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.

The present disclosure provides a film bulk acoustic resonator and its fabrication method. The film bulk acoustic resonator includes a first substrate, a first support layer containing a first cavity, a piezoelectric stacked layer, and a first separation structure and/or a second separation structure. The piezoelectric stacked layer includes an effective working region and a parasitic working region; and in the parasitic working region, a first electrode and a second electrode have a corresponding region along a thickness direction. The first separation structure separates the first electrode, and the first electrode of a portion of the parasitic working region is insulated from the first electrode of the effective working region; and the second separation structure separates the second electrode, and the second electrode of a portion of the parasitic working region is insulated from the second electrode of the effective working region.

A BAW resonator with an improved lateral energy confinement is provided. The resonator has a bottom electrode in a bottom electrode layer, a top electrode in a top electrode layer and a piezoelectric layer between the bottom electrode layer and the top electrode layer. The piezoelectric layer comprises piezoelectric materials of different piezoelectric polarities.

The application discloses a resonator and a semiconductor device. 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. The cavity is delimited by an upper surface of the substrate and a lower surface of the multilayer structure. A middle region of a part, corresponding to the cavity, of the lower surface of the multilayer structure is a plane. A smooth curved surface for smooth transition is between an edge of the middle region and an edge of the cavity, and the smooth curved surface is between the upper surface of the substrate and the plane.

Techniques are disclosed for forming integrated circuit single-flipped resonator devices that include an electrode formed of a two-dimensional electron gas (2DEG). The disclosed resonator devices may be implemented with various group III-nitride (III-N) materials, and in some cases, the 2DEG may be formed at a heterojunction of two epitaxial layers each formed of III-N materials, such as a gallium nitride (GaN) layer and an aluminum nitride (AlN) layer. The 2DEG electrode may be able to achieve similar or increased carrier transport as compared to a resonator device having an electrode formed of metal. Additionally, in some embodiments where AlN is used as the piezoelectric material for the resonator device, the AlN may be epitaxially grown which may provide increased performance as compared to piezoelectric material that is deposited by traditional sputtering techniques.

Bulk acoustic wave resonators of two or more different filters can be on a common die. The two filters can be included in a multiplexer, such as a duplexer, or implemented as standalone filters. With bulk acoustic wave resonators of two or more filters on the same die, the filters can be implemented in less physical space compared to implementing the same filters of different die. Related methods, radio frequency systems, radio frequency modules, and wireless communication devices are also disclosed.

Bulk acoustic wave resonators of two or more different filters can be on a common die. The two filters can be included in a multiplexer, such as a duplexer, or implemented as standalone filters. With bulk acoustic wave resonators of two or more filters on the same die, the filters can be implemented in less physical space compared to implementing the same filters of different die. Related methods, radio frequency systems, radio frequency modules, and wireless communication devices are also disclosed.

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 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 lower electrode disposed on the substrate; a piezoelectric layer disposed to cover at least a portion of the lower electrode; an upper electrode disposed to cover at least a portion of the piezoelectric layer; and a passivation layer disposed to cover at least a portion of the upper electrode, wherein the passivation layer includes a non-trimming-processed portion disposed outside an active region of the bulk acoustic wave resonator in which portions of the lower electrode, the piezoelectric layer, and the upper electrode overlap, and having a thickness that is thicker than a thickness of a portion of the passivation layer disposed in the active region.