Aspects of acoustic resonators and methods of manufacture of acoustic resonators are described, including acoustic resonators with thinner layers of piezoelectric material. In one example, a method of manufacturing an acoustic resonator includes providing a substrate, depositing a layer of piezoelectric material over the substrate by atomic layer deposition (ALD), and forming an electrode in contact with the layer of piezoelectric material. ALD is used to deposit highly uniform and conformal thin films of piezoelectric material and, in some cases, electrodes and encapsulation layers. The acoustic resonators described herein are better suited for the demands of new radio frequency (RF) filters, duplexers, transformers, and other components in front-end radio electronics and other applications.

A filter includes a piezoelectric film, an acoustic wave resonator including a functional electrode on the piezoelectric film, a capacitor connected in parallel to the acoustic wave resonator, and a resonator electrically connected to the acoustic wave resonator. The functional electrode includes first and second busbars facing each other and first and second electrodes respectively connected to the first and second busbars. The filter further includes a connection electrode on the piezoelectric film and electrically connecting the capacitor and the second busbar to each other. The capacitor includes the first busbar, an insulation film on the first busbar, and a capacitance electrode on the insulation film and that is electrically insulated from the first busbar.

A bulk acoustic wave (BAW) structure includes a single crystal piezoelectric material layer, a first electrode, a second electrode and an acoustic reflector. The first and second electrodes are respectively located on a first surface and a second surface of the single crystal piezoelectric material layer. The area of the second electrode is greater than or equal to that of the second surface of the single crystal piezoelectric material layer, and the contact area of the single crystal piezoelectric material layer with the second electrode is equal to the area of the second surface of the single crystal piezoelectric material layer. The acoustic reflector is disposed on a surface of the first electrode.

A laterally vibrating bulk acoustic wave (LVBAW) resonator includes a piezoelectric plate sandwiched between first and second metal layers. The second metal layer is patterned into an interdigital transducer (IDT) with comb-shaped electrodes having interlocking fingers. The width and pitch of the fingers of the electrodes determine the resonant frequency. A combined thickness of the first and second metal layers and the piezoelectric layer is less than the pitch of the interlocking fingers.

The invention provides a filter device, an RF front-end device and a wireless communication device. The filter device comprises a substrate, at least one resonance device, a passive device and a connector, wherein the at least one resonance device has a first side and a second side opposite to the first side, the substrate is located on the first side, and the passive device is located on the second side. The at least one resonance device is connected to the passive device through the connector. The RF filter device formed by integrating the resonance device (such as an SAW resonance device or a BAW resonance device) and the passive device (such as an IPD) in one die can broaden the passband width, has a high out-of-band rejection, and occupies less space in an RF front-end chip.

An acoustic wave device includes a piezoelectric layer made of one of lithium niobate or lithium tantalate and including first and second main surfaces, and first and second electrode fingers on the first main surface of the piezoelectric layer. The first and second electrode fingers are adjacent electrodes. When a center thickness of the piezoelectric layer in a region between the first and second electrode fingers is denoted by t.sub.p1, and a center-to-center distance between the first and second electrode fingers is denoted by p, t.sub.p1/p is about 0.5 or less. When a thickness of the piezoelectric layer in a region where the first electrode finger is located is denoted by t.sub.p2, t.sub.p1 > t.sub.p2.

An acoustic wave device includes a support substrate, a piezoelectric laminate, and first and second interdigital transducer electrodes. The piezoelectric laminate includes an intermediate layer provided directly or indirectly on the support substrate and a piezoelectric thin film provided on the intermediate layer. The first and second interdigital transducer electrodes are provided on the piezoelectric thin film of the piezoelectric laminate so as to be disposed in an identical or substantially identical plane. In the piezoelectric laminate, a thickness of a portion where the first interdigital transducer electrode is provided is different from a thickness of a portion where the second interdigital transducer electrode is provided.

Acoustic wave device is disclosed. the acoustic wave device can include a piezoelectric layer and an interdigital transducer electrode over the piezoelectric layer. The interdigital transducer electrode having a non-zero tilt angle. The non-zero tilt angle can between 5° to 15°. The interdigital transducer electrode is configured to shift stopband of the acoustic wave device and to reduce a slanted stopband.

An acoustic resonator device including a piezoelectric layer, a first electrode disposed adjacent to a first surface of the piezoelectric layer, and a second electrode disposed adjacent to a second surface of the piezoelectric layer. At least one of the first electrode and the second electrode includes a first conductive layer disposed adjacent to the piezoelectric layer and having a first acoustic impedance, and a second conductive layer disposed on a side of the first conductive layer opposite the piezoelectric layer and having a second acoustic impedance greater than the first acoustic impedance. The acoustic resonator device further includes at least one lateral feature for increasing quality factor Q of the acoustic resonator structure. The at least one lateral feature includes at least one of an air-ring between the piezoelectric layer and the second electrode, and a frame on at least one of the first electrode and the piezoelectric layer.

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.