Abstract: A piezoelectric thin film resonator includes: a substrate; a piezoelectric film provided on the substrate; a lower electrode and an upper electrode that are opposed to each other to put at least a part of the piezoelectric film therebetween; and an insertion film that is inserted into the piezoelectric film in a resonance region where at least the part of the piezoelectric film is put between the lower electrode and the upper electrode, at least a part of the insertion film corresponding to an outer circumference region in the resonance region being thicker than a part of the insertion film corresponding to a central region in the resonance region.

Abstract: An acoustic wave device includes: a piezoelectric film made of an aluminum nitride film containing a divalent element and a tetravalent element, or a divalent element and a pentavalent element; and an electrode that excites an acoustic wave propagating through the piezoelectric film.

Abstract: A filter includes: a plurality of piezoelectric thin film resonators, each having a multilayered film including a lower electrode located on a substrate, a piezoelectric film located on the lower electrode, and an upper electrode located on the piezoelectric film so as to face the lower electrode, wherein at least two piezoelectric thin film resonators have thick film portions, in each of which the multilayered film is thicker in at least a part of an outer peripheral portion than in an inner portion of a resonance region in which the lower electrode and the upper electrode face each other across the piezoelectric film, and lengths of the thick film portions from edges of the resonance regions are different from each other in the at least two piezoelectric thin film resonators.

Abstract: An electronic circuit includes a plurality of duplexers that are coupled to an antenna terminal and have a pass band different from each other and a plurality of acoustic wave filters that are respectively coupled between the antenna terminal and the plurality of the duplexers, wherein filter characteristics of a first acoustic wave filter of the plurality of the acoustic wave filters are set so as to allow passage of a signal in both a pass band for transmitting and a pass band for receiving of a first duplexer of the plurality of the duplexers that is coupled to the first acoustic wave filter and suppress passage of a signal in both a pass band for transmitting and a pass band for receiving of a second duplexer of the plurality of the duplexers that is different from the first duplexer.

Abstract: A piezoelectric thin-film resonator includes: a substrate; a piezoelectric film having a lower piezoelectric film provided on the substrate and an upper piezoelectric film provided on the lower piezoelectric film; lower and upper electrodes that face each other through at least a part of the piezoelectric film; an interposed film that is interposed between the lower piezoelectric film and the upper piezoelectric film and is located in an outer circumferential part of a resonance region in which the lower and upper electrodes face each other through the piezoelectric film, the interposed film not being provided in a central part of the resonance region; an upper surface of the lower piezoelectric film having a first roughness in a region in which the interposed film is not provided and a second roughness in another region in which the interposed film is provided, the first roughness being smaller than the second roughness.

Abstract: An acoustic wave filter includes series resonators and parallel resonators that have a piezoelectric film on an identical substrate and have a lower electrode and an upper electrode, wherein: one of the series resonators and the parallel resonators have a temperature compensation film on a face of the lower electrode or the upper electrode that is opposite to the piezoelectric film in a resonance region, the compensation film having an elastic constant of a temperature coefficient of which sign is opposite to a sign of a temperature coefficient of an elastic constant of the piezoelectric film; and the other have an added film on the same side as the temperature compensation film on the lower electrode side or the upper electrode side compared to the piezoelectric film in the resonance region in the one of the series resonators and the parallel resonators.

Abstract: A piezoelectric thin-film resonator includes: a lower electrode provided on a substrate; a piezoelectric film that is provided on the lower electrode and includes at least two layers; an upper electrode that is provided on the piezoelectric film and has a region sandwiching the piezoelectric film with the lower electrode and facing the lower electrode; and an insulating film that is provided in a region in which the lower electrode and the upper electrode face each other and between each of the at least two layers, wherein an upper face of the insulating film is flatter than a lower face of the insulating film.

Abstract: A piezoelectric thin film resonator includes: a substrate; a piezoelectric film provided on the substrate; a lower electrode and an upper electrode that sandwich at least a part of the piezoelectric film and face with each other; and an inserted film that is inserted in the piezoelectric film, is provided on an outer circumference region in a resonance region in which the lower electrode and the upper electrode sandwich the piezoelectric film and face with each other, is not provided in a center region of the resonance region, and has a cutout in the resonance region.

Abstract: A piezoelectric thin-film resonator includes, a substrate, a piezoelectric film provided on the substrate, and a lower electrode and an upper electrode that face each other through the piezoelectric film. The piezoelectric film has an air space that is provided in at least part of an outer circumferential part of a resonance region in which the upper and lower electrodes face each other through the piezoelectric film and is not provided in a central part of the resonance region.

Abstract: A piezoelectric thin film resonator includes: a piezoelectric film provided on a substrate; a lower electrode and an upper electrode sandwiching at least a part of the piezoelectric film and facing with each other; and an inserted film that is inserted in the piezoelectric film, is provided in an outer circumference region of a resonance region and is not provided in a center region of the resonance region, wherein: an angle between an edge face of the lower electrode and a lower face of the lower electrode in the resonance region is an acute angle; and a width of the inserted film in the resonance region on a side for extracting the upper electrode from the resonance region is larger than another width of the inserted film in the resonance region on a side for extracting the lower electrode from the resonance region.

Abstract: An acoustic wave device including: a substrate; a piezoelectric film formed on the substrate; an lower electrode provided on a first surface of the piezoelectric film; an upper electrode provided on a second surface of the piezoelectric film opposite to the first surface; and a mass loading film having a first pattern and a second pattern in a resonance portion in which the lower electrode and the upper electrode face each other through the piezoelectric film, the first pattern having portions and the second pattern having portions interlinking the portions of the first pattern.

Abstract: An acoustic wave device includes: a piezoelectric thin film resonator including: a substrate; a lower electrode formed on the substrate; at least two piezoelectric films formed on the lower electrode; an insulating film sandwiched by the at least two piezoelectric films; and an upper electrode formed on the at least two piezoelectric films, wherein an area of the insulating film within a resonance region, in which the lower electrode and the upper electrode face each other across the at least two piezoelectric films, is different from an area of the resonance region.

Abstract: An acoustic wave device includes a main resonator and a sub resonator each having a substrate, a lower electrode provided on the substrate, a piezoelectric film provided on the lower electrode, and an upper electrode provided on an upper side of the piezoelectric film. A frequency control film is provided on an upper side of a resonance area in which the upper electrode and the lower electrode face each other in at least one of the main resonator and the sub resonator. The frequency control film has multiple convex patterns, and the convex patterns are arranged with a common pitch for spurious adjustment and with different areas in the main resonator and the sub resonator.

Abstract: A ladder type filter includes series resonators S1˜S4 connected in series between an input terminal In and an output terminal Out, parallel resonators P1˜P3 connected in parallel between the input terminal In and the output terminal Out, a resonator RP connected in series with the series resonators S1˜S4 between the input terminal and the output terminal, the resonator RP having a resonance frequency lower than resonance frequencies of the series resonators S1˜S4, and an inductor Lp connected in parallel with the resonator. According to the present ladder filter, signals having frequencies away from the pass band can be suppressed by an attenuation pole formed by the inductor. It is further possible to suppress the insertion loss in the pass band by the resonator.

Abstract: An acoustic wave device includes: a piezoelectric film located on a substrate; a lower electrode and an upper electrode facing each other across the piezoelectric film; a temperature compensation film located on a surface, which is opposite to the piezoelectric film, of at least one of the lower electrode and the upper electrode and having a temperature coefficient of elastic constant opposite in sign to a temperature coefficient of elastic constant of the piezoelectric film; and an additional film located on a surface of the temperature compensation film opposite to the piezoelectric film and having an acoustic impedance greater than an acoustic impedance of the temperature compensation film.

Abstract: A method of manufacturing an elastic wave device is provided with a lamination step of forming, on a substrate (1), a plurality of elastic wave devices, each of which includes a lower electrode (2), a piezoelectric film (3), and an upper electrode (4); a measuring step for measuring the operation frequency distribution of the elastic wave devices on the substrate (1); and an adjusting step for forming an adjusting region, in which the thickness of the elastic wave device is different from the thicknesses of other portions in a resonance portion of each elastic wave device, corresponding with the distribution of the operation frequencies. The adjusting region is formed so that the size of the area of the adjusting region of the resonator portion of each elastic wave device is different in accordance with the operation frequency distribution that is measured. Thus, the frequency characteristics of the elastic wave devices are easily adjusted by a small number of steps.

Abstract: The filter includes one or more series resonators and one or more parallel resonators. An inductance is connected in series to at least a parallel resonator of the parallel resonators, and a antiresonance frequency of the parallel resonator to which the inductance is connected in series is equal to or higher than that of the series resonators. The duplexer, the communication module and the communication device are provided with the filter.

Abstract: An acoustic wave device includes: a first piezoelectric thin film resonator including a first lower electrode, a first upper electrode and a first piezoelectric film sandwiched between the first lower and upper electrodes; a decoupler film provided on the first upper electrode; and a second piezoelectric thin film resonator provided on the decoupler film and including a second lower electrode, a second upper electrode and a second piezoelectric film sandwiched between the second lower and upper electrodes, wherein the first piezoelectric film and the second piezoelectric film comprise aluminum nitride and include an element increasing a piezoelectric constant of the aluminum nitride.

Abstract: A piezoelectric thin film resonator 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; and an insertion film that is inserted into the piezoelectric film, is located in at least a part of an outer periphery region in a resonance region in which the lower electrode and the upper electrode face each other across the piezoelectric film, and is not located in a center region of the resonance region.

Abstract: A piezoelectric thin film resonator includes: a substrate; a piezoelectric film located on the substrate; a lower electrode and an upper electrode located to sandwich the piezoelectric film; a load film formed from patterns in a resonance region in which the lower electrode and the upper electrode face each other across the piezoelectric film, wherein the patterns are formed so as to surround a center of the resonance region and intersect with a pathway extending from the center to an outer periphery of the resonance region.