Methods for forming a film bulk acoustic resonator (FBAR) are provided. In the method, formation of several mutually overlapped and hence connected sacrificial material layers above and under a resonator sheet facilitates the removal of the sacrificial material layers. Cavities left after the removal overlap at a polygonal area with non-parallel sides. This reduces the likelihood of boundary reflections of transverse parasitic waves causing standing wave resonance in the FBAR, thereby enhancing its performance in parasitic wave crosstalk. Further, according to the disclosure, the FBAR is enabled to be integrated with CMOS circuitry and hence exhibits higher reliability.

Aspects of the subject technology relate to electronic devices having microphones. An electronic device may include a microphone and a resonator for the microphone. The resonator may be formed in a device structure that is spatially separated from the microphone. The resonator may be formed in an interior wall of a housing of the electronic device, or in a support structure within an enclosure of the electronic device. A resonator and/or one or more damping features, may reduce a resonance effect, on the microphone, of a resonant cavity within the enclosure of the electronic device and adjacent the microphone.

Aspects of the subject technology relate to electronic devices having microphones. An electronic device may include a microphone and a resonator for the microphone. The resonator may be formed in a device structure that is spatially separated from the microphone. The resonator may be formed in an interior wall of a housing of the electronic device, or in a support structure within an enclosure of the electronic device. A resonator and/or one or more damping features, may reduce a resonance effect, on the microphone, of a resonant cavity within the enclosure of the electronic device and adjacent the microphone.

A resonator device includes a quartz crystal substrate, a resonator element including a first excitation electrode arranged on a first surface of the quartz crystal substrate, a second excitation electrode arranged on a second surface of the quartz crystal substrate in opposition to the first excitation electrode, and first and second pad electrodes that are arranged on the first surface and are coupled to the first and second excitation electrodes, a base including a substrate and first and second interconnects arranged on the substrate, a first bonding member bonding the first pad electrode to the first interconnect, and a second bonding member bonding the second pad electrode to the second interconnect. The first and second bonding members are arranged such that a first imaginary line that passes through a centroid of the resonator element and is parallel to an X axis is interposed between the first and second bonding members. An angle θ1 formed between the first imaginary line and a second imaginary line passing through the first bonding member and the second bonding member is 100°<θ1<140°.

A resonator device includes a quartz crystal substrate, a resonator element including a first excitation electrode arranged on a first surface of the quartz crystal substrate, a second excitation electrode arranged on a second surface of the quartz crystal substrate in opposition to the first excitation electrode, and first and second pad electrodes that are arranged on the first surface and are coupled to the first and second excitation electrodes, a base including a substrate and first and second interconnects arranged on the substrate, a first bonding member bonding the first pad electrode to the first interconnect, and a second bonding member bonding the second pad electrode to the second interconnect. The first and second bonding members are arranged such that a first imaginary line that passes through a centroid of the resonator element and is parallel to an X axis is interposed between the first and second bonding members. An angle θ1 formed between the first imaginary line and a second imaginary line passing through the first bonding member and the second bonding member is 100°<θ1<140°.

The invention provides a planarization method, which can make the local flatness of the product to be processed more uniform. The product has a cavity filled with oxide and includes a first electrode layer, a piezoelectric layer and a second electrode layer superposed on the cavity. The first electrode layer covers the cavity and includes a first inclined face around the first electrode layer, and the piezoelectric layer covers the first electrode layer and is arranged on the first electrode layer. The planarization method includes: depositing a passivation layer on the second electrode layer and etching the passivation layer completely until the thickness of the passivation layer is reduced to the required thickness.

The present disclosure provides a film piezoelectric acoustic resonator. The resonator includes an upper electrode, a piezoelectric layer and a lower electrode which are stacked sequentially from a top to a bottom. A projection of the effective resonance region along a direction of the piezoelectric layer is a hexagon. The hexagon has a first side with a longest length, a second side opposite to the first side, a third side with a shortest length, and a fourth side opposite to the third side. A portion of the upper electrode extending out of the effective resonance region through a first boundary of the effective resonance region is defined as an upper electrode led-out portion; a portion of the lower electrode extending out of the effective resonance region through a second boundary of the effective resonance region is defined as a lower electrode led-out portion.

The present disclosure provides a film piezoelectric acoustic resonator. The resonator includes an upper electrode, a piezoelectric layer and a lower electrode which are stacked sequentially from a top to a bottom. A projection of the effective resonance region along a direction of the piezoelectric layer is a hexagon. The hexagon has a first side with a longest length, a second side opposite to the first side, a third side with a shortest length, and a fourth side opposite to the third side. A portion of the upper electrode extending out of the effective resonance region through a first boundary of the effective resonance region is defined as an upper electrode led-out portion; a portion of the lower electrode extending out of the effective resonance region through a second boundary of the effective resonance region is defined as a lower electrode led-out portion.

A transducer includes first and second piezoelectric layers made of corresponding different first and second piezoelectric materials and three or more electrodes, implemented in two or more conductive electrode layers. The first piezoelectric layer is sandwiched between a first pair of electrodes and the second piezoelectric layer is sandwiched between a second pair of electrodes. The first and second pairs of electrodes contain no more than one electrode that is common to both pairs.

An acoustic wave device includes a piezoelectric film made of lithium niobate or lithium tantalate, first and second busbar electrodes located on the piezoelectric film and opposite to each other, and first and second electrode fingers and each including one end coupled to the first busbar electrode or the second busbar electrode. The acoustic wave device uses bulk waves in a first thickness-shear mode. A first gap is provided between the first busbar electrode and the second electrode finger. A second gap is provided between the second busbar electrode and the first electrode finger. A length of the first gap and the second gap in a direction in which the first and second electrode fingers extend is about 0.92p or longer, where p is a center-to-center distance between the adjacent first and second electrode fingers.