125 results about "Piezoelectric mems" patented technology

Systems, devices, methods, and implementations related to contact detection are described herein. In one aspect, a system is provided. The system includes a first piezoelectric microelectromechanical systems (MEMS) transducer coupled to configured to generate a first analog signal when the first analog signal is transduced from vibrations propagating through the object. The system includes a second piezoelectric MEMS transducer having configured to generate a second analog signal transduced from acoustic vibrations at a location of the object, and classification circuitry coupled to the output of first piezoelectric MEMS transducer and the output of the second piezoelectric MEMS transducer, where the classification circuitry is configured to process data from the first analog signal and data from the second analog signal, and to categorize combinations of the first analog signal and the second analog signal received during one or more time frames.

The invention relates to the technical field of semiconductor technology, in particular to a piezoelectric MEMS chip-based PMUT and a preparation method thereof, the piezoelectric MEMS chip-based PMUT comprises a substrate, the substrate is provided with a front surface and a back surface which are opposite to each other, a piezoelectric layer is formed on the front surface of the substrate, the substrate is provided with a back cavity in a penetrating manner, a structural layer is formed on the surface of the piezoelectric layer, and the thickness of the structural layer is greater than that of a piezoelectric film in the piezoelectric layer; the neutral surface is located in the transverse projection area range of the structural layer; an isolation groove is formed in the area, located in the vibrating diaphragm, of the top electrode of the piezoelectric layer, and the isolation groove divides the top electrode into an internal electrode and an external electrode which are independent of each other. The preparation method comprises the following steps: growing the piezoelectric layer on the front surface of the substrate; etching the top electrode; growing a structural layer; and penetrating through the etching substrate to form a back cavity. The silicon oxide is used as the structural layer, the Young modulus of the silicon oxide is low, the process stress is low, the resonant frequency can be effectively reduced, on the basis, the top electrode is etched to form the slit, and stress release is achieved.

A piezoelectric valve comprising: a fixed portion defining an opening; and a number of movable portions extending from the fixed portion over the opening and separated from one another by radially oriented slits, each movable portion of the number of movable portions comprising a first material layer and a second material layer, and at least one of the first material layer or the second material layer comprises a piezoelectric material that is operable to drive a displacement of the movable portion in a direction opposite to an adjacent movable portion sharing a same radially oriented slit upon application of a voltage.

The invention discloses a piezoelectric MEMS transducer and electronic equipment, and relates to the technical field of MEMS. The piezoelectric MEMS transducer comprises a substrate and a piezoelectric layer formed on the substrate, a cavity is further formed in the substrate, a bottom electrode is arranged on the first surface of the piezoelectric layer, and a first differential electrode and a second differential electrode are arranged on the second surface of the piezoelectric layer; the first differential electrodes and the second differential electrodes are alternately distributed on the second surface of the piezoelectric layer in the first direction, and the bottom electrodes are opposite to the first differential electrodes and the second differential electrodes; the piezoelectric layer is a single-crystal lithium niobate film or a single-crystal lithium tantalate film, the first direction serves as the x-axis positive direction of a right-handed coordinate system, the piezoelectric layer has crystal orientation of a target Euler angle, and the square value of the piezoelectric coupling coefficient of the piezoelectric layer in the first direction is larger than or equal to 1.52%. According to the piezoelectric MEMS transducer, the electromechanical coupling coefficient of the piezoelectric MEMS transducer can be improved.

The invention relates to a two-dimensional biaxial piezoelectric MEMS (Micro Electro Mechanical System) micromirror, belongs to the technical field of semiconductor equipment, and solves the problem that the MEMS micromirror in the prior art cannot be overturned at a large angle. The MEMS micromirror comprises a silicon wafer substrate, and a reflecting mirror surface and N cantilever beams which are formed by etching on the silicon wafer substrate, and N is 2 or 4; the N cantilever beams are symmetrically arranged on the periphery of the reflecting mirror surface, the fixed ends of the N cantilever beams are integrally connected with the silicon wafer substrate, and the free ends of the N cantilever beams are integrally connected with the reflecting mirror surface; the fixed ends are uniformly distributed on the silicon wafer substrate, and the free ends are uniformly distributed on the reflecting mirror surface; each cantilever beam is provided with a piezoelectric driving block, after the piezoelectric driving blocks are powered on, the piezoelectric driving blocks drive the cantilever beams to bend, and the bending of the cantilever beams drives the reflection mirror surface to turn over. And the large-angle overturning of the MEMS micro-mirror during working is realized.

A piezoelectric sensor (e.g., for use in a piezoelectric MEMS microphone) includes a substrate and a cantilever beam attached to the substrate. The cantilever beam has a proximal portion attached to the substrate and extending to an unsupported distal end. An electrode is disposed on or in the proximal portion of the beam and has an outer boundary with a shape substantially corresponding to a contour line of a strain distribution plot for the cantilever beam resulting from a force applied to the cantilever beam.

The invention provides a piezoelectric MEMS device and a preparation method thereof, and relates to the technical field of semiconductors. The piezoelectric MEMS device comprises a first vibration layer, an electrode layer and a second vibration layer, the electrode layer and the second vibration layer are arranged on the first vibration layer, the electrode layer is provided with a first electrode surface and a second electrode surface which are opposite in a preset direction, and an electrode side face connected with the first electrode surface and the second electrode surface. The outer contour of the orthographic projection of the electrode side face on the first vibration layer is located in the outer contour of the surface, facing the electrode layer, of the first vibration layer, the first vibration layer completely covers the first electrode surface, and the second vibration layer completely covers the second electrode surface and the electrode side face. According to the piezoelectric MEMS device, the first vibration layer and the second vibration layer are arranged on the two sides of the electrode layer respectively, all the exposed faces of the electrode layer are wrapped by the first vibration layer and the second vibration layer, and all-dimensional anti-corrosion protection of the electrode layer is achieved. Therefore, the piezoelectric MEMS device can prevent the electrode layer from being corroded, and has relatively long service life.

The present invention relates to the fields of ferroelectric single crystal technology and acousto-optical device technology, particularly to a silicon-based lead magnesium niobate (PbMn) single crystal piezoelectric wafer structure, preparation method, and application. The structure comprises a silicon substrate on which a silicon dioxide layer and a single crystal piezoelectric thin film layer are sequentially disposed; the single crystal piezoelectric thin film layer is a PbMn-PT single crystal, including a binary PMN-PT single crystal thin film or a ternary PIN-PMN-PT single crystal thin film. This piezoelectric wafer structure on a silicon substrate can be used to fabricate various high-performance piezoelectric MEMS sensors, actuators, and electro-optical modulator devices. The resulting surface acoustic wave (SAW) filters and thin film bulk acoustic wave (BAW) filters exhibit a relative bandwidth increase of over 50%, and the resulting electro-optical modulators exhibit lower half-wave voltage and higher electro-optical modulation efficiency. The device volume can be reduced by 10 times, better meeting the future 6G communication requirements for higher efficiency, higher integration, and miniaturization of MEMS devices. This provides a novel multilayer piezoelectric wafer structure for the miniaturization and integration of piezoelectric MEMS and optoelectronic devices.

The utility model provides a piezoelectric MEMS accelerometer and a piezoelectric vector hydrophone, and belongs to the technical field of sound wave sensing. The piezoelectric MEMS accelerometer comprises a base body, wherein the middle part of the base body is provided with a cylindrical through area; the mass block is cylindrical and is arranged in the through area, and an annular area is formed between the mass block and the base body; the multiple cantilever beams are evenly arranged in the annular area in the circumferential direction of the mass block, the two ends of each cantilever beam are connected with the mass block and the base body respectively, each cantilever beam comprises a substrate layer, a lower electrode layer, a piezoelectric layer and an upper electrode layer which are sequentially stacked, a through hole used for exposing the lower electrode layer is formed in the piezoelectric layer, and a through hole used for exposing the upper electrode layer is formed in the upper electrode layer. The upper electrode layer comprises an inner electrode and an outer electrode which are arranged at intervals in the radial direction of the mass block, and the inner electrode and the outer electrode are located in opposite cantilever beam deformation areas. The piezoelectric MEMS accelerometer provided by the utility model is adjustable in sensitivity and flexible to use.

The utility model provides a piezoelectric MEMS sounding unit and a loudspeaker, each peripheral area of the upper surface of a substrate is provided with a first piezoelectric composite unit, the middle rectangular area of the substrate is provided with a slotted gap, the edge of each diaphragm of a formed diaphragm structure is anchored, a gap structure is arranged between every two adjacent first piezoelectric composite units, and the first piezoelectric composite units and the second piezoelectric composite units are arranged in the slotted gap. The internal stress of each diaphragm layer in the diaphragm structure of the piezoelectric MEMS sound production unit due to the process can be reduced by arranging the slotting gap; the flexible material is adopted to cover the slotting gap, the flexibility of the vibrating diaphragm structure can be improved, meanwhile, sound leakage of the piezoelectric MEMS sound production unit at low frequency is reduced, the vibration amplitude and the emission sound pressure level are improved, the flexible material with low density is adopted to replace a silicon vibrating diaphragm with high density, the quality of the vibrating diaphragm structure is reduced, and the cost is reduced. The flexible material reduces the quality factor Q of the resonance of the device, and is beneficial to improving a sound pressure level SPL frequency response curve and a THD frequency response curve, thereby improving the tone quality of the piezoelectric MEMS sound production unit.

A piezoelectric microelectromechanical systems device can include a cavity bounded by walls and an asymmetrical bimorph structure at least partially spanning the cavity that includes at least a piezoelectric layer and two electrode layers. The electrode layers can have relative thicknesses configured to compensate for expected temperature stress in the bimorph structure. Thus, metals having different thicknesses can be positioned and configured to compensate deflection due to thermal stress of any or all of the piezoelectric layer, the first metal layer, and second metal layer and a substrate. A method for making the piezoelectric microelectromechanical systems device is also provided.

The invention discloses a fixed end beam-cantilever beam type piezoelectric MEMS loudspeaker and a preparation method and application thereof. The piezoelectric MEMS loudspeaker comprises a substrate, an upper electrode, a piezoelectric layer, a lower electrode and a vibrating membrane, the upper electrode, the piezoelectric layer and the lower electrode are sequentially arranged on the substrate, and the vibrating membrane and an etching gap surrounding the vibrating membrane are formed on the upper electrode, the piezoelectric layer and the lower electrode in an etching mode; the vibration displacement of the fixed end beam-cantilever beam type piezoelectric MEMS loudspeaker is very large, and is mainly attributed to the superposition of the vibration displacement of the fixed end beam and the vibration displacement of the cantilever beam.

The invention provides a piezoelectric MEMS transducer and an electrical product. The piezoelectric MEMS transducer comprises a first electrode layer, a second electrode layer and a single crystal piezoelectric film, the first electrode layer and the second electrode layer are correspondingly attached to the surfaces of the two sides of the single crystal piezoelectric film respectively. The single-crystal piezoelectric film is a single-crystal lithium niobate film or a single-crystal lithium tantalate film, and the single-crystal piezoelectric film has a determined cutting type of a target Euler angle, so that the piezoelectric coupling coefficient of the single-crystal piezoelectric film is not less than 6.4% or the absolute value of an e33 coefficient in a piezoelectric constant matrix is not less than 1.55; wherein the piezoelectric MEMS transducer works in a thickness expansion and contraction mode.

The invention provides a piezoelectric structure, a piezoelectric MEMS microphone and a preparation method of the piezoelectric structure, and relates to the technical field of semiconductors. The piezoelectric structure comprises a first electrode layer and at least one composite film layer arranged on the first electrode layer in the first direction, each composite film layer comprises a piezoelectric layer and a second electrode layer arranged on the side, away from the first electrode layer, of the piezoelectric layer, and a narrow gap is formed in the surface of the second electrode layer farthest from the first electrode layer; the narrow gap penetrates through two opposite surfaces of the piezoelectric structure in the first direction so as to divide the piezoelectric structure into at least two cantilever beams; the first electrode layer is provided with a first gap, the narrow gap is located in the first gap, and the outline of the narrow gap does not intersect with the outline of the first gap. According to the piezoelectric structure, the first gap corresponding to the position of the narrow gap is formed in the first electrode layer, and during slotting, etching gas cannot directly react with the first electrode layer to generate a metal polymer, so that the etching rate can be prevented from being slowed down, and the probability of slotting failure is reduced.

The invention relates to the field of semiconductor devices and provides a piezoelectric MEMS resonator and an electronic component. The resonator comprises a cap wafer and a device wafer, the cap wafer comprises a cap layer, and the device wafer comprises a substrate layer; the resonance cavity is arranged on the substrate layer; the device silicon layer is positioned on the upper side of the resonant cavity; the piezoelectric layer is positioned on the upper side of the device silicon layer; the top electrode is positioned on the upper side of the piezoelectric layer; the first dielectric layer is located on the upper side of the top electrode and covers the top electrode, the first dielectric layer is in bonding connection with the cap layer, and the projection of at least one part, bonded with the cap layer, of the first dielectric layer in the vertical direction is overlapped with the projection of the top electrode in the vertical direction; and at least the upper surface of the part, bonded with the cap layer, of the first dielectric layer is in the same plane. Therefore, the bonding characteristics of the cap wafer and the device wafer are improved by flattening the surface of the dielectric layer covering the top electrode, and a good bonding effect is ensured.

The invention provides a packaging structure for a piezoelectric MEMS resonator and an electronic component, and belongs to the field of semiconductor devices.The packaging structure comprises a device wafer, a cap wafer, a first insulating layer and a metal layer, and the first insulating layer and the metal layer are arranged on the cap wafer. The substrate layer comprises a substrate area and a first resonance cavity area surrounded by the substrate area; the device silicon layer, the first dielectric layer, the piezoelectric layer and the top electrode layer are arranged on the substrate layer; the cap wafer comprises a cap layer; the first annular isolation groove is formed in the cap layer, and the first annular isolation groove is filled with a second dielectric layer; wherein the surface, bonded with the cap wafer, of the device wafer is the surface, far away from the substrate layer, of the device silicon layer, the surface, bonded with the device wafer, of the cap wafer is the surface, far away from the first insulating layer, of the cap layer, and the cap layer is made of low-resistance monocrystalline silicon. According to the packaging structure, the packaging vacuum degree can be effectively improved, and the working performance of the resonator is improved.

The invention provides a piezoelectric MEMS accelerometer and a preparation method thereof. Two ends of a cantilever structure of the piezoelectric MEMS accelerometer are respectively provided with a first piezoelectric sensitive structure and a second piezoelectric sensitive structure. When the piezoelectric MEMS accelerometer is subjected to forward acceleration, the first piezoelectric sensitive structure deforms forward, and the first upper electrode and the first lower electrode generate inductive charges + Q1 and-Q1 respectively; the second piezoelectric sensitive structure deforms reversely, and the second upper electrode and the second lower electrode generate inductive charges-Q2 and + Q2 respectively; the first upper electrode of the first piezoelectric sensitive structure is connected with the second lower electrode of the second piezoelectric sensitive structure, and the first lower electrode of the first piezoelectric sensitive structure is connected with the second upper electrode of the second piezoelectric sensitive structure, so that the overall inductive charges of the first piezoelectric sensitive structure and the second piezoelectric sensitive structure are + (Q1 + Q2) and-(Q1 + Q2); inductive charges are greatly increased, and sensitivity is improved.

The invention discloses a piezoelectric MEMS loudspeaker based on a folding ring between movable and fixed parts and application thereof, and belongs to the technical field of loudspeakers, the piezoelectric MEMS loudspeaker comprises a piezoelectric actuating assembly, a fixed assembly and a folding ring; the piezoelectric actuating assembly comprises a piezoelectric actuating composite layer, the piezoelectric actuating composite layer at least comprises a piezoelectric material layer, and the piezoelectric actuating composite layer generates mechanical displacement by applying voltage to drive the piezoelectric actuating assembly to vibrate so as to generate sound pressure; the fixing component can be a single structural component or a component with a plurality of structural components; the fixing assembly can be used for fixedly supporting the fixed supporting part of the piezoelectric actuating assembly, so that the non-fixed supporting part of the piezoelectric actuating assembly can freely move or vibrate; according to the invention, through the innovative design based on the folding ring between the moving part and the fixed part, the low-frequency vibration displacement of the vibrating diaphragm is remarkably improved, the problem that the low-frequency sound pressure of a traditional piezoelectric MEMS loudspeaker is insufficient is effectively solved, and the vibrating diaphragm can push air with a larger volume in a low-frequency band, so that a fuller low-frequency sound effect is obtained.

The present invention specifically relates to a method for preparing a piezoelectric MEMS smart speaker, including: using a theoretical formula for film vibration frequency to preliminarily calculate the film vibration frequency according to a target frequency range; using finite element analysis software to perform simulation and predict the resonance frequency of each vibration membrane to determine the material of each layer; selecting a piezoelectric material; selecting a substrate material; sputtering a first electrode material on the substrate, and etching to form a required electrode pattern; depositing a piezoelectric layer material to ensure uniform thickness; sputtering a second electrode material on the piezoelectric layer, and etching to form a required electrode pattern; testing the actual performance frequency of the speaker; adjusting the thickness or shape of the piezoelectric layer according to the test results; and also including using a dynamic algorithm to adjust the thickness or shape of the piezoelectric layer; re-depositing the piezoelectric layer and adjusting it; until the resonance frequencies of all vibration membranes are within the target range.

This application relates to the field of acoustic transducers, and particularly to a high-sensitivity MEMS acoustic device and its fabrication method. The high-sensitivity MEMS acoustic device is composed of an upper electrode layer, a piezoelectric layer, a lower electrode layer, a passive layer, an insulating layer, and a substrate connected in sequence. The multilayer composite film is radially symmetrical on the passive layer. A slit through the center of radial symmetry divides the composite film into several partitions. The upper and lower electrode layers of each partition are respectively provided with pads for signal extraction. The voltage signals of the pads in each partition are extracted through series or parallel connection. This application increases the output voltage by dividing the piezoelectric sensitive composite film into multiple sensitive regions and combining the sensitive regions in series, antiphase superposition, or other forms, thereby improving the sensitivity of the piezoelectric MEMS device.

A piezoelectric microelectromechanical systems microphone is provided comprising a substrate including at least one wall defining a cavity, the at least one wall defining an anchor region around a perimeter, a piezoelectric film layer forming a membrane, the piezoelectric film layer being supported at the anchor region by a spring region, and an electrode disposed over the piezoelectric film layer. A method of manufacturing such a MEMS microphone is also provided.

There is provided a piezoelectric microelectromechanical systems microphone comprising a sensor including at least one piezoelectric layer, at least one constraint in contact with the sensor at a position, such that the sensor is supported by the at least one constraint, and such that the sensor that the sensor has a membrane region to one side of the at least one constraint and a cantilevered region to the other side of the at least one constraint and a cavity defined at least partially by the at least one constraint. There is also provided a method of manufacturing the microphone.

A piezoelectric MEMS loudspeaker. The application discloses a MEMS structure, comprising: a substrate comprising an inner ring body and an outer ring body connected by a connecting rod, having a first cavity between the inner ring body and the outer ring body, and having a second cavity in the inner ring body; a piezoelectric composite vibration layer formed above the substrate, comprising an edge portion formed above the outer ring body and a center portion formed above the inner ring body, having a partition gap between the edge portion and the center portion. In summary, the piezoelectric MEMS loudspeaker provided by the application comprises an edge portion and a center portion, wherein the edge portion is used to generate a high-frequency sound pressure level, and the center portion is used to generate a low-frequency sound pressure level. The combination of the edge portion and the center portion makes the piezoelectric MEMS loudspeaker have a relatively flat sound pressure level frequency response curve with a wider range, thereby improving the auditory effect in the entire frequency band.

The application discloses a piezoelectric MEMS device preparation process and a device structure, and relates to the technical field of piezoelectric MEMS device preparation. The preparation process comprises the following steps: forming a groove near an edge region on a front surface of a substrate, depositing a sacrifice layer on the front surface of the substrate and patterning the sacrifice layer, so that the sacrifice layer is separated into a center region and an edge support region, forming a piezoelectric-buffer stack on the sacrifice layer and patterning the piezoelectric-buffer stack, and opening a release hole, the release hole being communicated with the center region of the sacrifice layer, introducing etching medium into the release hole to remove the center region of the sacrifice layer, and then etching a back cavity on the back surface of the substrate. The application limits the size of a diaphragm region through the groove, etches the back cavity of the substrate after the sacrifice layer is released, and compared with a traditional method of defining the diaphragm by etching the back cavity, the application completely avoids the size error of the diaphragm caused by the angle deviation of deep silicon etching, accurately locks the profile of the diaphragm, and greatly improves the size consistency and performance stability of devices in the same batch.

The application discloses a piezoelectric MEMS loudspeaker and a performance improvement method thereof, and belongs to the field of MEMS loudspeakers. The application first proposes a cantilever beam structure with a fixed support end perforation, and the structure can change the resonant frequency of the device. Further, based on the structure, the piezoelectric MEMS loudspeaker proposed in the application is composed of a plurality of triangular cantilever beams with different fixed support end perforations. Since the displacement of the triangular cantilever beam at the resonant frequency will be phase-inverted, the driving voltages of various triangular cantilever beams at both sides of the respective resonant frequencies should be opposite. Through the optimization design of the cantilever beam structure, compared with the traditional piezoelectric MEMS loudspeaker, the application can improve the sound pressure level output at the design frequency band without additional process difficulty, make the sound pressure level spectrum curve in the human ear hearing threshold frequency band relatively flat, realize compact layout, and has a good application prospect.

An acoustic sensor (e.g., for use in a piezoelectric MEMS microphone) includes a substrate and a cantilever beam attached to the substrate. The cantilever beam has a proximal portion attached to the substrate and extends to a distal tip at a free end thereof. The cantilevered beam has a multilayer structure with a plurality of piezoelectric layers and a plurality of metal electrode layers, at least a portion of one of the piezoelectric layers interposed between two metal electrode layers. One or more direct current voltage sources are electrically connected to one or more of the plurality of metal electrode layers and configured to apply a direct current bias voltage between at least two of the plurality of metal electrode layers to deflect the cantilever beam to at least partially counteract a deflection of the cantilever beam due to a residual stress in the cantilever beam.

The invention provides a piezoelectric MEMS (Micro Electro Mechanical System) loudspeaker and a preparation method thereof. The piezoelectric type MEMS loudspeaker comprises a substrate supporting layer, a piezoelectric layer and a piezoelectric layer, the multi-cantilever piezoelectric diaphragm array is arranged above the substrate supporting layer, and one side of the edge of the multi-cantilever piezoelectric diaphragm array is fixedly connected with the substrate supporting layer; and the plurality of reinforcing ribs are arranged below the multi-cantilever piezoelectric diaphragm array, are formed by etching SOI wafer substrate silicon and an SOI wafer buried oxide layer, and form an integrated structure with the multi-cantilever piezoelectric diaphragm array to improve the sound pressure level frequency response characteristic of the multi-cantilever diaphragm piezoelectric MEMS loudspeaker. Compared with a piezoelectric MEMS loudspeaker without a reinforcing rib design, the reinforcing rib design suppresses the partial distortion mode of the multi-cantilever piezoelectric diaphragm array, and adjusts the resonance working frequency points of the cantilever piezoelectric diaphragms, so that under the condition of high sound pressure level output, the resonance peak of a high frequency band in a sound pressure level frequency response curve can be obviously reduced, and the sound pressure level output efficiency is improved. The flattening of the medium-high frequency band sound pressure level frequency response curve is realized, so that the effects of reducing distortion and improving sound quality are achieved.

The present application discloses a MEMS structure, comprising a back plate and a piezoelectric composite vibration layer separated by a cavity, wherein the back plate and the piezoelectric composite vibration layer form a capacitive structure, wherein the piezoelectric composite vibration layer comprises a vibration support layer, a first electrode layer, a piezoelectric layer, and a second electrode layer stacked in sequence. The MEMS structure combines the features of a piezoelectric MEMS microphone and a capacitive MEMS microphone, and under the condition of receiving equal sound energy, the MEMS structure obtains more converted electrical energy, thereby increasing the output electrical energy and obtaining a higher sensitivity.

Systems and techniques are provided for fabrication of piezoelectric MEMS devices to improve performance. For example, an apparatus can include a support stack including a substrate and a modified piezoelectric layer formed on or above the support stack. The modified piezoelectric layer includes a material structure modified by non-equilibrium thermal process to increase an average grain size within the material structure of the modified piezoelectric layer. In some implementations, the modified piezoelectric layer includes an aluminum nitride (AlN) crystalline lattice where at least a portion of aluminum in the AlN crystalline lattice are replaced with scandium forming aluminum scandium nitride (AlScN).

An acoustic sensor (e.g., for use in a piezoelectric MEMS microphone) includes a substrate and a cantilever beam attached to the substrate. The cantilever beam has a proximal portion attached to the substrate and extending to a distal tip at a free end of the beam. The cantilevered beam has a width in plan view that is greater at a location distal of the proximal portion than at the proximal portion attached to the substrate. One or more electrodes are disposed on or in the proximal portion of the beam.