Abstract: To provide an elastic wave device that is small sized and in which a frequency fluctuation due to a change with time hardly occurs, and an electronic component using the above elastic wave device. A trapping energy mode portion 2 provided in an elastic wave waveguide 10 made of an elastic body material excites a second elastic wave being an elastic wave in an energy trapping mode by a specific frequency component included in a first elastic wave being an elastic wave in a first or higher-order propagation mode propagated from a first propagation mode portion 4, and a cutoff portion 3 provided in a peripheral region of the trapping energy mode portion 2 has a cutoff frequency being a frequency higher than that of the second elastic wave. A second propagation mode portion mode-converts the second elastic wave leaked through the cutoff portion to a third elastic wave being the elastic wave in the propagation mode to propagate the third elastic wave.

Abstract: A method for fabricating a quartz nanoresonator which can be integrated on a substrate, along with other electronics is disclosed. In this method a quartz substrate is bonded to a base substrate. The quartz substrate is metallized so that a bias voltage is applied to the resonator, thereby causing the quartz substrate to resonate at resonant frequency greater than 100 MHz. The quartz substrate can then be used to drive other electrical elements with a frequency equal to its resonant frequency. The quartz substrate also contains tuning pads to adjust the resonant frequency of the resonator. Additionally, a method for accurately thinning a quartz substrate of the resonator is provided. The method allows the thickness of the quartz substrate to be monitored while the quartz substrate is simultaneously thinned.

Abstract: To provide an elastic wave device that is small sized and in which a frequency fluctuation due to a change with time hardly occurs, and an electronic component using the above elastic wave device. A trapping energy mode portion 2 provided in an elastic wave waveguide 10 made of an elastic body material excites a second elastic wave being an elastic wave in an energy trapping mode by a specific frequency component included in a first elastic wave being an elastic wave in a zero-order propagation mode propagated from a first propagation mode portion 4, and a cutoff portion 3 provided in a peripheral region of the trapping energy mode portion 2 has a cutoff frequency being a frequency higher than that of the second elastic wave. A second propagation mode portion mode-converts the second elastic wave leaked through the cutoff portion to a third elastic wave being the elastic wave in the zero-order propagation mode to propagate the third elastic wave.

Abstract: A piezoelectric device including: a piezoelectric element having, on a surface of a piezoelectric body, an exciting electrode and a drawing electrode that is electrically coupled to the exciting electrode and draws an electrode to an external section, and a substrate bonded to the drawing electrode with a metallic brazing material, in that: the piezoelectric element contains a connecting electrode connecting the exciting electrode with the drawing electrode; and the connecting electrode and/or the exciting electrode contains an underlying layer provided on the surface of the piezoelectric body and a surface layer section provided on a surface of this underlying layer, wherein: the underlying layer is provided using the metallic brazing material and a metallic material of adverse wettability; and a portion of the surface layer section is removed in a manner that the exciting electrode and the drawing electrode are separated.

Abstract: A polymer bulk acoustic resonator that includes an active semiconductor layer, a first thin film electrode layer applied to the semiconductor layer, a thin film electro-active polymer layer applied to the first thin film electrode layer; and a second thin film electrode layer applied to the thin film electro-active polymer layer.

Abstract: A piezoelectric resonator includes a multi-layer top electrode configured such that a top most layer protects the underlying layers from subsequent etching, thereby preventing etch undercut of the top-most layer. In one embodiment, the multi-layer top electrode is configured as a bi-layer, so that the upper layer of the bi-layer stack protects all sides of the underlying layer from subsequent etch process steps. In an alternative embodiment, at least the perimeter of a multi-layer top electrode is completely covered with overlapping interconnect metal.

Abstract: A piezoelectric thin-film resonator includes: a lower electrode that is formed on a substrate; a piezoelectric film that is formed on the substrate and the lower electrode; an upper electrode that is formed on the piezoelectric film, with a portion of the piezoelectric film being interposed between the lower electrode and the upper electrode facing each other; and an additional film that is formed on the substrate on at least a part of the outer periphery of the lower electrode at the portion at which the lower electrode and the upper electrode face each other, with the additional film being laid along the lower electrode.

Abstract: Provided is an acoustic sensor for measuring a sound wave propagating through a gas such as air or a fluid such as water and an elastic wave propagating through a solid medium, and more particularly, an acoustic sensor with a piezo-arrangement film capable of detecting frequencies in a broad band or amplifying a signal at a specific frequency by comparting a waveguide into an upper waveguide and a lower waveguide by means of a compartment diaphragm and arranging piezoelectric sensors on the compartment diaphragm in several forms. The acoustic sensor can be utilized as a resonant acoustic sensor in which the piezoelectric sensors are arranged on the compartment diaphragm in the same form so that a signal at a specific frequency overlaps for high sensibility or a broadband acoustic sensor in which the piezoelectric sensors are arranged in a different form to detect frequencies in a broad band.

Abstract: An ultrasonic sensor is provided with a substrate unit where a thin-walled portion is arranged and a piezoelectric oscillator which is formed at the substrate unit. The piezoelectric oscillator includes two electrodes and a piezoelectric film positioned between the two electrodes. The thin-walled portion and the piezoelectric oscillator construct a membrane structure which will resonate at a predetermined frequency.

Abstract: A BAW device includes a semiconductor substrate with a surface region, an insulating layer formed on the surface region and a piezoelectric layer sandwiched by a first and second electrode, wherein the second electrode is formed on the insulating layer. The surface region is performed such that a voltage dependence of a capacitance between the substrate and the second electrode is substantially suppressed.

Abstract: A method of manufacturing an acoustic wave device includes: forming a conductive pattern on a wafer made of a piezoelectric substrate having an acoustic wave element, the conductive pattern including a first conductive pattern being continuously formed on a cutting region for individuating the wafer, a second conductive pattern being formed on an electrode region where a plated electrode is to be formed and being connected to the acoustic wave element and a third conductive pattern connecting the first conductive pattern and the second pattern; forming an insulating layer on the wafer so as to have an opening on the second conductive pattern; forming the plated electrode on the second conductive pattern by providing an electrical current to the second conductive pattern via the first conductive pattern and the third conductive pattern; and cutting off and individuating the wafer along the cutting region.

Abstract: A thin film piezoelectric resonator includes a substrate having a cavity; a first electrode extending over the cavity; a piezoelectric film placed on the first electrode; and a second electrode placed on the piezoelectric film, the second electrode having a periphery partially overlapping on the cavity and tapered to have an inner angle of 30 degrees or smaller defined by a part of the periphery thereof and a bottom thereof.

Abstract: A first supporting section provided between a substrate section and a second supporting section. The first supporting section is structured by, e.g., a film formed from a material having a higher acoustic impedance than a piezoelectric body and the substrate section, or a film formed from a material having a smaller Q value than the piezoelectric body and substrate section. By inserting the first supporting section, most vibration from the second supporting section toward the substrate section is reflected, and also a vibration having been transmitted to the substrate section from the second supporting section is prevented from reflecting at the bottom of the substrate section 40 and then returning in a direction of the vibration section.

Abstract: A piezoelectric resonator includes a resonator substrate, a base substrate supporting the resonator substrate, a lid substrate covering a surface of the resonator substrate, the surface being on an opposite side of a surface facing the base substrate, a first excitation electrode formed on the surface of the resonator substrate facing the lid substrate, a second excitation electrode formed on the surface of the resonator substrate facing the base substrate, and a third electrode provided on the surface of the resonator substrate facing the base substrate, the third electrode being electrically connected to the first excitation electrode through a concave portion which is formed on a side surface of the resonator substrate.

Abstract: An array of a plurality of ultrasonic transducers having a piezoelectric layer 2 and a couple of electrodes 7-1 and 7-2 sandwiching the piezoelectric layer therebetween is provided. The piezoelectric layer 2 has a first piezoelectric layer 2-1 provided on the ultrasonic-wave emission side, a second piezoelectric layer 2-2 provided on the other side of the first piezoelectric layer 2-1, and a common electrode 8 provided therebetween. Each of the ultrasonic transducers has a low-frequency response distribution that is uniform in the minor-axis direction perpendicular to a direction in which the ultrasonic transducers are arranged and a high high-frequency response distribution at a center part in the minor-axis direction. The characteristics of the minor-axis-direction frequency and sound pressure of the first piezoelectric layer are complemented by those of the second piezoelectric layer, whereby a uniform frequency characteristic for a minor-axis-direction low frequency is obtained.

Abstract: There is provided a piezoelectric vibrating reed, including: a base formed of a piezoelectric material and having a predetermined length; a plurality of vibrating arms extended from one side of the base; a support arm extended in a width direction from the other side spaced apart from the one side of the base by a predetermined interval and extended outside the vibrating arms in the same direction as the vibrating arms; and a cut portion formed of the piezoelectric material reduced in its width direction at a location closer to the vibrating arms than a connection portion where the support arms are connected to the base as one body, wherein a through-hole is also disposed at a location closer to the vibrating arms than the connection portion where the support arms are connected to the base as one body.

Abstract: A piezoelectric filter of the present invention is provided with first and second piezoelectric vibrators, each having a substrate, a lower load film formed on the substrate, a lower electrode formed on the lower load film, a piezoelectric element formed on the lower electrode, an upper electrode formed on the piezoelectric element and an upper load film formed on the upper electrode, and the piezoelectric filter is configured by electrically connecting the first and second piezoelectric vibrators to each other, and the piezoelectric element of the first piezoelectric vibrator and the piezoelectric element of the second piezoelectric vibrator correspond to respectively different areas of the same piezoelectric element; thus, the resonance frequencies of the first and second piezoelectric vibrators are adjusted by the respective lower load films and upper load films of the first piezoelectric vibrator and the second piezoelectric vibrator so that the resonance frequencies of the first and second piezoelectric

Abstract: Disclosed is a piezoelectric component (1) comprising a piezoelectric transducer (10) wherein a pair of electrodes (20a, 20b) are formed on both major surfaces of a piezoelectric substrate (11), a pair of frame members (30a, 30b) fitted to both major surfaces of the piezoelectric transducer (10), a pair of sealing substrates (40a, 40b) composed of a light-transmitting resin material and so fitted as to cover the frame members (30a, 30b), opaque coating layers (50a, 50b) respectively formed on the sealing substrates (40a, 40b), and a pair of input/output terminal electrodes (61a, 61b) respectively connected to the electrodes (20a, 20b). By having such a constitution, the state of sealed space and sealing widths of the frame members (30a, 30b) can be checked by visual examination such as direct visual observation or image recognition, and thus a highly reliable piezoelectric component (1) can be obtained. In addition, a mark can be made on the coating layers (50a, 50b).

Abstract: A piezoelectric resonator includes a laminated thin film having a first thin film portion supported by a substrate and a second thin film portion spaced apart from a first main surface of the substrate and acoustically isolated from the substrate. The second thin film portion of the laminated thin film includes a piezoelectric thin film, a first electrode disposed on the upper surface of the piezoelectric thin film, and a second electrode disposed on the lower surface of the piezoelectric thin film and being larger and thicker than the first electrode. The piezoelectric resonator further includes a mass adding film disposed around the first electrode and on at least one portion of a region extending outward from the periphery of a piezoelectric vibrating portion at which the first and second electrodes overlap each other with the piezoelectric thin film disposed therebetween.

Abstract: A piezoelectric thin-film resonator and a method of manufacturing thereof eliminate and prevent breaking of a piezoelectric thin film, disconnection of electrodes, and other known problems. The piezoelectric thin-film resonator includes a substrate and a suspended portion including a vibrating portion in which a piezoelectric thin film is disposed between a pair of excitation electrodes. At least two film-like supports partially supported on the substrate are provided. The suspended portion is supported by the supports so as to be suspended above the substrate with an air-gap layer therebetween.

Abstract: A sensor apparatus and method for detecting an environmental factor is shown that includes an acoustic device that has a characteristic resonant vibrational frequency and mode pattern when exposed to a source of acoustic energy and, further, when exposed to an environmental factor, produces a different resonant vibrational frequency and/or mode pattern when exposed to the same source of acoustic energy.

Abstract: A composite electronic component provided is one with sufficient impact resistance. In this resonator 1, a piezoelectric element 2 is supported by receivers 73, 83 in platelike holding portions 72, 82, and edge parts 74a, 84a in the holding portions 72, 82 are in contact with a capacitive element 3. This results in keeping the distance constant between the piezoelectric element 2 and the capacitive element 3. Furthermore, even if an impact is exerted on the resonator 1, the platelike holding portions 72, 82 will absorb the impact. Therefore, an improvement is made in impact resistance of the resonator 1.

Abstract: A piezoelectric resonator include a multi-layer top electrode. The multi-layer top electrode includes at least a top metal layer and a bottom metal layer. A top metal layer edge is recessed compared to a bottom metal layer edge allowing conformal deposition of a passivation layer. The passivation layer covers and protects the underlying layers from subsequent etching, thereby preventing etch undercut of the top electrode. In some embodiments, the multi-layer top electrode is configured as a bi-layer. In other embodiments, an extra layer is configured between the top metal layer and the bottom metal layer, for example a shunt load layer.

Abstract: A bulk wave acoustic resonant structure which is in accordance with the invention allows the difficulties encountered at high frequency, the impossibility of working at low frequency on simple structures and the absence of an adequate coupling level to be overcome. The invention therefore proposes the use of an additional layer of material which covers the upper electrode of a piezoelectric transducer in order to localize the position of maximum intensity of the dynamic stress close to the centre of the piezoelectric layer through the effect of propagation. The structure that is in accordance with the invention may be associated with Bragg mirrors and various uses are presented.

Abstract: A piezoelectric thin-film resonator includes: a lower electrode supported by a substrate, a space being defined below the lower electrode; a piezoelectric film provided on the lower electrode and the substrate; and an upper electrode provided on the piezoelectric film so as to form a resonance portion in which the upper electrode faces the lower electrode across the piezoelectric film. At least one of the lower electrode and the upper electrode has an interconnection portion used to extract a signal from the resonance portion and located above the space. The at least one of the lower electrode and the upper electrode has a first mass per unit area in which the at least one of the lower electrode and the upper electrode contacts the piezoelectric film and a second mass per unit area in the resonance portion. The first mass per unit area is smaller than the second mass per unit area.

Abstract: According to an exemplary embodiment, a bulk acoustic wave (BAW) resonator includes a piezoelectric layer situated between upper and lower electrodes, where each of the upper and lower electrodes are a high density metal. The BAW resonator further includes a controlled thickness region including a low density metal segment, where the low density metal segment is situated adjacent to the piezoelectric layer, and where the controlled thickness region has controlled electromechanical coupling. The controlled thickness region can provide reduced electromechanical coupling into lateral modes. The low density metal segment can extend along the perimeter of the BAW resonator.

Abstract: A suspended film bulk acoustic micro-resonator that includes a beam made of a piezoelectric material fixed to a support and sandwiched between excitation electrodes. The resonator also includes a mechanism modifying limiting conditions of the resonator composed of the excited beam to modify the micro-resonator resonant frequency.

Abstract: An energy-trapping strip piezoelectric vibrator utilizing a third harmonic overtone of a thickness shear mode is provided. A piezoelectric vibrator 1 has a strip piezoelectric ceramic substrate 2 polarized in a longitudinal direction, and first and second excitation electrodes 3 and 4 provided on first and second principal surfaces 2a and 2b of the piezoelectric ceramic substrate 2. An excitation region 5 including a piezoelectric vibration portion that includes a portion where the first and second excitation electrodes 3 and 4 overlap and that utilizes harmonics of the thickness shear mode is formed. A region around the piezoelectric vibration portion is set as a non-excitation region. At least a region of the non-excitation region neighboring the piezoelectric vibration portion is a region having the same polarization axis direction as the excitation region 5 and a relatively small polarization degree or is an unpolarized region.

Abstract: A piezoelectric thin-film resonator includes: a lower electrode that is formed on a substrate; a piezoelectric film that is formed on the lower electrode; and an upper electrode that is formed on the piezoelectric film. In the piezoelectric thin-film resonator, the upper electrode has a greater film thickness than the lower electrode.

Abstract: Methods of contacting the top layer in a BAW device by depositing a metal layer over the BAW device, patterning the metal layer so that the metal layer extends over and contacts the top electrode layer of the BAW device only at a plurality of spaced apart locations adjacent the periphery of the active resonator area, and has a common region laterally displaced from the top and bottom electrodes and electrically interconnecting the parts of the metal layer extending over and contacting the top electrode of the BAW device at the plurality of spaced apart locations.

Abstract: An energy trap piezoelectric resonator makes use of a harmonic wave in a thickness longitudinal vibration mode and can effectively suppress a spurious fundamental wave in a thickness longitudinal vibration mode without significantly suppressing the harmonic wave that is used for the resonator. The energy trap piezoelectric resonator has a first excitation electrode disposed at an upper surface of a piezoelectric substrate polarized in a thickness direction and a second excitation electrode disposed at a lower surface, and a floating electrode disposed at at least one of the upper surface and/or the lower surface of the piezoelectric substrate so as to extend towards and away from the first excitation electrode with respect to a node of an electric potential distribution based on electric charges generated by the fundamental wave that is propagated when an energy trap vibration portion where the excitation electrodes oppose each other is excited.

Abstract: Embodiments of the present invention provide a trapped acoustic wave system and a method of assembling such a system. The system may include a substrate having an acoustic wave cavity and a transducer mounted on the substrate. The transducer is configured to resonate the acoustic wave cavity. An acoustically transmissive adhesive secures a first portion of the transducer to the substrate. An additional adhesive, which is separate and distinct from the acoustically transmissive adhesive, anchors at least a second portion of the transducer to the substrate.

Abstract: A flexural resonator includes a piezoelectric material. At least a portion of an electrode having a first surface and a second surface is embedded in the piezoelectric material such that the piezoelectric material is disposed over and in electronic association with the first and second surfaces of the electrode.

Abstract: A thin film piezoelectric resonator includes: a substrate having a cavity; a first dielectric layer provided on the substrate to cover the cavity; a second dielectric layer provided on the substrate and disposed in a peripheral region of the cavity, and having a thickness larger than the first dielectric layer; a first electrode provided on the first dielectric layer and above the cavity; a piezoelectric layer provided on the first electrode and disposed to extend to a region on the second dielectric layer; and a second electrode provided on the piezoelectric layer and above the first electrode.

Abstract: Though the initial concept of the face-mounted resonator was ahead of fabrication technology, the solidly-mounted resonator (SMR) is now a practical resonator design yielding high Qs in a space-efficient and robust mounting configuration. An agile tunable piezoelectric SMR is now provided with a resonator and alternating stacks of high mechanical impedance and low mechanical impedance, piezoelectric layers advantageously stacked on a substrate with the piezoelectric layers connected to an adaptive circuit that alternates with an external electrical impedance having values anywhere between an open circuit and a short circuit.

Abstract: In a method for producing a boundary acoustic wave device that includes a first medium, a second medium, and a third medium laminated in that order, and electrodes disposed at the interface between the first medium and the second medium, the method includes the steps of preparing a laminate including the first medium, the second medium, and the electrodes disposed at the interface between the first medium and the second medium, adjusting the thickness of the second medium after the step of preparing the laminate to regulate a frequency or the acoustic velocity of a surface acoustic wave, a pseudo-boundary acoustic wave, or a boundary acoustic wave, after the adjusting step, forming the third medium different from the second medium in terms of the acoustic velocity with which the boundary acoustic wave propagates therethrough and/or in terms of material.

Abstract: Method for fabricating an acoustical resonator on a substrate having a top surface. First, a depression in said top surface is generated. Next, the depression is filled with a sacrificial material. The filled depression has an upper surface level with said top surface of said substrate. Next, a first electrode is deposited on said upper surface. Then, a layer of piezoelectric material is deposited on said first electrode. A second electrode is deposited on the layer of piezoelectric material using a mass load lift-off process.

Abstract: A filter includes multiple piezoelectric thin-film resonators each having a substrate, a lower electrode formed on the substrate, a piezoelectric film formed on the lower electrode, and an upper electrode provided on the piezoelectric film so that the upper electrode and the lower electrode face each other across the piezoelectric film. The multiple piezoelectric thin-film resonators include a first resonator in which at least a part of an outer curved portion of the piezoelectric film of the first resonator is located further out than an outer curved portion of a region in which the upper electrode and the lower electrode face each other across the piezoelectric film.

Abstract: A bulk acoustic wave resonator includes a resonator region having electrodes and a piezoelectric layer among the electrodes. The piezoelectric layer has a groove that bounds at least part of an electroacoustically active region of the piezoelectric layer. A depth of the groove is at least 50% of a thickness of the piezoelectric layer.

Abstract: There is provided a resonator having a piezoelectric ceramic resonator which has excellent free-fall resistance. The resonator comprises a piezoelectric ceramic resonator 2 with a vibrating electrode formed, and a substrate 3 which supports the piezoelectric ceramic resonator 2, wherein the piezoelectric ceramic resonator 2 satisfies the condition of U?0.88×H+20.28, wherein U=maximum elastic energy (kJ/m3) per unit volume, and H=drop height (m) (H>1). The present invention can be applied to a resonator 1, wherein the substrate 3 has terminal electrodes 31, 32, and the piezoelectric ceramic resonator 2 is in electrical continuity with the vibrating electrode and is supported on the substrate 3 at both ends via a conductive stator 4.

Abstract: In a piezoelectric resonator, a portion of a thin film unit is supported by a substrate. A portion of the thin film unit acoustically isolated from the substrate includes a) a vibration unit and b) an additional film. The vibration unit includes a piezoelectric film sandwiched between a pair of electrodes. The piezoelectric film is overlapped with the pair of electrodes in plan view. The additional film is disposed on one of the piezoelectric film and the electrodes so as to extend along at least a portion of the periphery of the vibration unit. When x (MN·second/m3) denotes an acoustic impedance of the additional film defined by the square root of the product of the density and Young's modulus, A denotes the product of the density and the thickness of the additional film, B denotes the product of the densities and the thicknesses of the electrodes, and y=A/B, the following conditional expressions are satisfied: In the range of 9.0?x<44.0, 0.0092·x+0.88?y<0.067·x+0.60??(1a) In the range of 44.

Abstract: Oscillators include a resonator having first and second electrodes and configured to resonate at a first frequency at which the first and second electrodes carry in-phase signals and at a second frequency at which the first and second electrodes carry out-of-phase signals. A driver circuit is configured to selectively sustain either the in-phase signals on the first and second electrodes or the out-of-phase signals on the first and second electrodes so that the resonator selectively resonates at either the first frequency or the second frequency, respectively. Related oscillator operating methods are also disclosed.

Abstract: A thin film piezoelectric resonator includes a substrate having a cavity, and a resonance portion located on the substrate and right above the cavity. The resonance portion includes a lower electrode layer located at a side of the cavity, an upper electrode layer opposite to the lower electrode layer, and a piezoelectric thin film located between the upper electrode layer and the lower electrode layer. A side of the piezoelectric thin film and a side of the lower electrode layer are located in a common plane.

Abstract: A resonator includes a piezoelectric thin-film provided on a main surface of a substrate, a first electrode film provided on a first surface of the piezoelectric thin-film, a second electrode film provided on a second surface of the piezoelectric thin-film, a frequency adjustment film provided on one of the first and second electrode films, the frequency adjustment film comprising a film laminate including a first adjustment film provided on said one of the first and second electrode films, and a second adjustment film provided on the first adjustment film. The first adjustment film is used for ?f adjustment, and the second adjustment film is used for correcting frequency deviations generated in the filter manufacturing process. Thus, it is possible to accurately control the center frequency of the filter in which the multiple resonators are connected.

Abstract: An object of the present invention is to provide an inexpensive thin film piezoelectric bulk acoustic wave resonator that allows fine-tuning of a resonant frequency. Another object is to provide an inexpensive filter with dramatically improved frequency characteristics, using thin film piezoelectric bulk acoustic wave resonators that can be formed on one substrate.

Abstract: A polymer bulk acoustic resonator that includes an active semiconductor layer, a first thin film electrode layer applied to the semiconductor layer, a thin film electro-active polymer layer applied to the first thin film electrode layer; and a second thin film electrode layer applied to the thin film electro-active polymer layer.

Abstract: A piezoelectric thin-film resonator includes a lower electrode formed on a substrate to define a rounded dome-shaped cavity between the lower electrode and the substrate, a piezoelectric film provided on the lower electrode, and an upper electrode provided on the piezoelectric film. A membrane region is an overlapping region of the lower electrode and the upper electrode interposing the piezoelectric film and a projected area of the cavity onto the substrate includes the membrane region.

Abstract: A piezoelectric resonator element and method of manufacturing same are provided. The piezoelectric resonator element having a lower electrode, a piezoelectric substance layer, and an upper electrode disposed in this order on a substrate with an air layer between the substrate and the lower electrode, and having a laminated structure of the lower electrode, the piezoelectric substance layer, and the upper electrode in at least a part of the piezoelectric resonator element, wherein internal stress of the piezoelectric substance layer is ?300 MPa to 90 MPa.

Abstract: An energy-trapping-type thickness extensional piezoelectric resonator using a thickness extensional vibration mode having first and second resonance electrodes formed on portions of the top surface and the bottom surface of a piezoelectric substrate that is polarized in the thickness direction thereof, respectively, in which a portion where the first and second resonance electrodes oppose each other is formed as an energy-trapping-type vibration section, wherein, in order to suppress frequency changes of the thickness extensional vibration mode due to temperature, which is a main response using resonance characteristics, a suppression response having a frequency-temperature-change tendency for suppressing frequency changes of the main response due to temperature is brought into close proximity with the main response.

Abstract: A film bulk acoustic resonator includes a substrate having a cavity at a surface of the substrate; a bottom electrode provided on the surface of the substrate so as to extend over the cavity; a piezoelectric film disposed on the bottom electrode; a top electrode disposed on the piezoelectric film so as to face the bottom electrode and extending over the surface of the substrate; and a seal member configured to seal a capacitor defined by the bottom electrode, the piezoelectric film and the top electrode, and to provide an opening portion of the cavity outside the seal member at the surface of the substrate.