A formation method of a filter device includes: forming a first layer by providing a first substrate and forming a resonance device preprocessing layer with a first side and a second side opposite to the first side, wherein the first substrate is located on the first side; forming a second layer by providing a second substrate and forming a first passive device with a third side and a fourth side opposite to the third side, wherein the second substrate is located on the third side; connecting the first layer located on the fourth side and the second layer located on the second side; removing the first substrate; and forming at least one first resonance device based on the resonance device preprocessing layer. The resonance device and the passive device are integrated in one die to form a filter device, which requires less space in an RF front-end chip.

An acoustic wave filter includes series resonators and parallel resonators that have a piezoelectric film on an identical substrate and have a lower electrode and an upper electrode, wherein: one of the series resonators and the parallel resonators have a temperature compensation film on a face of the lower electrode or the upper electrode that is opposite to the piezoelectric film in a resonance region, the compensation film having an elastic constant of a temperature coefficient of which sign is opposite to a sign of a temperature coefficient of an elastic constant of the piezoelectric film; and the other have an added film on the same side as the temperature compensation film on the lower electrode side or the upper electrode side compared to the piezoelectric film in the resonance region in the one of the series resonators and the parallel resonators.

In an elastic wave device, a piezoelectric substrate is laminated on a support substrate including a recess. On one of a first principal surface and a second principal surface of the piezoelectric substrate, a functional electrode including an IDT electrode is provided. Passing-through sections are provided in the piezoelectric substrate and connected to a hollow section enclosed by the recess and the piezoelectric substrate. In a plan view of the piezoelectric substrate seen from the first principal surface, at least a portion of the passing-through sections is inside a minimum rectangular or substantially rectangular region encompassing an outer circumference of a region including the functional electrode.

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.

A film bulk acoustic wave resonator includes a first substrate; a first insulating material layer, formed on the first substrate; a first cavity, formed in the first insulating material layer with an opening facing away from the first substrate; and an acoustic-wave resonant plate, including a first electrode, a piezoelectric oscillation plate, and a second electrode stacked on the first insulating material layer. The piezoelectric oscillation plate is disposed between the first electrode and the first electrode. The first electrode includes a first electrode cavity above the first cavity. The second electrode includes a second cavity above the first cavity. At least a portion of a boundary of the piezoelectric oscillation plate is formed by a boundary of the first electrode cavity and a boundary of the second electrode cavity. The boundary of the piezoelectric oscillation plate has an irregular polygonal shape without having two parallel edges.

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.

Methods of manufacturing an electronic device formed in a cavity may include providing a first substrate having a first side wall including a first metal formed along a periphery on a bottom surface thereof and surrounding an electronic circuit disposed on the bottom surface, providing a second substrate having a second side wall including a second metal and a third metal formed along a periphery on a top surface thereof, aligning the first substrate with the second substrate with the first side wall opposing and contacting the second side wall to internally define a cavity between the bottom surface of the first substrate, the top surface of the second substrate, the first side wall ,and the second side wall, and heating and bonding the first substrate and the second substrate by transient liquid phase bonding.

Proposed is a layer structure (1100, 1030) comprising a crystalline piezoelectric III-N layer (1110, 1032) epitaxially grown over a metal layer which is epitaxially grown over a rare earth oxide layer on a semiconductor (1102, 1002). The rare earth oxide layer includes at least two discrete portions (1104, 1004), and the metal layer includes at least one metal portion (1108, 1006) that partially overlaps adjacent discrete portions, preferably forming a bridge over an air gap (1008), particularly suitable for RF filters.

A method and structure for an essentially single crystal acoustic electronic device. The device includes a substrate having an enhancement layer formed overlying its surface region and an air cavity formed through a portion of the substrate. An essentially 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.

A method is provided for forming a piezoelectric layer during a corresponding deposition sequence. The method includes sputtering aluminum nitride onto a sputtering substrate inside a reaction chamber having a gas atmosphere, the gas atmosphere initially including nitrogen gas and an inert gas, causing growth of the piezoelectric layer with a polarity in a negative direction. The method further includes adding a predetermined amount of oxygen containing gas to the gas atmosphere over a predetermined period of time, while continuing the sputtering of the aluminum nitride onto the sputtering substrate during a remainder of the deposition sequence, such that the piezoelectric layer is monolithic. The predetermined amount of oxygen containing gas causes the polarity of the aluminum nitride piezoelectric layer to invert from the negative direction to a positive direction, opposite the negative direction.