This letter presents the first piezoelectric micromachined ultrasonic transducer (PMUT) based on thin-film lithium niobate (LiNbO 3 ). The figures of merit (FoMs) of LiNbO 3 as ultrasound sensors and transducers are first studied, showing great prospective as a balanced transceiver platform. Efficient flexural mode excitation is achieved using a proposed lateral-field-excitation (LFE) structure. The

This letter presents an effective approach to mitigating the prolonged issue of the insufficient etching selectivity between the sacrificial oxide and structural metal Al during the final release step of the CMOS-MEMS metal resonators. Particularly, the approach purposely slows down the etching rate not only for the sacrificial oxide but also more effectively for the structural metal by covering the

This letter presents experimental results showing significant enhancement in the dynamic performance of a novel piezoelectric micro-lens actuator using a robust feedback resonant controller. The design of the feedback controller is based on experimentally identified model of the micro-lens actuator. The stability of the closed-loop system is proven by the negative imaginary theory. The experimental

An accurate analytic model of a parametrically driven resonant MEMS mirror is proposed using a Fourier series based approximation for out-of-plane comb drive torque. The analytic model consists of slow evolution equations of the amplitude and phase derived by the averaging theorem of perturbation theory. Based on the model, analytic expressions of the primary frequencies and Jacobian are derived, which

Numerical modelling of MicroElectroMechanical Systems (MEMS) resonators is still attracting increasing interest from the sensors community especially when the nonlinear regime is activated. Here, the dynamic response of two different types of double-ended tuning fork MEMS resonators is studied both in the linear and nonlinear regimes. A one Degree Of Freedom (1 dof) model able to predict the frequency

This paper investigates the impact of resonant frequency ( $f_{\mathrm {s}}$ ) mismatch on the quality factor ( $Q_{\mathrm {as}}$ ) of large arrays of X-cut Lithium Niobate (LN) Laterally Vibrating Resonators (LVRs) operating around 50 MHz and 400 MHz. The statistical distributions of key device parameters, including resonant frequency, quality factor ( $Q_{\mathrm {s}}$ ), electromechanical coupling

This article reports Lithium Niobate (LN) based shear horizontal (SH0) resonators utilizing suspended and solidly mounted structures for radio frequency (RF) applications. The solidly mounted SH0 structure (also termed guided SH0 structure) is advantageous in obtaining reduced temperature coefficient of frequency (TCF), reduced high frequency overtone spurious responses, and improved power handling

Hexagonal 4H-silicon carbide (4H-SiC) is a transversely isotropic substrate garnering interest for precision MEMS devices such as resonant gyroscopes. This paper investigates the elastic anisotropy of 4H-SiC by utilizing capacitive bulk acoustic wave (BAW) resonators with ultra-high mechanical quality factors ( $Q$ ) enabled by phononic crystals. We directly measure the value of $C_{66}$ using Lamé

Based on a bistable mechanism, a novel low- ${g}$ MEMS inertial switch with dual functions of self-locking and reverse-unlocking is presented, along with its fabrication and verification. This MEMS switch is fabricated on a Silicon-On-Insulator (SOI) wafer by using deep reactive ion etching (DRIE), Bosch processing, and wafer bonding technologies. A two-level system is proposed to realize dual functions

Zinc oxide (ZnO) is a metal oxide semiconductor of interest for a wide range of electronic and optoelectronic device applications. Many devices require etching of ZnO structures and there have been many investigations of ZnO wet-etching processes. However, most reported etches have problems with reproducibility and especially control of vertical and lateral (or undercut) etching uniformity. In this

This paper presents a mechanically-robust high-power-density electromagnetic vibration energy harvester fabricated from MP35N alloy. Its primary focus is on the use of MP35N alloy, and the corresponding performance. It follows our prior work on a similar harvester fabricated in silicon that now provides a performance baseline. The optimized design flow developed in our prior work is applied here, yielding

MEMS-enabled multilayer composites, in which microfabrication is used to create micron-scale thickness layers within the volume of meso-scale thickness structures, can be exploited to create materials with highly anisotropic electromagnetic properties. Such materials have utility in both sensing and energy applications, including electrostatic and magnetic energy storage and conversion. A fabrication

Ultraviolet (UV) assisted printing has emerged as a promising additive manufacturing (AM) technology, which puts UV light sources with focused emission in high demand. Unfortunately, current ultraviolet light-emitting diodes (UV LEDs) are not able to provide adequately focused UV emission required for printing. Thus, a UV LED package with focused UV emission was proposed and fabricated using microelectromechanical

Body-biased micro-electro-mechanical (MEM) relays previously have been demonstrated to be a promising alternative to transistors for ultra-low voltage digital logic applications. A basic requirement for reliable relay-based circuit operation is suitably low and stable relay ON-state resistance ( $R_{\mathbf {ON}}$ ). In this work, the effect of body biasing on $\text{R}_{\mathbf {ON}}$ is investigated

A $2\times 2$ high-intensity CMUT transmit array that is capable of two-dimensional beam steering is presented. The device uses an ac drive voltage at half the ultrasound frequency without any dc bias, enabling the usage of the entire gap height. The device is designed using a large signal equivalent model approach. A fabrication method that requires a single lithographic mask has been used. The fabricated

Standard physical vapor deposition systems are large, expensive, and slow. As part of an on-going effort to build a fab-on-a-chip, we have developed a chip-scale, low cost, fast physical vapor deposition system designed to be used with atomic calligraphy or dynamic stencil lithography to direct write nanostructures. The system comprises two MEMS devices: a chip-scale thermal evaporator and a mass sensor

An absolute MEMS capacitance vacuum sensor with a full range of (1-1000) Pa has been designed, fabricated and tested. The working principle of the capacitance vacuum sensor is explained and its fabrication process is introduced. For obtaining high sensitivity, the sensor’s pressure-sensing diaphragm with large width-to-thickness ratio is manufactured using the silicon-on-insulator (SOI). A silicon

Beam electrothermal actuators amplify the thermal expansion of pre-shaped beams and use the symmetrical structure to create a linear motion. These actuators, including V and Z shapes, are widely used in microsystems. Explicit analytical expressions are derived in this paper governing the structural deformation of these actuators due to electrothermal expansion and interaction with external lateral

Electrical impedance measurement of a live cell is important for monitoring the cell’s status. Label-free and non-invasive techniques for measuring the impedance of live cells have attracted much attention. Existing techniques are capable of measuring the impedance of entire cell populations and/or the instantaneous impedance of single cells, but an approach to track and monitor the electrical properties

In the above article [1] , Reference [1] should have read as follows:

The 20th in the series of Solid-State Sensors, Actuators, and Microsystems Hilton Head Workshops was scheduled for May 31–June 4, 2020, at the Sonesta Resort on Hilton Head Island, SC, USA. Unfortunately, like most academic conferences in 2020, it was canceled due to the COVID-19 pandemic. The Hilton Head 2020 Workshop ( https://www.hh2020.org/ ) was designed to continue to represent the science and

A paraffin-based frequency reconfigurable antenna operating at 100 GHz is reported in this article. Paraffin is a mechanical phase-change material (PCM) that undergoes reversible solid-liquid volumetric change of approximately 15%. In addition, due to its low dielectric loss, this material is suitable for certain electromagnetic applications such as antennas at the millimeter-wave band often defined

This article presents GaN two-dimensional electron gas (2DEG) Hall plates with low residual offset and noise at 3 V input bias. We studied devices made from three consecutive fabrication generations through current spinning offset measurements in a zero-field chamber. When operated above 1 V, the first-generation devices charted high residual offsets >1 mT. We reduced these residual offsets by three

This manuscript presents a novel microcantilever with an embedded piezoelectric sensor-actuator pair for dynamic atomic force microscopy (AFM). The transducer pair is constructed from a two-layered AlN stack. Stacking the piezoelectric transducers in this manner leads to a minimal feedthrough from actuation to sense electrode, granting a high dynamic range frequency response for dynamic mode AFM. The

We study thermal-piezoresistive cooling in silicon micromechanical resonators at large currents and high temperatures. Crossing a thermal transition region corresponds to a steep reduction in resonance frequency, an abrupt plateauing in the effective quality factor, and a large increase in thermomechanical fluctuations. Comparing measurements with simulations suggests that the second-order temperature

This work reports on the first demonstration of the frequency tuning and intrinsic polarization switching of film bulk acoustic resonators (FBARs), based on sputtered AlScN piezoelectric thin films with Sc/(Al + Sc) ratio of approx. 30%. A box-like ferroelectric hysteresis behavior of 900 nm-thick Al 0.7 Sc 0.3 N sputtered films is obtained, showing a coercive electric field at ~3 MV/cm. The fundamental

Silicon nanoporous membranes provide the fundamental underlying technology for the development of an implantable bio-artificial kidney. These membranes, which are comprised of micromachined slit-pores that are nominally 10 nm wide, allow for high-efficiency blood filtration as well as immunoprotection for encapsulated cells. Our approach takes advantage of well-established semiconductor fabrication

We report on a non-destructive, on-chip technique for determining the elastic modulus ( $E_{\mathrm {Y}}$ ) of silicon carbide (SiC) thin diaphragms by measuring their nonlinear resonances. Departing from the conventional static load-deflection techniques ( e.g. , beam bending, membrane bulging and nanoindentation), the nonlinear resonance approach enables characterizing mechanical properties without

This work demonstrates two strategies to reduce the energy required for actuation of thin film NiTi unimorph actuators with 3D printed polymeric passive layers. First, by taking advantage of 3D printing, a low mass and high stiffness passive layer can be used to achieve faster heating/cooling rates. This ultimately reduces the time and energy required to achieve a threshold temperature. The second

In this paper, the near-carrier enhancement of phase-noise (PN) at turnover temperature ( ${T} _{to}$ ) in a quasi-thickness-Lamé (QTL) mode thin-film piezoelectric-on-silicon (TPoS) oscillator is reported for the first time. QTL-TPoS resonators fabricated on degenerately-doped n-type silicon offer a ${T} _{to}$ greater than 80°C and are suitable for implementation of highly-stable ovenized oscillators

We present a system for centimeter-precision 3 dimensional localization of a $2\times 3\times 0.3$ mm 3 , 5 mg, wireless system-on-chip by utilizing a temporally-structured infrared illumination scheme generated by a set of base stations. This 3D localization system builds on previous work by adding a second lighthouse station to enable 3D localization and using the integrated wireless radio, making

Crookes radiometers have been the subject of numerous theoretical, numerical, and experimental studies because of the complicated forces they exhibit as well as their potential applications to light sensing and actuation. The majority of these studies have focused on classical radiometers, which function under low vacuum pressures. In contrast, here we report a radiometer with microengineered vanes

This paper presents the design, fabrication, and characterization results of a paper-based, low-cost, easy-to-use, comfortable and wearable tactile sensor array for human health monitoring applications. Paper substrate and spray-deposited metallic electrodes and traces are employed to achieve a low fabrication cost. Capacitive sensing scheme employing a deformable triangular PDMS sensing membrane is

The present work reports on the novel implementation of a miniaturized receiver for underwater networking merging a Piezoelectric Micromachined Ultrasonic Transducer (PMUT) array and signal conditioning circuitry in a single, packaged device. Tests in both a large water tank and a pool demonstrated that the system can attain large enough Signal-to-Noise Ratio (SNR) for communication at distances beyond

This article presents active noise cancelation (ANC) based on MEMS resonant microphone array (RMA) which offers very high sensitivities (and thus very low noise floors) near resonance frequencies and also provides filtering in acoustic domain. The ANC is targeted to actively cancel out any sound between 5–9 kHz (above the speech range of 300 – 3,400 Hz). The ANC works best around the resonance frequencies

Electrochemical techniques such as impedance spectroscopy offer a non-invasive approach to monitor microorganisms in natural and engineered environments. Here, we present data on the use of microfabricated impedance spectroscopy sensors for the detection of microbes in icy environments. Under controlled laboratory settings, the effects of different cell concentrations of the Antarctic isolate Flavobacterium

We present a Lamé mode resonator whose limiting damping mechanism depends on its anchor geometry. The device is anchor-limited when the anchors are stiffer and is Akhiezer-limited with more compliant anchors. This result is determined by observing the temperature dependence of the quality factor (Q) for devices with different lateral dimensions and different anchor designs. The total measured Q increases

Shape memory alloy (SMA) actuators can provide significant advantages for small-scale robotics given their robustness, energy density, and low voltage actuation. However, NiTi thin films typically found in SMA microactuators do not often provide useful forces and displacements for microrobotic applications. This work presents a fabrication process in which NiTi thin film actuators are integrated with

This paper presents a 1-port thickness-shear (TS) mode quartz resonator with very high voltage gain, suitable for use in “near-zero-power” radios. These devices offer voltage gains >100x (referenced to $50~\Omega $ ) at ~50 MHz and >300x at ~75 MHz with ~60 fF load, which is the highest voltage gain directly measured to date in a piezoelectric micromechanical resonator. Six resonators with resonance

We present a wafer-scale fabricated, PDMS-based platform for culturing miniaturized engineered heart tissues (EHTs) which allows highly accurate measurements of the contractile properties of these tissues. The design of the platform is an anisometrically downscaled version of the Heart-Dyno system, consisting of two elastic micropillars inside an elliptic microwell with volume ranging from 3 down to

This article presents a cardiac troponin T (cTnT) sensing electrode fabricated using a molecular imprinted polymer (MIP) for clinical studies for the first time. The MIP-based sensing electrode is an electrochemically polymerized o-phenylenediamine film, which can detect cTnT concentrations ranging from 0.017 to 10 ng/mL in 15 min and can be reused more than six times without any performance degradation

We report the implementation of a passive temperature compensation technique in thermally actuated, silicon-based, resonant cantilever gas sensors vibrating in their fundamental in-plane resonant mode. The temperature compensation technique utilizes oxide-filled trenches along the edges of the cantilever structure and adds a single additional mask to the overall fabrication process. The trench width

Leukocytes are blood cells involved in the immune response. Leukocytes can be classified into three main groups (granulocytes, lymphocytes, and monocytes), and the measurement of the relative prevalence of each subgroup, termed differential leukocyte count, is an important clinical parameter in the diagnosis and prognosis of various health anomalies. Currently, differential leukocyte counts are obtained

Locomoting microscale robots—microswimmers—have the potential to impact numerous applications due to their ability to selectively interact with their environment with microscale control. Previous microswimmer designs lack either submicron-level precision over their construction or instantaneous control over their shape. Thus, existing microswimmer designs limit the control afforded over microswimmer

An approach for gas flow velocity measurement at two different closely located points using a simple device incorporating only one thermal sensing element, is introduced and the feasibility to determine different velocities is experimentally demonstrated. An electrostatically actuated initially curved bistable microbeam heated by an electric current and convectively cooled by airflow is switched between

Printed sensors that rely on low-cost substrate materials and additive fabrication processes are needed for wearable and disposable device applications. A critical challenge associated with currently available printed sensors is their inferior performance compared with sensors fabricated by thin-film deposition or nanoscale assembly. In this paper, we report on an inkjet-printed hydrogen peroxide (H

In this paper, we present the design, fabrication, and characterization of a compact $4\times 4$ piezoelectric micromachined ultrasonic transducer (pMUT) array and its application to photoacoustic imaging. The uniqueness of this pMUT array is the integration of a $4~\mu \text{m}$ -thick ceramic PZT, having significantly higher piezoelectric coefficient and lower stress than sol-gel or sputtered PZT

We report a biodegradable, self-powered sensor for measurement of dissolved oxygen in the body. The principle of operation is the competition of an oxygen reduction reaction against the ordinarily dominant hydrogen reduction reaction at the cathode of a corroding electrochemical couple. Because the relative contribution of the oxygen reduction reaction to the overall electrochemical reaction depends

This paper reports the development of piezoelectrically actuated radio frequency (RF) micro-electromechanical systems (MEMS) switches on Si-on-sapphire substrates using a novel greyscale lithography fabrication technique. Lead zirconium titanate (PZT) thin-film actuators are used to close a series ohmic contact single-pole single-throw (SPST) switch implemented in co-planar waveguide (CPW). The switch

The advent of interconnected devices, sensors, and systems requires increasingly large data transmission rates. Optical communications has met these bandwidth needs due to the large information-carrying capacity of light, although new modulation and multiplexing approaches are required to keep up with increasing demand. To this end, mode-division multiplexing (MDM), in which light propagates in on-chip

Wearable sweat analysis possesses significant potential for transforming personalized and precision medicine, by capturing the longitudinal profiles of a broad spectrum of biomarker molecules that are informative of our body’s dynamic chemistry. However, the lack of established physiological criteria to provide personalized feedback, based on sweat biomarker readings, has prevented the translation

In this work, preliminary investigations into the different sources of sensitivity enhancement of Interdigitated Electrodes (IDEs) on polymer substrates utilized in cell-based biosensing are evaluated. In studying underlying modalities involved in this IDE sensitivity enhancement, we have found that this phenomenon has several components – geometric (electrode gap width), nanostructuring of the substrate

The integration of electrochemical sensors in wearable consumer electronics enables monitoring the health status of individuals at molecular levels across the general population, and thus can play a critical role in transforming personalized and precision medicine. Previously, we devised a seamless integration strategy to interface disposable mediator-free enzymatic sensors—constructed on anisotropic

In this work, we investigate magneto-acoustic attenuation in thin film multiferroic Lamb wave delay lines. By leveraging magneto-acoustic interactions, multiferroics have potential to realize passive chip-scale alternatives to bulky ferrite devices. For the first time, magnetic field dependence of magneto-acoustic interactions in multiferroic Lamb wave devices is characterized. Multiferroic heterostructures

Many micro-aerial vehicles can benefit from having compact and robust pre-deployment configurations that can later transform into larger and more capable forms. We demonstrate parylene-covered silicon frames that can be folded into origami-inspired aerodynamic shapes for structural applications in centimeter-scale aircraft. By changing the spacing between the frames, we can control the conformality

In this paper, we demonstrate a dual frequency oven-controlled MEMS resonator that can be designed to have an output frequency of 1.27 Mhz or 13 Mhz depending on the crystal orientation of the device. Both modes operate based on closed-loop thermal compensation that can offer PPB (parts-per-billion) level temperature stability over a wide temperature range using low power and exhibit strong shock robustness

This work presents successful implementation and characterization of an 8-bit digitally operated micromachined accelerometer. Such device is comprised of an electrostatically tunable acceleration switch with 8 sets of electrostatic tuning electrodes. Similar to bits in a binary number, the tuning force of each electrode set increases by a factor of 2 with respect to the adjacent electrode set. A fabricated

An overview of microelectromechanical systems (MEMS) resonators for frequency reference and timing applications is presented. The progress made in the past few decades in design, modeling, fabrication and packaging of MEMS resonators is summarized. In particular, the state-of-the-art technologies for improving the overall performance of MEMS resonators, such as quality factor ( $Q$ ), motional impedance

This study reports on the development of vertical, partially encapsulated nanoelectrodes for electrically contacting the interior of electrogenic cells with microelectronics. Intracellular electrical stimulation and recording with single cell resolution enables new insights into the electrophysiology of cells embedded in a complex multicellular network, providing detailed understanding of fundamental

CMOS compatibility and 8-inch manufacturability have been highly desired in MEMS technology. In this article, we demonstrate a MEMS pyroelectric IR detector using CMOS compatible AlN and 8-inch semiconductor wafer technology. This AlN pyroelectric detector detects IR over wavelength ranging from 5 $\mu \text{m}$ to 14 $\mu \text{m}$ . In addition, this detector is designed to have added mechanical