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.

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.

Acoustic resonator devices and methods are disclosed. An acoustic resonator device includes a substrate having a surface and a single-crystal piezoelectric plate having front and back surfaces. A back-side dielectric layer is formed on the back surface. An etch-stop layer is sandwiched between the surface of the substrate and the back-side dielectric layer. A portion of the piezoelectric plate, the back-side dielectric layer, and the etch-stop layer forms a diaphragm spanning a cavity in the substrate. An interdigital transducer (IDT) is formed on the front surface of the single-crystal piezoelectric plate with interleaved fingers of the IDT disposed on the diaphragm. The etch-stop layer is impervious to an etch process used to form the cavity.

1. A method of fabricating an RF filter comprising an array of resonators comprising the steps of: Obtaining a removable carrier with release layer; Growing a piezoelectric film on a removable carrier; Applying a first electrode to the piezoelectric film; Obtaining a backing membrane on a cover, with or without prefabricated cavities between the backing film and cover; Attaching the backing membrane to the first electrode; Detaching the removable carrier; Measuring and trimming the piezoelectric film as necessary; Selectively etching away the piezoelectric layer to fabricate discrete resonator islands; Etching down through coatings and backing membrane to a silicon dioxide layer between the backing membrane and the cover to form trenches; Applying a passivation layer into the trenches and around the piezoelectric islands; Depositing a second electrode layer over the piezoelectric film islands and surrounding passivation layer; Applying connections for subsequent electrical coupling to an interposer; Selectively removing second electrode material leaving coupled resonator arrays; Creating a gasket around perimeter of the resonator array; Thinning down cover to desired thickness; Optionally fabricating upper cavities between the backing membrane and cover by drilling holes through the cover and then selectively etching away the silicon dioxide; Dicing the wafer into flip chip single unit filter arrays; Obtaining an interposer; Optionally applying a dam to the interposer surface to halt overfill flow; Coupling the flip chip single unit filter array to pads of the interposer by reflow of the solder cap; Encapsulating with polymer underfill/overfill; and Singulating into separate filter modules, wherein wherein the piezoelectric layer comprises a mixed AlN single crystal layer a c-axis orientation.

An acoustic wave resonator includes a resonating part disposed on and spaced apart from a substrate by a cavity, the resonating part including a membrane layer, a first electrode, a piezoelectric layer, and a second electrode that are sequentially stacked. 0 Mg170 may be satisfied, Mg being a difference between a maximum thickness and a minimum thickness of the membrane layer disposed in the cavity.

A filter package comprising an array of piezoelectric films sandwiched between an array of upper electrodes and lower electrodes: the individual piezoelectric films and the upper electrodes being separated by a passivation material; the lower electrode being coupled to an interposer with a first cavity between the lower electrodes and the interposer; the filter package further comprising a silicon wafer of known thickness attached over the upper electrodes with an array of upper cavities between the silicon wafer and a silicon cover; each upper cavity aligned with a piezoelectric film in the array of piezoelectric films, the upper cavities having side walls comprising the passivation material.

A filter package comprising an array of piezoelectric films sandwiched between lower electrodes and an array of upper electrodes covered by an array of silicon membranes with cavities thereover: the lower electrode being coupled to an interposer with a first cavity between the lower electrodes and the interposer; the array of silicon membranes having a known thickness and attached over the upper electrodes with an array of upper cavities, each upper cavity between a silicon membrane of the array and a common silicon cover; each upper cavity aligned with a piezoelectric film, an upper electrode and silicon membrane, the upper cavities having side walls comprising SiO.sub.2; the individual piezoelectric films, their upper electrodes and silicon membranes thereover being separated from adjacent piezoelectric films, upper electrodes and silicon membranes by a passivation material.

A filter package comprising an array of piezoelectric films comprising an array of mixed single crystals that each comprise doped Aluminum Nitride, typically Al.sub.xGa.sub.(1-x)N or Sc.sub.xAl.sub.(1-x)N, that is sandwiched between an array of lower electrodes and an array of upper electrodes comprising metal layers and silicon membranes with cavities thereover: the array of lower electrodes being coupled to an interposer with a first cavity between the array of lower electrodes and the interposer; the array of silicon membranes having a known thickness and attached over the array of upper electrodes with an array of upper cavities, each upper cavity between a silicon membrane of the array and a common silicon cover; each upper cavity aligned with a piezoelectric film, an upper electrode and silicon membrane, the upper cavities having side walls comprising SiO.sub.2; the individual piezoelectric films, their upper electrodes and silicon membranes thereover being separated from adjacent piezoelectric films, upper electrodes and silicon membranes by a passivation material.

An acoustic resonator includes a resonant portion including a piezoelectric layer disposed between a first electrode and a second electrode, and a frame portion disposed along an outer edge of the second electrode. The frame portion includes three reflective portions reflecting lateral waves generated in the resonant portion.

Acoustic resonator devices and filters are disclosed. An acoustic resonator chip includes a piezoelectric plate attached to a substrate, a portion of the piezoelectric plate forming a diaphragm spanning a cavity in the substrate. A first conductor pattern formed on a surface of the piezoelectric plate includes an interdigital transducer with interleaved fingers on the diaphragm, and a first plurality of contact pads. A second conductor pattern is formed on a surface of an interposer, the second conductor pattern including a second plurality of contact pads. Each pad of the first plurality of contact pads is directly bonded to a respective pad of the second plurality of contact pads. A seal is formed between a perimeter of the acoustic resonator chip and a perimeter of the interposer.