A piezoelectric thin film resonator includes: a substrate; a piezoelectric film that is located on the substrate; a lower electrode that is located on the substrate through an air gap, makes contact with the piezoelectric film, and includes a thin film part and a thick film part in which a distance from the air gap to a surface making contact with the piezoelectric film is greater than that of the thin film part in a region overlapping with the air gap in plan view; and an upper electrode that is located on an opposite surface of the piezoelectric film from a surface making contact with the lower electrode.

Acoustic wave devices are disclosed. An acoustic wave device can include a first filter and a second filter coupled to a common node. The second filter includes acoustic wave resonators of a first type (e.g., bulk acoustic wave resonators) and a series acoustic wave resonator of the second type (e.g., a surface acoustic wave resonator) that is coupled between the acoustic wave resonators of the first type and the common node. The acoustic wave device can further include a loop circuit coupled to the first filter, in which the loop circuit is configured to generate an anti-phase signal to a target signal at a particular frequency. In certain embodiments, the first filter is a receive filter and the second filter is a transmit filter.

An apparatus comprises a substrate, a dielectric disposed on the semiconductor substrate, an acoustic resonator disposed on the dielectric, and an electrical interconnect disposed in the dielectric and configured to transmit an electrical signal to or from at least one electrode of the acoustic resonator through a signal path disposed at least partially below a level of the acoustic resonator.

An acoustic resonator device includes a composite first electrode disposed over a substrate; a piezoelectric layer disposed on the composite first electrode, the piezoelectric layer including a piezoelectric material doped with scandium for improving piezoelectric properties of the piezoelectric layer; and a second electrode disposed on the piezoelectric layer. The composite first electrode includes a base electrode layer disposed over the substrate; a temperature compensation layer disposed on the base electrode layer; a seed interlayer disposed on the temperature compensation layer, the seed interlayer having a thickness between about 5 Å and about 150 Å; and a conductive interposer layer disposed on at least the seed interlayer, at least a portion of the conductive interposer layer contacting the base electrode layer. The piezoelectric layer has a negative temperature coefficient and the temperature compensation layer has a positive temperature coefficient that at least partially offsets the negative temperature coefficient of the piezoelectric layer.

A method of fabricating an electronic component includes forming a functional unit on a main surface of a substrate, forming a sacrificial layer covering the functional unit on the main surface, forming a cap layer covering the sacrificial layer, the cap layer forming a periphery enclosing the cavity on the main surface, forming holes through the cap layer, forming a cavity by removing the sacrificial layer using a wet etching process through the holes, the holes including a peripheral hole communicating an inside of the cavity with an outside of the cavity along the main surface, and forming a first resin layer covering the cap layer and the main surface.

A resonator element includes a vibrating portion that vibrates in a thickness shear vibration and includes a first main surface and a second main surface which are in a front and back relationship to each other, a first excitation electrode that is provided on the first main surface, and a second excitation electrode that is provided on the second main surface, and an energy trapping coefficient M satisfies a relationship of 33.6≦M≦65.1.

An acoustic wave device includes: a substrate; a piezoelectric film located on the substrate; a lower electrode and an upper electrode facing each other across at least a part of the piezoelectric film; a silicon oxide film located at an opposite side of at least one of the lower electrode and the upper electrode from the piezoelectric film; a non-oxygen-containing insulating film located between the at least one of the lower electrode and the upper electrode and the silicon oxide film; and an additional film located at an opposite side of the silicon oxide film from the non-oxygen-containing insulating film and made of a material different from a material of the silicon oxide film.

A bulk acoustic wave resonator (BAWR) includes a bulk acoustic resonance unit and at least one compensation layer. The bulk acoustic resonance unit includes a first electrode, a second electrode, and a piezoelectric layer disposed between the first electrode and the second electrode. The first electrode, the second electrode, and the piezoelectric layer each include a material that modifies a resonance frequency based on a temperature, and the at least one compensation layer includes a material that adjusts the resonance frequency modified based on the temperature in a direction opposite to a direction of the modification.

Two or more ME resonators are connected in series and in parallel generating a high sensitive, energy efficient and broadband miniature antenna and other conductor devices.

A piezoelectric thin film resonator includes: a substrate; a lower electrode located on the substrate; a piezoelectric film that has a step on an upper surface thereof and is located on the lower electrode, a film thickness of the piezoelectric film inside the step being greater than a film thickness of the piezoelectric film outside the step; an upper electrode located on the piezoelectric film so that a resonance region is formed, the lower electrode and the upper electrode facing each other across the piezoelectric film in the resonance region, the resonance region including the step in plan view; and an insertion film located in the piezoelectric film, between the piezoelectric film and the lower electrode, or between the piezoelectric film and the upper electrode in at least a part of an outer peripheral region within the resonance region, and not located in a central region of the resonance region.