resonator on a non-silicon substrate, including the following steps: depositing a copper thin film on a silicon wafer; coating photoresist on the copper thin film to perform photoetching so as to remove photoresist in an air gap region under the piezoelectric thin film resonator to be disposed; electroplating-depositing a copper layer, and removing photoresist to obtain a stepped peel sacrifice layer; coating polyimide and performing imidization by heat treatment, making a sandwich structure of the piezoelectric thin film resonator above the polyimide layer; performing etching for the polyimide layer in a region not covered by the piezoelectric thin film resonator by oxygen plasma; placing the obtained device into a copper corrosion solution to dissolve the copper around and under the piezoelectric thin film resonator, attaching a drum coated with polyvinyl alcohol glue onto the piezoelectric thin film resonator, releasing and peeling it from the silicon wafer and then transferring it to a desired non-silicon substrate; washing the drum with hot water to separate the drum from the piezoelectric thin film resonator so as to complete the manufacturing process.

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.

A method of manufacture for an acoustic resonator or filter device. In an example, the present method can include forming metal electrodes with different geometric areas and profile shapes coupled to a piezoelectric layer overlying a substrate. These metal electrodes can also be formed within cavities of the piezoelectric layer or the substrate with varying geometric areas. Combined with specific dimensional ratios and ion implantations, such techniques can increase device performance metrics. In an example, the present method can include forming various types of perimeter structures surrounding the metal electrodes, which can be on top or bottom of the piezoelectric layer. These perimeter structures can use various combinations of modifications to shape, material, and continuity. These perimeter structures can also be combined with sandbar structures, piezoelectric layer cavities, the geometric variations previously discussed to improve device performance metrics.

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 and a thickness ts, the back surface attached to the surface of the substrate except for portions of the piezoelectric plate forming a plurality of diaphragms that span respective cavities in the substrate. A conductor pattern is formed on the front surface of the piezoelectric plate, the conductor pattern comprising a plurality of interdigital transducers (IDTs) of a plurality of acoustic resonators, interleaved fingers of each IDT of the plurality of IDTs disposed on a respective diaphragm of the plurality of diaphragms. Zero or more dielectric layers are deposited over all of the IDTs and the diaphragms, wherein a total thickness of the zero or more dielectric layers is the same for all of the plurality of acoustic resonators.

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. After removing material from the dielectric passivation/tuning layer, cavities are formed in the substrate such that interleaved fingers of each IDT are disposed on a respective diaphragm spanning a respective cavity

Acoustic filters and methods are disclosed. A single-crystal piezoelectric is attached to a substrate, portions of the piezoelectric plate forming one or more diaphragms spanning respective cavities in the substrate. A conductor pattern is formed on the piezoelectric plate, the conductor pattern including a plurality of interdigital transducers (IDTs) of a plurality of resonators, interleaved fingers of each of the plurality of IDTs disposed on a respective diaphragm of the one or more diaphragms. A first frequency setting dielectric layer having a first thickness is disposed over the fingers of the IDTs of a first subset of the plurality of resonators. A second frequency setting dielectric layer having a second thickness greater than the first thickness is disposed over the fingers of the IDTs of a second subset of the plurality of resonators, wherein the first subset and the second subset are not identical.