Abstract: An elastic wave device includes a supporting substrate, a high-acoustic-velocity film stacked on the supporting substrate and in which an acoustic velocity of a bulk wave propagating therein is higher than an acoustic velocity of an elastic wave propagating in a piezoelectric film, a low-acoustic-velocity film stacked on the high-acoustic-velocity film and in which an acoustic velocity of a bulk wave propagating therein is lower than an acoustic velocity of a bulk wave propagating in the piezoelectric film, the piezoelectric film is stacked on the low-acoustic-velocity film, and an IDT electrode stacked on a surface of the piezoelectric film.

Abstract: A piezoelectric device includes a base portion and a membrane portion. The membrane portion is indirectly supported by the base portion, and is located on the upper side relative to the base portion. The membrane portion includes a plurality of layers. The membrane portion does not overlap with the base portion, and includes a single crystal piezoelectric layer, an upper electrode layer, and a lower electrode layer. The membrane portion is provided with a through-groove penetrating in the up-down direction. The through-groove includes a first step portion provided in the thickest layer among the plurality of layers defining the membrane portion. The width of the through-groove is narrower on a lower side than on an upper side with the first step portion as a boundary.

Abstract: An ultrasonic Lamb wave transducer for non-invasive measurement and for emitting and/or receiving an ultrasonic Lamb wave pulse, an emission and a reception of the ultrasonic Lamb wave having an emission direction and a reception direction, respectively, the ultrasonic Lamb wave pulse being defined by at least one parameter, includes: at least one piezocomposite actuator for controlling the emission direction of the ultrasonic Lamb wave by emitting acoustic radiation at frequencies that are appropriate for generating ultrasonic Lamb waves.

Abstract: The disclosure provides a resonator and a filter. The resonator includes: a substrate; and a multilayer structure formed on the substrate. The multilayer structure successively includes a lower electrode layer, a piezoelectric layer and an upper electrode layer from bottom to top. A cavity is formed between the substrate and the multilayer structure, and the cavity includes a lower half cavity below an upper surface of the substrate and an upper half cavity beyond the upper surface of the substrate and protruding toward the multilayer structure. A resonator with novel structure and good performance is formed by providing the cavity with the lower half cavity below the upper surface of the substrate and the upper half cavity above the upper surface of the substrate.

Abstract: An energy transmission system for a fluid line having a generator unit with a power supply unit that can be arranged at a first location of the fluid line and at least one consumer unit having at least one consumer that can be arranged at a second location of the fluid line spaced apart from the first location is disclosed. The generator unit has a pressure surge generator connected to the power supply unit and the pressure surges can be generated and introduced into the fluid located in the fluid line, and the consumer unit has a pressure surge transducer that is connected to the at least one consumer by the pressure surges introduced into the fluid and can be converted into electrical energy that can be supplied to the at least one consumer.

Abstract: An acoustic transducer (30), comprising: a support structure (36); an active assembly comprising a base plate (32) supported by the support structure (36) and a piezoelectric body (34) supported by the base plate (32); and a passive vibrator (38) supported by the support structure (36) and coupled via the support structure (36) to the active assembly (32, 34) so that vibration of the active assembly (32, 34) drives the passive vibrator (38). The active assembly (32, 34) and the passive vibrator (38) have the same resonant frequency.

Abstract: An electronic device includes a substrate layer having a front surface and a back surface opposite the front surface, a plurality of ultrasonic transducers formed on the front surface of the substrate layer, wherein the plurality of ultrasonic transducers generate backward waves during operation, the backward waves propagating through the substrate layer, and a plurality of substrate structures formed within the back surface of the substrate layer, the plurality of substrate structures configured to modify the backward waves during the operation.

Abstract: An elastic wave device includes a supporting substrate, a high-acoustic-velocity film stacked on the supporting substrate and in which an acoustic velocity of a bulk wave propagating therein is higher than an acoustic velocity of an elastic wave propagating in a piezoelectric film, a low-acoustic-velocity film stacked on the high-acoustic-velocity film and in which an acoustic velocity of a bulk wave propagating therein is lower than an acoustic velocity of a bulk wave propagating in the piezoelectric film, the piezoelectric film is stacked on the low-acoustic-velocity film, and an IDT electrode stacked on a surface of the piezoelectric film.

Abstract: The invention relates to a test kit which is designed for bioanalysis, in particular for an immunoassay. The test kit comprises at least one measuring sensor (M) for the quantitative detection of a substance and at least one reference sensor (R1, R2, R3) which is already supplied with the substance in a defined manner. In the method for analyzing a test kit, the measuring sensor (M) is read and a measurement value for a concentration, a substance quantity, or a mass is obtained, wherein the read value of the at least one measuring sensor (M) is scaled using the read values of the at least one reference sensor (R1, R2, R3), or a measured value which corresponds to the read value is obtained by means of a compensation curve which puts the read values of the reference sensors (R1, R2, R3) into relationship with the defined supply of the substance to the reference sensors (R1, R2, R3).

Abstract: A piezoelectric element that includes a substrate, a lower electrode layer on the substrate, an intermediate layer on the lower electrode layer, and an upper electrode layer on the intermediate layer. The intermediate layer includes a first piezoelectric layer including an aluminum nitride as a main component thereof and located between the lower electrode layer and the upper electrode layer, a first buffer layer including an aluminum nitride as a main component and located between the first piezoelectric layer and the upper electrode layer, a first intermediate electrode layer located between the first buffer layer and the upper electrode layer, and a second piezoelectric layer located between the first intermediate electrode layer and the upper electrode layer.

Abstract: A method for de-icing or anti-icing an aircraft portion having at least one piezoelectric element fastened on the inner face of the aircraft portion includes, during a design phase of the aircraft portion, placing the piezoelectric element on an area of the aircraft portion to determine frequencies of resonance and increased dynamic coupling, and during the de-icing or anti-icing of the aircraft portion, the same piezoelectric element is excited according to the natural frequencies of the area.

Abstract: A loudspeaker unit for a portable device includes an electrodynamic loudspeaker configured as a woofer. The loudspeaker unit additionally includes a MEMS loudspeaker configured as a tweeter. A portable device includes the loudspeaker unit.

Abstract: An apparatus for producing haptic feedback and an electronic device are disclosed. In an embodiment an apparatus includes a piezoelectric actuator and a mechanical structure, wherein the piezoelectric actuator is configured to modify its extension in a first direction, and wherein the mechanical structure is configured to deform as a result of a change in the extension of the piezoelectric actuator in such a way that an area of the mechanical structure is moved in relation to the piezoelectric actuator in a second direction which is perpendicular to the first direction.

Abstract: A method for preparing a film bulk acoustic wave device by using a film transfer technology includes: 1) providing an oxide monocrystal substrate; 2) implanting ions from the implantation surface into the oxide monocrystal substrate, and then forming a lower electrode on the implantation surface; or vice versa; and forming a defect layer at the preset depth; 3) providing a support substrate and bonding a structure obtained in step 2) with the support substrate; 4) removing part of the oxide monocrystal substrate along the defect layer so as to obtain an oxide monocrystal film, and transferring the obtained oxide monocrystal film and the lower electrode to the support substrate; 5) etching the support substrate from a bottom of the support substrate to form a cavity; 6) forming an upper electrode on the surface of the oxide monocrystal film.

Abstract: Techniques are disclosed for forming high frequency film bulk acoustic resonator (FBAR) devices using epitaxially grown piezoelectric films. In some cases, the piezoelectric layer of the FBAR may be an epitaxial III-V layer such as an aluminum nitride (AlN) or other group III material-nitride (III-N) compound film grown as a part of a III-V material stack, although any other suitable piezoelectric materials can be used. Use of an epitaxial piezoelectric layer in an FBAR device provides numerous benefits, such as being able to achieve films that are thinner and higher quality compared to sputtered films, for example. The higher quality piezoelectric film results in higher piezoelectric coupling coefficients, which leads to higher Q-factor of RF filters including such FBAR devices. Therefore, the FBAR devices can be included in RF filters to enable filtering high frequencies of greater than 3 GHz, which can be used for 5G wireless standards, for example.

Abstract: The present disclosure relates to a high-pitched loudspeaker, which widens the starting frequency of the high-pitched loudspeaker, and the high-pitched loudspeaker has a smoother intermediate frequency curve and less distortion. A high-pitched loudspeaker comprises a magnetic circuit system, a voice coil, and a diaphragm connected to the voice coil, wherein a first cavity is formed between the magnetic circuit system and the voice coil and the diaphragm, the high-pitched loudspeaker further comprises a back cover, the magnetic circuit system is arranged between the diaphragm and the back cover, and a second cavity is formed between the back cover and the magnetic circuit system, a through-hole is opened on the magnetic circuit system which communicates the first cavity and the second cavity to constitute an air gap cavity of the high-pitched loudspeaker.

Abstract: An acoustic wave device that includes a spinel layer, a piezoelectric layer, a temperature compensating layer between the spinel layer and the piezoelectric layer and an interdigital transducer electrode on the piezoelectric layer is disclosed. The piezoelectric layer is disposed between the interdigital transducer electrode and the spinel layer. The acoustic wave device is configured to generate an acoustic wave having a wavelength of ?. The piezoelectric layer can have a thickness that is less than ?. In some embodiments, the spinel layer can be a polycrystalline spinel layer.

Abstract: An acoustic transducer includes a first flexible structure having a top surface and a bottom surface. A transducer is attached to the top surface of the first flexible structure, wherein the transducer causes deformation of the first flexible structure when an input electrical signal is applied to the transducer. A second flexible structure has a convex top surface and a concave bottom surface. The convex top surface of the second flexible structure is in contact with the bottom surface of the first flexible structure. Deformation of the first flexible structure causes deformation of the second flexible structure.

Abstract: An acoustic resonator includes a piezoelectric stack including a piezoelectric layer having a top surface and a bottom surface, a top electrode layer disposed above the top surface, and a bottom electrode layer disposed below the bottom surface. A number of acoustic wave reflectors are disposed on a side of the bottom electrode layer opposite the piezoelectric layer. Each acoustic wave reflector includes a high acoustic impedance layer and may include a low acoustic impedance layer. The acoustic resonator may include a tether that extends laterally to a stacking direction of the layers of the piezoelectric stack. A supporting structure may be coupled to the tether opposite the acoustic resonator for anchoring the acoustic resonator. A mirror, one or more phononic crystals, or both may be positioned on proximate the tether opposite the acoustic resonator to avoid resonant waves from exiting the acoustic resonator in use.

Abstract: A semiconductor device and a manufacturing method thereof are provided. The semiconductor device includes a substrate, a transistor and a heat dissipation structure. The substrate includes first and second semiconductor layers, and includes an insulating layer disposed between the first and second semiconductor layers. The substrate has a recess extending into the insulating layer from a surface of the first semiconductor layer. The transistor includes a hetero-junction structure, a gate electrode, a drain electrode and a source electrode. The hetero-junction structure is disposed on the second semiconductor layer. The gate, drain and source electrodes are disposed over the hetero-junction structure. The gate electrode is located between the drain electrode and the source electrode, and an active area of the hetero-junction structure located between the drain electrode and the source electrode is overlapped with the recess of the substrate.

Abstract: An imaging device includes a transducer that includes an array of piezoelectric elements formed on a substrate. Each piezoelectric element includes at least one membrane suspended from the substrate, at least one bottom electrode disposed on the membrane, at least one piezoelectric layer disposed on the bottom electrode, and at least one top electrode disposed on the at least one piezoelectric layer. Adjacent piezoelectric elements are configured to be isolated acoustically from each other. The device is utilized to measure flow or flow along with imaging anatomy.

Abstract: The present invention relates to a display device including a speaker using piezoelectric elements having an amplification effect in a low frequency range.

Abstract: Sound direction detection devices include cylinders or other longitudinally extended structures having rotational symmetry about their longitudinal axes and multiple, rotationally equivalent resonators contained therein. Each resonator contains a microphone or other transducer that is activated when the resonator resonates.

Abstract: A magnetic field sensor element with a piezo electric substrate having predetermined shear wave velocity VS, two pairs of interdigital electrodes, arranged on the substrate on the ends of a delay section, having a period length p of at least 10 micrometers, a non-magnetic, electrically non-conductive guide layer arranged on the substrate along the delay section, and a magnetostrictive functional layer arranged on the guide layer, wherein the shear wave velocity in the guide layer is smaller than VS, wherein a) the substrate is oriented to generate and propagate mechanical shear waves upon applying a temporally periodic, electrical voltage to at least one interdigital electrode pair in the range of frequency VS/p and, wherein b) the thickness of the guide layer equals at least 10% and at most 30% of the period length p of the interdigital electrodes.

Abstract: A micro-speaker, the manufacturing method thereof, a speaker device and an electronic apparatus are described herein. The micro-speaker comprises a case, wherein the case has an opening; and a piezoelectric layer, wherein one or more electrodes are provided on the piezoelectric layer, and wherein the piezoelectric layer is pre-buckled in its rest position, wherein the piezoelectric layer covers the opening and is bonded onto the case, to form a speaker rear cavity together with the case. The micro-speaker of the present invention has a relatively low speaker profile.

Abstract: An acoustic resonator is disclosed. The acoustic resonator comprises a substrate, a first electrode, a second electrode and a piezoelectric layer positioned between the first electrode and the second electrode. An acoustic reflector is positioned between the first electrode and the substrate. An active area comprises a region of contacting overlap of the acoustic reflector, the first electrode, the piezoelectric layer and the second electrode. A gap region extends around the active area.

Abstract: A piezoelectric drive device includes: a vibrating body having a first surface and a second surface provided with a recessed portion; and a piezoelectric element provided on the first surface. The recessed portion and the piezoelectric element have an overlap region when viewed in a normal direction of the second surface.

Abstract: A piezoelectric assembly, a screen component, and a mobile terminal are provided. The piezoelectric assembly can include a vibrating member made of a piezoelectric material and a signal line connected to the vibrating member. The vibrating member includes two or more piezoelectric layers stacked in sequence. A size of at least one of the piezoelectric layers is smaller than a size of any remaining one of the piezoelectric layers to form a stepped structure.

Abstract: Described is a micro-haptic actuator device that can be fabricated with roll-to-roll MEMS processing techniques. The device includes a first body having a first surface and a second, opposing surface, the body has a chamber defined by at least one interior wall, a piston member disposed in the chamber, physically spaced from the at least one interior wall of the chamber, the piston member having a first surface and a second opposing surface. A membrane layer is disposed over and attached to the first surface of the body, with a portion of the membrane attached to the first surface of the piston member. The device also includes a first electrode supported on a second surface the membrane, and a second body that supports a second electrode, with the second body attached to the second surface of the first body.

Abstract: A microphone is provided. The microphone includes a shell with an accommodating cavity, as well as a micro-electro-mechanical system chip and a control circuit chip accommodated in the accommodating cavity, where the shell is provided with a sound hole penetrating through a thickness of the shell and communicated with the accommodating cavity; the microphone further includes an electric anti-dust device at least completely covering the sound hole, the electric anti-dust device is electrically connected with the control circuit chip, and can open the sound hole when receiving a power-on signal of the control circuit chip and close the sound hole when not receiving the power-on signal of the control circuit chip, thus effectively improving a pollution problem of the microphone during such process as transportation, assembly, SMT or unused state that dust is fed most easily without affecting an acoustic performance.

Abstract: Embodiments herein provide a method for producing a binaural audio signal. The method includes detecting at least one audio signal and a current viewport information of a user wearing a Head Mounted Display (HMD) device. Further, the method includes determining a location of origin of the at least one audio signal based on the current viewport information. Further, the method includes determining the binaural audio data individually for each of vibrational transducers arranged on a support structure of the HMD device based on the location of origin of the at least one audio signal. Furthermore, the method includes presenting the binaural audio data the user using the corresponding vibrational transducer/using combined effect of all the vibrational transducers.

Abstract: A film bulk acoustic wave resonator includes a first substrate; a first insulating material layer, formed on the first substrate; a first cavity, formed in the first insulating material layer with an opening facing away from the first substrate; and an acoustic-wave resonant plate, including a first electrode, a piezoelectric oscillation plate, and a second electrode stacked on the first insulating material layer. The piezoelectric oscillation plate is disposed between the first electrode and the first electrode. The first electrode includes a first electrode cavity above the first cavity. The second electrode includes a second cavity above the first cavity. At least a portion of a boundary of the piezoelectric oscillation plate is formed by a boundary of the first electrode cavity and a boundary of the second electrode cavity. The boundary of the piezoelectric oscillation plate has an irregular polygonal shape without having two parallel edges.

Abstract: A panel loudspeaker controller for controlling a panel loudspeaker including a plurality of actuators, the panel loudspeaker controller including a plurality of electrical signal inputs, each input being associated with each actuator of the panel loudspeaker to be controlled; a plurality of signal processors, each signal processor being associated with each input and having an output for an electrical signal to control an actuator of the panel loudspeaker, and each signal processor implementing a transfer function from its input to its output based on each actuator of the panel loudspeaker to a desired acoustic receiver; and a signal processor controller associated with all of the plurality of signal processors, wherein the signal processor controller is preconfigured to improve phase alignment between the signals as an ensemble output at the outputs of the signal processors.

Abstract: An acoustic sensor comprises a side wall closed at each end by an end wall to form a cavity which, in use, contains a fluid. At least one transmitter and at least one receiver are operatively associated with one of the end walls. A maximum half width, a, of the cavity and a height, h, of the cavity satisfies the following inequality: a/h is greater than 1.2. In use, the transmitter causes oscillatory motion of the region of the end wall operatively associated with the transmitter, in a direction substantially perpendicular to the plane of the end walls such that the perpendicular oscillations of the end walls drive substantially in-plane oscillations of the fluid pressure in the cavity. The substantially in-plane oscillations in the pressure of the fluid drive substantially perpendicular oscillatory motion of the region of the end wall operatively associated with the receiver, resulting in an electrical signal from the receiver.

Abstract: A pump comprising a side wall closed at each end by an end wall forming a cavity for, in use, containing a fluid, one or more actuators each operatively associated with one or more of the end walls to cause an oscillatory motion of the associated end wall(s) whereby, in use, these axial oscillations of the end wall(s) drive substantially radial oscillations of the fluid pressure in the cavity, two or more apertures in the cavity, a valve disposed in at least one of the apertures, wherein the actuator(s) is arranged to be non-axisymmetric in use such that, in use, a pressure oscillation with at least one nodal diameter is generated within the cavity.

Abstract: The construction of a medical device having a disposable element is disclosed. Detachable elements comprising a body having a retention feature, an electrical contactor, and sensors are also disclosed. Further disclosed are detachable elements comprising a body having a hole and a retention pocket, an electrical contactor, and a printed circuit board assembly (PCB) in contact with the innermost surface of the body that forms the retention pocket. Further disclosed are detachable elements comprising a body having an opening and a printed film comprising conductive elements, where the conductive elements comprise a sensor configured to be aligned with the opening to expose the sensor. Further disclosed are reusable components having matching retention features.

Abstract: An acoustic transducer is provided. The acoustic transducer includes a housing, a backing, a piezocomposite element adjacent the backing within the housing, and a diaphragm covering on an outward facing surface of the piezocomposite element.

Abstract: Some embodiments include a semiconductor construction having a gate extending into a semiconductor base. Conductively-doped source and drain regions are within the base adjacent the gate. A gate dielectric has a first segment between the source region and the gate, a second segment between the drain region and the gate, and a third segment between the first and second segments. At least a portion of the gate dielectric comprises ferroelectric material. In some embodiments the ferroelectric material is within each of the first, second and third segments. In some embodiments, the ferroelectric material is within the first segment or the third segment. In some embodiments, a transistor has a gate, a source region and a drain region; and has a channel region between the source and drain regions. The transistor has a gate dielectric which contains ferroelectric material between the source region and the gate.

Abstract: A piezoelectric actuator includes a substrate, a first electrode arranged on the substrate, a piezoelectric body stacked on the first electrode, a second electrode superimposed on a surface of the piezoelectric body on a side opposite to the first electrode, and a wiring connected to the first electrode. The first electrode has a connecting portion which is arranged to protrude from an end portion of the piezoelectric body and to which the wiring is connected, and a first conductive portion is provided so that the first conductive portion overlaps with the first electrode while extending over from an area overlapped with the end portion of the piezoelectric body up to the connecting portion of the first electrode.

Abstract: An improved hydrophone is presented that has extremely low acceleration sensitivity, hermetic sealing, and is self-shielded. The hydrophone can also contain an integral amplifier and pressure/depth limiting switch. The hydrophone is also designed such that it can use a single standard piezoelectric sensing element in many hydrophone designs that have different acoustic pressure sensitivities but the same capacitance. Lastly, the sensor is also designed to be low cost in high volumes using standard accelerometer manufacturing techniques. A hydrophone is also designed such that it can use a single standard piezoelectric sensing element that can be incorporated into several hydrophone configurations with varying acoustic pressure sensitivities. The sensor is also designed to be low cost in high volumes.

Abstract: A bulk acoustic wave (BAW) resonator is disclosed. The BAW resonator includes: a lower electrode; a piezoelectric layer disposed over the lower electrode; and an upper electrode over the piezoelectric layer. An opening having a first area exists in and extends completely through the upper electrode. The BAW resonator also includes a substrate disposed below the lower electrode; a cavity; and a pillar disposed in the cavity and extending to contact a portion of the lower electrode disposed beneath the opening. The pillar has a second area that is less than the first area. There are no electrical connections that extend across the opening from one side to another.

Abstract: An ultrasonic device includes a substrate having an opening portion penetrating through the substrate in a thickness direction; a membrane formed on the substrate and having a movable film defining a top surface portion of the opening portion; a lower electrode formed on a front surface of the membrane at a side opposite the opening portion; a piezoelectric film formed on a front surface of the lower electrode at a side opposite the membrane; and an upper electrode formed on a front surface of the piezoelectric film at a side opposite the lower electrode, wherein the movable film of the membrane has a shape that is deflected so as to be convex toward the lower electrode, and wherein the lower electrode is an IrOx/Ir/Ti/Pt laminated film with which an IrOx film, an Ir film, a Ti film, and a Pt film are laminated in that order from the membrane.

Abstract: The present invention relates to an ultrasound transducer device comprising at least one cMUT cell (30) for transmitting and/or receiving ultrasound waves, the cMUT cell (30) comprising a cell membrane (30a) and a cavity (30b) underneath the cell membrane. The device further comprises a substrate (10) having a first side (10a) and a second side (10b), the at least one cMUT cell (30) arranged on the first side (10a) of the substrate (10). The substrate (10) comprises a substrate base layer (12) and a plurality of adjacent trenches (17a) extending into the substrate (10) in a direction orthogonal to the substrate sides (10a, 10b), wherein spacers (12a) are each formed between adjacent trenches (17a). The substrate (10) further comprises a connecting cavity (17b) which connects the trenches (17a) and which extends in a direction parallel to the substrate sides (10a, 10b), the trenches (17a) and the connecting cavity (17b) together forming a substrate cavity (17) in the substrate (10).

Abstract: A device, system and method for harvesting electrical power from hydraulic fluid of a hydraulic system determines at least one of hydraulic fluid flow or hydraulic fluid pressure in the hydraulic system. Based on rules and the determined at least one of the hydraulic fluid flow or hydraulic fluid pressure, an expected conversion efficiency of the power conversion device and an expected rectified power to be generated from the received input power by the power conversion device are determined. From the expected rectified power a potential conversion efficiency of the power conversion device is determined, and the power conversion device is commanded to produce the expected rectified power when the potential conversion efficiency is greater than or equal to the expected conversion efficiency. When the potential conversion efficiency is less than the expected conversion efficiency, the rules are updated.

Abstract: A substrate includes a substrate main body that includes a first main surface and a second main surface facing the first main surface. First electrode lands are disposed inside a recessed portion of the first main surface of the substrate main body. Second electrode lands are disposed in a region outside the recessed portion. The first electrode land and the second electrode land are connected to different electric potentials.

Abstract: Cylindrical ventilation ports radiating sound radiated from a rear surface of a diaphragm to an outside are projected from a rear surface of the electroacoustic converter having the diaphragm inside. A distal end of each ventilation port is located in a through hole of a circuit board, on which the electroacoustic converter is mounted, at a position farther away from the diaphragm than a contact surface of the circuit board. The distal end of each ventilation port may be in the through hole or may be protruded to the outside from the rear surface of the circuit board. As a result, since separation from the radiated sound from the front surface of the diaphragm is achieved, the radiated sound from the rear surface of the diaphragm is prevented from interfering with the radiated sound from the front surface of the diaphragm.

Abstract: A piezoelectric thin film-stacked body is provided. A piezoelectric thin film-stacked body has a first electrode layer, a first oxide layer stacked on the first electrode layer, a second oxide layer stacked on the first oxide layer, and a piezoelectric thin film stacked on the second oxide layer, the electrical resistivity of the first oxide layer is higher than the electrical resistivity of the second oxide layer, the first oxide layer includes K, Na, and Nb, and the piezoelectric thin film includes (K,Na)NbO3.

Abstract: Bulk Acoustic Wave (BAW) resonators that include a modified outside stack portion and methods for fabricating such BAW resonators are provided. One BAW resonator includes a reflector, a bottom electrode, a piezoelectric layer, and a top electrode. An active region is formed where the top electrode overlaps the bottom electrode and an outside region surrounds the active region. The piezoelectric layer includes a top surface adjacent to the top electrode and a bottom surface adjacent to the bottom electrode. The piezoelectric layer further includes an outside piezoelectric portion in the outside region with a bottom surface in the outside region that is an extension of the bottom surface of the piezoelectric layer, and the outside piezoelectric portion includes an angled sidewall that resides in the outside region and extends from the top surface of the piezoelectric layer to the bottom surface of the outside piezoelectric portion in the outside region.

Abstract: An electronic device that includes a housing and a piezoelectric sensor. The piezoelectric sensor is disposed in contact with an inner wall surface of the housing while in a bent state. The piezoelectric sensor includes a piezoelectric film, a coverlay, a first electrode, a second electrode, a third electrode, and a substrate having flexibility. The first electrode is disposed on a surface of the substrate. The first electrode includes a wide part and a narrow part. The coverlay covers a boundary between the wide part and the narrow part. The piezoelectric film covers a boundary between a part of the first electrode which is covered with the coverlay and a part of the first electrode which is not covered with the coverlay.

Abstract: A bulk acoustic wave resonator includes: a substrate; a lower electrode disposed on the substrate; a piezoelectric layer at least partially disposed on the lower electrode; and an upper electrode disposed on the piezoelectric layer, wherein either one or both of the lower electrode and the upper electrode includes a layer of aluminum alloy including scandium (Sc).