An RF filter system includes a plurality of bulk acoustic wave resonators arranged in a circuit having serial and parallel shunt configurations of resonators. Each resonator having a reflector, a support member including a surface, a first electrode including tungsten, overlying the reflector, a piezoelectric film including crystalline aluminum scandium nitride overlapping the first electrode, a second electrode including tungsten overlapping the piezoelectric film and the first electrode, and a passivation layer including silicon nitride overlying the second electrode. Portions of the support member surface of at least one resonator define a cavity region having a portion of the first electrode of the at least one resonator is located within the cavity region. The pass band circuit response has a bandwidth corresponding to a thickness of at least one of the first electrode, piezoelectric film, second electrode, and passivation layer. The system can include single crystal or polycrystalline BAW resonators.

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 bulk-acoustic wave resonator includes: a substrate; a seed layer disposed on the substrate, and having a hexagonal crystal structure; a bottom electrode disposed on the seed layer; a piezoelectric layer at least partially disposed on the bottom electrode; and a top electrode disposed on the piezoelectric layer, wherein either one or both of the bottom electrode and the top electrode includes a scandium (Sc)-containing aluminum alloy 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.

An acoustic wave device includes a piezoelectric material substrate, an intermediate layer on the piezoelectric material substrate and composed of one or more materials selected from the group consisting of silicon oxide, aluminum nitride and sialon. A bonding layer is on the intermediate layer and is composed of one or more materials selected from the group consisting of tantalum pentoxide, niobium pentoxide, titanium oxide, mullite, alumina, and a high resistance silicon and hafnium oxide. A supporting body is composed of a polycrystalline ceramic and is bonded to the bonding layer by direct bonding, and an electrode is on the piezoelectric material substrate.

Embodiments of this disclosure relate to bulk acoustic wave resonators on a substrate. The bulk acoustic wave resonators include a first bulk acoustic wave resonator, a second bulk acoustic wave resonator, a conductor electrically connecting the first bulk acoustic wave resonator to the second bulk acoustic wave resonator, and an air gap positioned between the conductor and a surface of the substrate.

An RF filter comprising a resonator element and a polymer composition is provided. The polymer composition contains an aromatic polymer and has a melting temperature of about 240° C. or more. The polymer composition exhibits a dielectric constant of about 5 or less and dissipation factor of about 0.05 or less at a frequency of 10 GHz.

A MEMS resonator is operated at its parallel resonance frequency. An acoustic wave is propagated laterally away from a central region of the MEMS resonator through a piezoelectric layer of the MEMS resonator. The propagating acoustic wave is attenuated with concentric confiners that surround and are spaced apart from a perimeter of an electrode that forms the MEMS resonator.

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.

A back side of a diamond or other substrate is thinned using plasma etches and a mask situated away from the back side by a spacer having a thickness between 50 μm and 250 μm. Typically, a combined RIE/ICP etch is used to thin the substrate from 20-40 μm to less than 1 μm. For applications in which color centers are implanted or otherwise situated on a front side of the diamond substrate, after thinning, a soft graded etch is applied to reduce color center linewidth, particularly for nitrogen vacancy (NV) color centers.