Acoustic resonators, filters, and methods. A filter includes a piezoelectric plate supported by a substrate; and three or more diaphragms of the piezoelectric plate spanning a respective cavity in the substrate. A conductor pattern on the plate has interdigital transducers (IDTs) of three or more acoustic resonators. Each IDT has two sets of interleaved fingers extending from two busbars respectively. Overlapping portions of the fingers define an aperture of each acoustic resonator. Sometimes, each of the resonators has two dielectric strips that overlap the IDT fingers in first and second margins of the aperture and that extend into first and second gaps between the first and second margins and the busbars. Other times, the first and second dielectric strips are on the front surface of the plate, have a first portion under the IDT fingers and have a second portion extending into a gap between the margins and the busbars.

A micro-resonator includes a first electrode positioned on a piezoelectric plate at a first end of the piezoelectric plate, the first electrode including a first set of fingers and a second electrode positioned on the piezoelectric plate at a second end of the piezoelectric plate. The second electrode including a second set of fingers interdigitated with the first set of fingers with an overlapping distance without touching the first set of fingers, the overlapping distance being less than seven-tenths the length of one of the first set of fingers or the second set of fingers. At least one of the first end or the second end of the piezoelectric plate may define a curved shape.

A thin-film bulk acoustic resonator, a semiconductor apparatus including the acoustic resonator and its manufacturing method are presented. The thin-film bulk acoustic resonator includes a lower dielectric layer, a first cavity inside the lower dielectric layer, an upper dielectric layer, a second cavity inside the upper dielectric layer, and a piezoelectric film that is located between the first and second cavities and continuously separates these two cavities. The plan views of the first and the second cavities have an overlapped region, which is a polygon that does not have any parallel sides. The piezoelectric film of this inventive concept is a continuous film without any through-hole in it, therefore it can offer improved acoustic resonance performance.

RF filtering circuitry comprises a first node, a second node, and a series signal path between the first node and the second node. A number of acoustic resonators are coupled to one or more of the first node and the second node via the series signal path. A first one of the acoustic resonators is associated with a first quality factor and a first electromechanical coupling coefficient. A second one of the acoustic resonators is associated with a second quality factor and a second electromechanical coupling coefficient. The first quality factor is different from the second quality factor and the first electromechanical coupling coefficient is different from the second electromechanical coupling coefficient.

Acoustic resonators, filters, and methods. An acoustic resonator includes a substrate, a piezoelectric plate, and a diaphragm including a portion of the piezoelectric plate spanning a cavity in a substrate. An interdigital transducer (IDT) on a front surface of the piezoelectric plate includes first and second sets of interleaved interdigital transducer (IDT) fingers extending from first and second busbars respectively. The interleaved IDT fingers extend onto the diaphragm. Overlapping portions of the interleaved IDT fingers define an aperture of the acoustic resonator. First and second dielectric strips are on the front surface of the piezoelectric plate. Each dielectric strip has a first portion under the IDT fingers in a respective margin of the aperture and a second portion extending into a gap between the respective margin and the respective busbar.

An elastic wave device in which a recess is provided on an upper side of a support, a piezoelectric thin film covers the recess, and an IDT electrode is provided on an upper surface of the piezoelectric thin film. A plate wave of an S0 mode or SH0 mode is used. A plurality of grooves are provided in the upper surface or lower surface of the piezoelectric thin film at a portion of the piezoelectric thin film that is positioned on a hollow section.

A multi-stage matching network filter circuit device. The device comprises bulk acoustic wave (BAW) resonator device having an input node, an output node, and a ground node. A first matching network circuit is coupled to the input node. A second matching network circuit is coupled to the output node. A ground connection network circuit coupled to the ground node. The first or second matching network circuit can include an inductive ladder network including a plurality of series inductors in a series configuration and a plurality of grounded inductors wherein each of the plurality of grounded inductors is coupled to the connection between each connected pair of series inductors. The inductive ladder network can include one or more LC tanks, wherein each of the one or more LC tanks is coupled between a connection between a series inductor and a subsequent series inductor, which is also coupled to a grounded inductor.

Acoustic resonator devices and methods are disclosed. An acoustic resonator device includes a substrate having a front surface and an intervening oxide layer on the front surface and having a cavity. A thickness of the intervening oxide layer defines a depth of the cavity, and the substrate has vertical etch-stop material for etching the intervening oxide layer. Lateral fences formed in the intervening oxide layer define a perimeter of the cavity. The lateral fences has a lateral etch-stop material for etching the intervening oxide layer. A single-crystal piezoelectric plate has a back surface attached to the front surface of the intervening oxide layer except for a portion of the piezoelectric plate forming a diaphragm that spans the cavity. An interdigital transducer is formed on the front surface of the single-crystal piezoelectric plate such that interleaved fingers of the IDT are disposed on the diaphragm.

A filter includes a series resonator including a first piezoelectric layer and first electrodes, and a parallel resonator including a second piezoelectric layer and second electrodes. Each of the first and second piezoelectric layers is a monocrystalline lithium niobate layers, has an X-axis orientation in a planar direction, and has a thickness direction in a direction obtained by a 105° rotation of a +Z-axis orientation toward a +Y-axis orientation. The first electrodes face each other across the first piezoelectric layer to form a first resonance region and are extracted from the first resonance region in a direction substantially parallel to the X-axis orientation of the first piezoelectric layer. The second electrodes face each other across the second piezoelectric layer to form a second resonance region and are extracted from the second resonance region in a direction substantially orthogonal to the X-axis orientation of the second piezoelectric layer.

A bulk acoustic wave filter includes: a first bulk acoustic wave resonator including, in an order from bottom to top, a first cavity, a first bottom electrode, a first segment of a piezoelectric layer, and a first top electrode; a second bulk acoustic wave resonator disposed adjacent to the first bulk acoustic wave resonator, and including, in the order from bottom to top, a second cavity, a second bottom electrode, a second segment of the piezoelectric layer, and a second top electrode; a boundary structure surrounding the first cavity and the second cavity, the boundary structure including a boundary portion extending between and separating the first cavity and the second cavity, and the boundary portion being disconnected at a disconnection region; and a first release hole formed in the piezoelectric layer, and overlapping the disconnection region.