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 acoustic resonator comprises a substrate, a resonant portion disposed on the substrate and in which a first electrode, a piezoelectric layer, and a second electrode are stacked, a protective layer disposed on an upper portion of the resonant portion, and a hydrophobic layer formed on the protective layer, and the protective layer comprises a first protective layer stacked on the second electrode and a second protective layer stacked on the first protective layer, wherein a density of the second protective layer is higher than a density of the first protective layer.

A bulk-acoustic wave resonator includes a substrate, a first layer, a second layer, a membrane layer, and a resonance portion. The substrate includes a substrate protection layer. The first layer is disposed on the substrate protection layer. The second layer is disposed outside of the first layer. The membrane layer forms a cavity with the substrate protection layer and the first layer. The resonance portion is disposed on the membrane layer. Either one or both of the substrate protection layer and the membrane layer includes a protrusion disposed in the cavity.

An electronic component housing package includes a base having a first principal face provided with a mounting section for mounting an electronic component; a frame having a second principal face, the frame being disposed on the base so as to surround the mounting section; a frame-shaped metallized layer disposed on the second principal face of the frame; and a side-surface conductor disposed on an inner side surface of the frame, the side-surface conductor connecting the frame-shaped metallized layer and a relay conductor formed on the first principal face, the side-surface conductor being covered with an insulating film from one end to the other end in a width direction of the side-surface conductor.

A vibrator device including a vibrator element, an IC substrate including a semiconductor substrate configured of a semiconductor having a first conductive type and a circuit electrically coupled to the vibrator element, the first conductive type being any one of an N-type and a P-type, and a lid directly bonded to the semiconductor substrate and configured of a semiconductor having the first conductive type.

An acoustic wave device includes a piezoelectric layer made of lithium niobate or lithium tantalate, and first and second electrodes opposed to each other in a direction that intersects with a thickness direction of the piezoelectric layer. The first and second electrodes are adjacent electrodes, and, when a thickness of the piezoelectric layer is d and a distance between centers of the first and second electrodes is p, d/p is less than or equal to about 0.5.

An acoustic wave device includes a piezoelectric layer, at least one pair of electrodes adjacent to each other, and an additional film. The piezoelectric layer is made of lithium niobate or lithium tantalate, and includes first and second opposing principal surfaces. The at least one pair of electrodes is located on the first principal surface of the piezoelectric layer. The additional film is located on the piezoelectric layer or either one or both of the electrodes so as to overlap, in plan view, either one or both of areas in which the electrodes are located and an area between the electrodes. When d represents a thickness of the piezoelectric layer and p represents a center-to-center distance between the electrodes, d/p is equal to or less than about 0.5.

An acoustic wave device includes a high-acoustic-velocity film, a low-acoustic-velocity film, a piezoelectric layer including lithium tantalate, and an IDT electrode on the piezoelectric layer. The IDT electrode includes first and second busbars and first and second electrode fingers. An intersecting region is a portion where the first and second electrode fingers overlap in an acoustic wave propagation direction. The intersecting region includes a central region and first and second edge regions. The IDT electrode includes first and second gap regions outside the first and second edge regions. The first and second electrode fingers are wider in the first and second edge regions than in the central region. A duty ratio in the first and second edge regions is from about 0.62 to about 0.73.

A micromechanical system (MEMS) acoustic wave resonator is formed on a base substrate. A piezoelectric member is mounted on the base substrate. The piezoelectric member has a first electrode covering a first surface of the piezoelectric member and a second electrode covering a second surface of the piezoelectric member opposite the first electrode, the second electrode being bounded by a perimeter edge. A first guard ring is positioned on the second electrode spaced apart from the perimeter edge of the second electrode.

Embodiments of this disclosure relate to acoustic wave filters configured to filter radio frequency signals. An acoustic wave filter includes a first bulk acoustic wave resonator on a substrate, a second bulk acoustic wave resonator on the substrate, a conductor electrically connecting the first bulk acoustic wave resonator in anti-series with the second bulk acoustic wave resonator, and an air gap positioned between the conductor and a surface of the substrate. The air gap can reduce parasitic capacitance associated with the conductor. Acoustic wave filters disclosed herein can suppress a second harmonic.