A method and structure for single crystal acoustic electronic device. The device includes a substrate having an enhancement layer formed overlying its surface region, a support layer formed overlying the enhancement layer, and an air cavity formed through a portion of the support layer. Single crystal piezoelectric material is formed overlying the air cavity and a portion of the enhancement layer. Also, a first electrode material coupled to the backside surface region of the crystal piezoelectric material and spatially configured within the cavity. A second electrode material is formed overlying the topside of the piezoelectric material, and a dielectric layer formed overlying the second electrode material. Further, one or more shunt layers can be formed around the perimeter of a resonator region of the device to connect the piezoelectric material to the enhancement layer.

An acoustic resonator filter includes at least one series acoustic resonator electrically connected between a first port and a second port in series, through which a radio frequency (RF) signal passes; at least one second shunt acoustic resonator electrically shunt-connected between the at least one series acoustic resonator and a ground; and at least one first shunt acoustic resonator electrically shunt-connected between the at least one series acoustic resonator and a ground and having a resonance frequency higher than a resonance frequency of the at least one second shunt acoustic resonator. At least one shunt acoustic resonator, among the at least one first shunt acoustic resonator and the at least one second shunt acoustic resonator has a temperature coefficient of frequency (TCF) corresponding to resonance frequency sensitivity more insensitive than resonance frequency sensitivity according to a change in temperature of the at least one series acoustic resonator filter.

Hybrid filters and more particularly filters having acoustic wave resonators (AWRs) and lumped component (LC) resonators and packages therefor are described. In an example, a packaged filter includes a package substrate, the package substrate having a first side and a second side, the second side opposite the first side. A first acoustic wave resonator (AWR) device is coupled to the package substrate, the first AWR device comprising a resonator. A plurality of inductors is in the package substrate.

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.

Disclosed is a radio frequency multiplexer having an M number of multiplexer branches each having an outer port terminal coupled to a common outer node, wherein M is a positive counting number. Each of the M number of multiplexer branches comprises a multi-bandpass filter configured to filter an N number of bands multiplexed by the radio frequency multiplexer to pass an individual group of N/M bands, wherein N is a positive counting number greater than one and equal to a total number of bands to be multiplexed. Each of the M number of multiplexer branches further includes an N/M number of resonator branches each having a band port terminal configured to pass a single band and an inner branch terminal coupled to an inner port terminal of the multi-bandpass filter at a common inner node.

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.

A filter (10) includes two capacitors (C1a and C1b) that are connected in series on a path connecting an input terminal (101a) and an output terminal (102a), an inductor (L2) that is connected in parallel with a series circuit including the two capacitors (C1a and C1b), and a parallel-arm resonator (P1) that is connected between the ground and a node (N) between the two capacitors (C1a and C1b) on the path.

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.

A method and structure for single crystal acoustic electronic device. The device includes a substrate having an enhancement layer formed overlying its surface region, a support layer formed overlying the enhancement layer and an air cavity formed through a portion of the support layer. Single crystal piezoelectric material is formed overlying the air cavity and a portion of the enhancement layer. Also, a first electrode material coupled to the backside surface region of the crystal piezoelectric material and spatially configured within the cavity. A second electrode material is formed overlying the topside of the piezoelectric material, and a dielectric layer formed overlying the second electrode material. Further, one or more shunt layers can be formed around the perimeter of a resonator region of the device to connect the piezoelectric material to the enhancement layer.

An acoustic resonator filter package includes an acoustic resonator including a piezoelectric layer, a first electrode disposed on a first surface of the piezoelectric layer, and a second electrode disposed on a second surface of the piezoelectric layer; a first substrate having an upper surface on which the acoustic resonator is disposed, the first substrate comprising a first coupling member surrounding the acoustic resonator; a filter spaced apart from the acoustic resonator in an upward direction; a second substrate having a lower surface on which the filter is disposed, the second substrate including a second coupling member disposed above the first coupling member; and a connection member connecting the first coupling member and the second coupling member to each other, the connection member being made of a material different from a material of which the first coupling member and the second coupling member are made.