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 film bulk acoustic wave resonator includes a first substrate; a first insulating material layer, formed on the first substrate; a first cavity, formed in the first insulating material layer with an opening facing away from the first substrate; and an acoustic-wave resonant plate, including a first electrode, a piezoelectric oscillation plate, and a second electrode stacked on the first insulating material layer. The piezoelectric oscillation plate is disposed between the first electrode and the first electrode. The first electrode includes a first electrode cavity above the first cavity. The second electrode includes a second cavity above the first cavity. At least a portion of a boundary of the piezoelectric oscillation plate is formed by a boundary of the first electrode cavity and a boundary of the second electrode cavity. The boundary of the piezoelectric oscillation plate has an irregular polygonal shape without having two parallel edges.

A bulk acoustic wave resonator with better performance and better manufacturability is described. The bulk acoustic wave resonator includes a composite piezoelectric film. The composite piezoelectric film includes a first sublayer of a first piezoelectric material, a second sublayer of a second piezoelectric material, and a third sublayer of a third piezoelectric material that is disposed between the first sublayer and the second sublayer. The first piezoelectric material has a first lattice constant, the second piezoelectric material has a second lattice constant, and the third piezoelectric material has a third lattice constant that is distinct from the first lattice constant and from the second lattice constant. The composite piezoelectric film may include a sequence of alternating sublayers of two or more distinct piezoelectric materials, or a sequence of composition graded layers having gradually changing composition.

A bulk acoustic (BAW) resonator having a multilayer base and method of fabricating the bulk acoustic resonator is disclosed. A BAW resonator comprises a substrate having a cavity and including a frame around the cavity, a multilayer base adjacent the cavity and supported by the frame. The multilayer base includes a first layer of crystalline material having a first lattice constant and a second layer of crystalline material having a second lattice constant that is distinct from the first lattice constant. The BAW resonator further includes a stack over the multilayer base. The stack includes a first electrode formed on the multilayer base, a piezoelectric layer having a first side coupled to the first electrode and a second side opposite to the first side of the piezoelectric layer, and a second electrode coupled to the second side of the piezoelectric layer.

A bulk acoustic wave (BAW) resonator with better performance and better manufacturability is described. A BAW resonator includes a substrate, a BAW stack disposed over the substrate, a first temperature compensation layer disposed between the substrate and the stack, and a second temperature compensation layer disposed over the stack. The BAW stack includes a piezoelectric layer disposed between a first electrode and a second electrode. A method of making a BAW resonator is also disclosed. The method includes forming a first base layer over a substrate including a layer of sacrificial material and a frame surrounding the layer of sacrificial material, forming a first temperature compensation layer over the first base layer, forming a BAW stack over the first temperature compensation layer, forming a second temperature compensation layer over the BAW stack, and removing the layer of sacrificial material to form a cavity adjacent the base layer.

A bulk acoustic wave (BAW) resonator includes a substrate, a stack over the substrate and including a piezoelectric layer disposed between two electrode layers, and one or more edge frames. The one or more edge frames can be a raised metal frame extending parallel to a periphery of an active region of the stack and has one or more slanted cuts such that the edge frame does not form a closed loop and loss of acoustic energy in the active region through the one or more cuts is reduced, minimized or prevented. Alternatively or additionally, the one or more edge frames include a recessed edge frame in the form of a trench in the piezoelectric layer extending parallel to a boundary of the active region, and may further include a second edge frame formed on the first electrode and embedded in the piezoelectric layer.

A bulk acoustic wave resonator includes: a first electrode; a piezoelectric layer disposed on at least a portion of the first electrode; and a second electrode disposed on the piezoelectric layer. The piezoelectric layer contains a dopant, and a value of [a thickness (nm) of the piezoelectric layer x a concentration (at %) of the dopant]/100 is less than or equal to 80.

A method and structure for 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. 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.

In a method of manufacturing a piezoelectric device in which a piezoelectric thin film on which functional conductors are formed is fixed to a support substrate by a fixing layer, an alignment mark is formed on one main surface of a light-transmitting piezoelectric substrate. A sacrificial layer is formed on a main surface of the piezoelectric substrate with reference to the alignment mark and the fixing layer is formed so as to cover the sacrificial layer and is bonded to the support substrate. The piezoelectric thin film is formed by being separated from the piezoelectric substrate and the functional conductors are formed on the surface of the piezoelectric thin film with reference to the alignment mark. The piezoelectric device is able to be manufactured while positions of formation regions of conductors are adjusted efficiently.

A method for producing an adjustable bulk acoustic wave resonator comprising a transducer stack (E1) and a tuning stack (E2). According to the invention, transducer stack (E1) includes two defined electrodes (4, 6) and piezoelectric material (2), and stack (E2) includes a layer of piezoelectric material (8) and two defined electrodes (10, 12). The method includes: a) production of the transducer stack; b) formation of an electrically insulating layer on an electrode (6) of the transducer stack; c) formation of a defined electrode (10) of the tuning stack on the electrically insulting layer such that it is aligned with the electrodes of the transducer stack; d) assembly, on the electrode (10), of a substrate of piezoelectric material; e) fracturing of the substrate of piezoelectric material; and f) formation of the other defined electrode (12) of the tuning stack, aligned with the defined electrode (10).