Disclosed herein are embodiments of a method of manufacturing film bulk acoustic wave resonators. The method comprises forming a sacrificial layer over a surface of a substrate to form a plurality of film bulk acoustic wave resonators on the surface of the substrate, forming a piezoelectric film on the surface of the substrate to cover the sacrificial layer, and removing the sacrificial layer to form an air gap between the surface of the substrate and the piezoelectric film that has covered the sacrificial layer, the air gap corresponding to each of the plurality of film bulk acoustic wave resonators. The step of forming the piezoelectric film includes controlling a concentration distribution of an additive added to the piezoelectric film across the surface of the substrate to suppress a variation of the acoustic velocity of the piezoelectric film depending on a position on the main surface of the substrate.

A method for manufacturing a film bulk acoustic resonance device is disclosed. The proposed method, wherein the device has a specific resonant frequency, includes: providing a substrate having a recess, wherein the recess has a height; configuring a first piezoelectric material layer on the substrate, and causing the recess to form an air gap; configuring a lower electrode on the first piezoelectric material layer; when the height is in a first range, causing a resonant frequency of the film bulk acoustic resonance device versus the height to have a first slope; when the height is in a second range, causing the resonant frequency versus the height to have a second slope; and causing the first slope to be smaller than the second slope.

A method for manufacturing a film bulk acoustic resonance device is disclosed. The proposed method, wherein the device has a specific resonant frequency, includes: providing an upper electrode; providing a lower electrode; configuring a first piezoelectric material layer between the upper electrode and the lower electrode; configuring a resonant frequency determining metal layer on the upper electrode, wherein the resonant frequency determining metal layer has a thickness; causing a resonant frequency of the film bulk acoustic resonance device and the thickness to form a curve; and when the thickness on the curve changes linearly, causing the resonant frequency to change non-linearly.

A film bulk acoustic resonator (FBAR) structure includes a bottom cap wafer, a piezoelectric layer disposed on the bottom cap wafer, the piezoelectric layer including a single crystalline piezoelectric material, a bottom electrode disposed below the piezoelectric layer; a top electrode disposed above the piezoelectric layer; and a cavity disposed below the bottom electrode.

An apparatus includes a piezoelectric thin film suspended above a carrier substrate, where the piezoelectric thin film is of one of lithium niobate (LiNbO.sub.3) or lithium tantalate (LiTaO.sub.3) adapted to propagate an acoustic wave in a Lamb wave mode excited by a component of an electric field that is oriented in a longitudinal direction along a length of the piezoelectric thin film. A signal electrode is disposed on, and in physical contact with, the piezoelectric thin film and oriented perpendicular to the longitudinal direction. A ground electrode disposed on, and in physical contact with, the piezoelectric thin film and oriented perpendicular to the longitudinal direction, where the ground electrode is separated from the signal electrode by a gap comprising a longitudinal distance and in which the acoustic wave resonates. A release window is formed within the piezoelectric thin film adjacent to the ground electrode.

A method and structure for a 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. A 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.

Techniques for improving acoustic wave device structures are disclosed, including filters and systems that may include such devices. An apparatus may comprise a first electrical filter including an acoustic wave device. The first electrical may having a first filter band in a Super High Frequency (SHF) band or an Extremely High Frequency (EHF) band to facilitate compliance with a regulatory requirement or a standards setting organization specification. For example, the first electrical filter may comprise a notch filter having a notch band overlapping at least a portion of an Earth Exploration Satellite Service (EESS) band to facilitate compliance with a regulatory requirement or the standards setting organization specification for the Earth Exploration Satellite Service (EESS) band.

Devices and processes for preparing devices are described for a bulk acoustic wave resonator. A stack includes a first electrode that is coupled to a first side of a piezoelectric layer and a second electrode that is coupled to a second side of the piezoelectric layer. The stack is configured to resonate in response to an electrical signal applied between the first electrode and the second electrode. A cavity frame is coupled to the first electrode and to the substrate. The cavity frame forms a perimeter around a cavity. Optionally, a heat dissipating frame is formed and coupled to the second electrode. The cavity frame and/or the heat dissipating frame improve the thermal stability of the bulk acoustic resonator.

A bulk acoustic wave resonator, a filter, and a radio frequency communication system are provided. The bulk acoustic wave resonator includes a substrate and a bottom electrode layer, where a cavity is formed therebetween. The bulk acoustic wave resonator also includes a piezoelectric layer formed on the bottom electrode layer and over the cavity, and a top electrode layer formed over the piezoelectric layer. At least one of the bottom electrode layer and the top electrode layer has a convex portion or concave portion. The convex portion is located in a region of the cavity and is protruded facing away from a bottom of the cavity, and the concave portion is located in the region of the cavity and is recessed towards the bottom of the cavity. Each of the convex portion and the concave portion is located in a peripheral region surrounding the piezoelectric layer.

The disclosure provides a resonator and a filter. The resonator includes: a substrate; and a multilayer structure formed on the substrate. The multilayer structure successively includes a lower electrode layer, a piezoelectric layer and an upper electrode layer from bottom to top. A cavity is formed between the substrate and the multilayer structure, and the cavity includes a lower half cavity below an upper surface of the substrate and an upper half cavity beyond the upper surface of the substrate and protruding toward the multilayer structure. A resonator with novel structure and good performance is formed by providing the cavity with the lower half cavity below the upper surface of the substrate and the upper half cavity above the upper surface of the substrate.