Laterally-excited bulk acoustic wave resonator and filter device including the same

A bandpass filter, comprising

• a plurality of acoustic resonators, at least one acoustic resonator of the plurality of acoustic resonators including:
• a substrate including a base and a cavity extending in a thickness direction thereof;
• and
• a piezoelectric layer coupled to the substrate, wherein the piezoelectric layer includes a plurality of nanowire structures that each comprise:
• a piezoelectric bar that extends in a first direction over the cavity, and
• a pair of electrodes, each electrode of the pair of electrodes disposed on an opposite side of the piezoelectric bar to sandwich the piezoelectric bar in a second direction that is substantially perpendicular to the first direction and substantially orthogonal to a thickness direction of the substrate,
• wherein at least two neighboring nanowire structures of the plurality of nanowire structures have a gap therebetween in the second direction.

A radio frequency module comprising:

• a filter device including a plurality of acoustic resonators;
• and
• a radio frequency circuit coupled to the filter device, the filter device and the radio frequency circuit being enclosed within a common package, wherein at least one acoustic resonator of the plurality of acoustic resonators of the filter device includes:
• a substrate including a base and a cavity extending in a thickness direction thereof;
• and
• a piezoelectric layer coupled to the substrate, wherein the piezoelectric layer includes a plurality of nanowire structures that each comprise:
• a piezoelectric bar that extends in a first direction over the cavity, and
• a pair of electrodes, each electrode of the pair of electrodes disposed on an opposite side of the piezoelectric bar to sandwich the piezoelectric bar in a second direction that is substantially perpendicular to the first direction and substantially orthogonal to a thickness direction of the substrate,
• wherein at least two neighboring nanowire structures of the plurality of nanowire structures have a gap therebetween in the second direction.