An integrated circuit film bulk acoustic resonator (FBAR) device having multiple resonator thicknesses is formed on a common substrate in a stacked configuration. In an embodiment, a seed layer is deposited on a substrate, and one or more multi-layer stacks are deposited on the seed layer, each multi-layer stack having a first metal layer deposited on a first sacrificial layer, and a second metal layer deposited on a second sacrificial layer. The second sacrificial layer can be removed and the resulting space is filled in with a piezoelectric material, and the first sacrificial layer can be removed to release the piezoelectric material from the substrate and suspend the piezoelectric material above the substrate. More than one multi-layer stack can be added, each having a unique resonant frequency. Thus, multiple resonator thicknesses can be achieved on a common substrate, and hence, multiple resonant frequencies on that same substrate.

Provided is an aluminum nitride film in which, aluminum nitride crystal grains containing a metal element differing from aluminum and substituting for aluminum are main crystal grains of a polycrystalline film formed of crystal grains, and a concentration of the metal element in a grain boundary between the aluminum nitride crystal grains in at least one region of first and second regions corresponding to both end portions of the polycrystalline film in a film thickness direction of the polycrystalline film is higher than a concentration of the metal element in a center region of the aluminum nitride crystal grain in the at least one region, and is higher than a concentration of the metal element in a grain boundary between the aluminum nitride crystal grains in a third region located between the first region and the second region in the film thickness direction of the polycrystalline film.

An RF filter system including a plurality of BAW resonators arranged in a circuit, the circuit including a serial configuration of resonators and a parallel shunt configuration of resonators, the circuit having a circuit response corresponding to the serial configuration and the parallel configuration of the plurality of bulk acoustic wave resonators including a transmission loss from a pass band having a bandwidth from 5.490 GHz to 5.835 GHz. Resonators include a support member with a multilayer reflector structure; a first electrode including tungsten; a piezoelectric film including aluminum scandium nitride; a second electrode including tungsten; and a passivation layer including silicon nitride. At least one resonator includes at least a portion of the first electrode located within a cavity region defined by a surface of the support member.

An RF filter system including a plurality of BAW resonators arranged in a circuit, the circuit including a serial configuration of resonators and a parallel shunt configuration of resonators, the circuit having a circuit response corresponding to the serial configuration and the parallel configuration of the plurality of bulk acoustic wave resonators including a transmission loss from a pass band having a bandwidth from 5.170 GHz to 5.835 GHz. Resonators include a support member with a multilayer reflector structure; a first electrode including tungsten; a piezoelectric film including aluminum scandium nitride; a second electrode including tungsten; and a passivation layer including silicon nitride. At least one resonator includes at least a portion of the first electrode located within a cavity region defined by a surface of the support member.

A piezoelectric transducer for measuring a force includes a base element; a pre-loading element; at least one effective main seismic mass aggregation of pre-loaded parts capable of producing the force when being accelerated; a main piezoelectric ceramic element including a first piezoelectric ceramic; at least one compensation seismic mass aggregation of pre-loaded parts capable of producing a compensation force when being accelerated; a compensation piezoelectric ceramic element including a second piezoelectric ceramic. The first piezoelectric ceramic has a thermal sensitivity shift smaller than the second piezoelectric ceramic. The main piezoelectric ceramic element is oriented with respect to the force to be measured and the compensation piezoelectric ceramic element is oriented with respect to the compensation force such that the main electric charge and the compensation electric charge are opposite in polarity.

An RF triplexer 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 RF triplexer 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 RF triplexer 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 to 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 surface acoustic wave device is disclosed. The surface acoustic wave device can include a ceramic substrate, a piezoelectric layer over the ceramic substrate, and an interdigital transducer electrode over the piezoelectric layer. The ceramic substrate can be a polycrystalline spinel substrate. The surface acoustic wave device can also include a temperature compensating layer over the interdigital transducer electrode.

A piezoelectric transducer for measuring a force includes a base element; a pre-loading element; at least one effective main seismic mass aggregation of pre-loaded parts capable of producing the force when being accelerated; a main piezoelectric ceramic element including a first piezoelectric ceramic; at least one compensation seismic mass aggregation of pre-loaded parts capable of producing a compensation force when being accelerated; a compensation piezoelectric ceramic element including a second piezoelectric ceramic. The first piezoelectric ceramic has a thermal sensitivity shift smaller than the second piezoelectric ceramic. The main piezoelectric ceramic element is oriented with respect to the force to be measured and the compensation piezoelectric ceramic element is oriented with respect to the compensation force such that the main electric charge and the compensation electric charge are opposite in polarity.