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Origami structures held promise for their flexibility, simultaneous responsiveness, and adaptability, yet they are vulnerable due to the hygroscopic property when exposed to the humid environments. However, the patterning of hydrophobic material along the design enhances the controllability of paper for self-folding to robotics locomotion. The capillary action of sprayed water molecules is localized through the number or sizes of hydrophilic channels defined by the printed wax patterns resulting in large deformation to form various 3D geometries. The patterned paper performed folding actuation with water and unfolding behavior with evaporation without being mechanically manipulated by external forces or moments. The paper actuators further enable the sequential self-folding along the multiple hinges for the cube and diamond structures. Advances in soft robotics for practical applications, the utilization of different swelling/shrinking properties with water and kirigami-inspired programmable structures interact with the lightweight and non-planar objects. The anisotropic properties of paper in response to water spraying combined with folding/unfolding deformations permit the fold-to-pop-up robots for biomimetic locomotion on the plane or water. Two robots deform their body to move forward through bending-relaxation gait. [2020-0083] [ABSTRACT FROM AUTHOR]

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 chosen due to its high sensitivity and zero DC power dissipation. Trade-offs among different sensor array designs are investigated to achieve an optimal design, which consists of a $1\times 5$ sensor array occupying an area of 10 mm $\times10$ mm. Each sensor in the array achieves a nominal capacitance value and sensitivity of approximately 1 pF and 30 fF/mmHg, respectively. Fabricated sensor array can be comfortably attached to an individual’s temporal region and ankle area to monitor real-time blood pressure (BP) pulse waveform with high fidelity, from which heart rate and heart rate variability information can be accurately obtained. In addition, the prototype sensor array demonstrates its capability of detecting atrial fibrillation (AFib) from BP pulse waveform measured from an AFib patient. [2020-0179] [ABSTRACT FROM AUTHOR]

A novel microelectromechanical-systems (MEMS)- controlled paper-like transmissive flexible display device wasmodeled by a combination of a cantilever with a flat plate and was realized by roll-to-roll printing process for the first time. This model provides predictions as well as improvement suggestions to both mechanical and electrical designs. A newly developed roll-to-roll printing process which was composed of flexography, gravure, lift-off, and lamination techniques used to manufacture this device was proved applicable on flexible electronics with high-volume, low-cost, and large-area solutions. This 20 V-driven device provided distinguishable three primary colors with averaged transmittance of 50% in visible region for full color flexible display applications and showed commercialization compatibility. Its electrical, mechanical, and optical characteristics excelled previous similar works. The proved major advantages of mechanical reliability, low operation voltage, and process simplicity done by this work made the MEMS flexible display an important alternative to electrophoretic, electrowetting, and electrochromic systems. [ABSTRACT FROM AUTHOR]

In this letter, we present a ZnO nanogenerator built on a paper substrate producing electricity using both contact electrification and piezoelectric effects. Paper is an environmentally friendly material and can help to improve the performance of the ZnO nanogenerator due to its natural roughness. The nanogenerator produced a maximum peak voltag of 38.4 V and a maximum peak current density of 3.2 \mu \textA /cm ^2 from both the inherent piezoelectric property of ZnO and contact electrification between poly(methyl methacrylate) and ZnO nanostructures. [2014-0388] [ABSTRACT FROM AUTHOR]

We report the fabrication of a plasma-generating device on a paper substrate. This device was fabricated using a screen print process. Plasmas were ignited between two parallel electrodes with a plasma gap of 237 to 710 \mu\m using a dc power source. We demonstrated that a stable helium plasma can be sustained when the substrate is flat, rolled, and folded along various orientations. When the plasma was ignited with a 0.2-\mu\L salt solution droplet with 1.4, 4.6, and 7.8 ng of Li, Na, and K respectively applied to the discharge gap, clear metallic emission lines emanated from the plasma. Our result demonstrates that this paper-based plasma device can be used in analytical applications.\hfill[2012-0006] [ABSTRACT FROM AUTHOR]

Describes the above-named upcoming conference event. May include topics to be covered or calls for papers. [ABSTRACT FROM PUBLISHER]

This letter presents a simple and economical paper-based device that is able to generate an array of stable Ar microdischarges. This is a dielectric-barrier-discharge device that exhibits filamentary-type features. The device is sustained by an ac voltage with a 550-V amplitude and 10-kHz frequency. Optical emission spectra show that Ar lines dominate the emission, with a trace amount of CH and \C2 emissions. Despite slight damage, the electrode lifetime exceeds 20 min. Results demonstrate that this device is flexible and is able to achieve maskless patterning of hydrophilic patterns on flat and curved glass surfaces.\hfill[2012-0361] [ABSTRACT FROM PUBLISHER]

Prospective authors are requested to submit new, unpublished manuscripts for inclusion in the upcoming event described in this call for papers. [ABSTRACT FROM AUTHOR]

In this paper, an inkjet-printed electromagnet-based touchpad employing spiral resonators is proposed. The proposed touchpad is fabricated by a direct patterning method using an inkjet printer with a conductive silver nanoparticle ink. The conductive patterns are easily printed on a paper substrate and sintered for achieving good conductivity. The proposed touchpad is composed of two spiral resonators that resonate at 0.94 GHz ( f1 ) and 1.83 GHz ( f2 ), respectively. When the first resonator is touched, f1 decreases from 0.94 to 0.81 GHz because of electromagnetic (EM) coupling between the finger and the spiral resonator. Similarly, when the second resonator is touched, f2 decreases from 1.83 to 1.55 GHz. Owing to the EM coupling distance between the spiral resonator and the finger, the frequency changes although the finger does not reach beyond a height of 1.27 mm on the spiral resonator. The performance of the proposed touchpad is validated using simulation and measurement results. [2016-0035] [ABSTRACT FROM AUTHOR]

Describes the above-named upcoming special issue or section. May include topics to be covered or calls for papers. [ABSTRACT FROM AUTHOR]

Describes the above-named upcoming special issue or section. May include topics to be covered or calls for papers. [ABSTRACT FROM PUBLISHER]

The Nanostructured Origami approach to 3-D nano-manufacturing is a novel way to gain functionality from the third dimension in nanotechnology applications. After first patterning devices onto a structural membrane using traditional 2-D tools, the segments can be folded along predefined creases in order to realize a final shape in 3-D. In order to manufacture increasingly complex devices, knowledge of the origami's dynamics is imperative. This paper describes a method to model the dynamics of two types of origamis using methods that were originally developed for use in robotic manipulation tasks. The stability of the devices in the folded state is also discussed. [ABSTRACT FROM AUTHOR]

This paper reports the development of a broadband highly reflective and structurally flat large-area 2-D subwavelength grating (SWG) reflector, based on a tensioned single-layer silicon metamaterial membrane. Rigorous coupled-wave analysis is adopted to design the metamaterial reflector, resulting in a wavelength range of 600 nm (1.9- $2.5~\mu \text{m}$) with >99% reflectivity, which represents the largest reported fractional bandwidth $\Delta \lambda /\lambda _{\mathrm {c}}$ of 27%. Effects of design parameter deviations on the SWG reflector reflectivity are studied, showing that the reflector design has good fabrication tolerances. A freestanding 2-mm dimension 2-D SWG reflector has been fabricated with high precision, and optical measurements indicate polarization-independent average reflectivity of 99% over the wavelength range of 1.91- $2.49~\mu \text{m}$ , which agrees well with the modeled result. This paper also, for the first time, examines the surface flatness characteristics of a suspended single-layer 2-D SWG reflector. With a tensile stress of 10 ± 5 MPa in the silicon grating membrane, the freestanding reflector achieves nanometer-scale surface flatness, which provides a significant advantage over multilayer DBRs requiring stress-balancing. Furthermore, a hyperspectral Fabry-Perot shortwave infrared filter based on a top suspended 2-D SWG reflector and a bottom 4-pair Si/SiO2 distributed Bragg reflector (DBR) has been experimentally demonstrated for the first time. The filter is measured to have a peak transmission of 80% with a narrow full-width at half-maximum (FWHM) of about 4 nm. This spectral resolution is one order of magnitude higher than that of other reported MEMS/DBR-based Fabry-Perot filters and is well-suited to highly demanding hyperspectral shortwave infrared imaging applications. [2022-0060] [ABSTRACT FROM AUTHOR]

In this paper, a novel fabrication method is proposed for microfluidic tubes with a large diameter, circular cross-section, and thin wall. These properties make the tubes especially suitable for density sensors and Coriolis mass flow sensors, because of the resulting low tube mass, low-pressure drop, and low pressure-dependence of the tube shape. A demonstrator sensor was fabricated and the first measurement results of fluid density and mass flow are presented. The low-cost fabrication method is based on electroplating technology and results in tubes with a near-perfect circular cross-section. Diameters ranging from 120 $\mu \text{m}$ to 1 mm and wall thicknesses from $8~\mu \text{m}$ to 60 $\mu \text{m}$ have been achieved. For the demonstrator sensor presented in this paper a freely suspended tube was realized with a total length of 37 mm, a diameter of 600 $\mu \text{m}$ , and a wall thickness of 20 $\mu \text{m}$. Density measurements were performed using various gases, liquids, and liquid mixtures at 21°C to 23°C lab temperature. The accuracy of the measured densities of gases such as nitrogen, argon, and helium is 5%. For liquids including DI water, isopropyl alcohol (IPA), and their various mixtures an accuracy of 0.5% was obtained. Preliminary mass flow rate measurements were performed with water and isopropyl alcohol up to 30 g/h with less than 30 mbar pressure drop thanks to the large tube diameter. [2021-0179] [ABSTRACT FROM AUTHOR]

Prospective authors are requested to submit new, unpublished manuscripts for inclusion in the upcoming event described in this call for papers. [ABSTRACT FROM PUBLISHER]

This paper presents a multi-objective optimization process using a non-dominated sorting genetic algorithm-II that aims to maximize the vertical displacement of MEMS-type mechanically flexible interconnects (MFIs) while simultaneously preventing these interconnects from experiencing plastic deformation. Given an initial MFI geometric body, this process seeks to optimize the photomask interconnect design so that no modification is required for the existing fabrication process flow. After the design optimization, a reflowed polymer-dome microfabrication process is employed to fabricate the NiW MFIs to provide a more complete analysis of this paper. Simulation data shows that the optimized design can achieve up to 29.7% greater vertical displacement before experiencing plastic deformation relative to the initial design. Experimental data shows an average of 34.2% less vertical plastic deformation relative to the initial design when the MFIs are indented to a depth of $45~\mu \text{m}$. In both simulation and experimental scenarios, the optimized MFIs demonstrate less stress/plastic deformation relative to the initial MFIs for the same given indented depth. [2017–0229] [ABSTRACT FROM AUTHOR]

This paper introduces a batch fabrication method to manufacture Micro-Electro-Mechanical System (MEMS) platforms for 3D integration of sensors spatially-distributed on a 2D plane. In the heart of the concept is a foldable MEMS structure with polymer hinges which is used to support and guide the assembly of the discrete planar sensors by means of folding them into a 3D shape, like origami, providing controlled distribution of sensors in space. Flexible hinges carrying the electrical interconnects are a critical structural element of the platform and material selection study for those is the main focus of this paper. We analyzed different materials for flexible hinges fabrication, including photo-definable polyimide and parylene-C. Three approaches for sensor integration are presented: 1) co-fabrication; 2) sensor drop-in; and 3) transfer bonding. The prototypes of structures with different flexible hinge materials were fabricated and evaluated based on their mechanical flexibility, chemical compatibility, and material outgassing. Parylene-C exhibited similar or better performances compared to polyimide, demonstrating in each of the experiments a higher degree of thermal flexibility up to 350 °C, a superior chemical resistance against hydrofluoric acid, and 2.9 times lower outgassing. [2020-0301] [ABSTRACT FROM AUTHOR]

In this paper, we examine the origins of bias instability in three-axis, mode-matched MEMS gyroscopes. Reducing this drift phenomenon is crucial for highly accurate navigation in applications, such as automated driving or indoor localization. We show that for a typical MEMS gyroscope, bias instability noise becomes the dominant orientation error component after less than 10 s of integration time. A model-based approach summarizing the most common sources of zero-rate offset is combined with a detailed experimental analysis. We find naturally occurring flicker noise acting on the frequency tuning electrodes to be the dominant source of bias instability for the in-plane axis. By controlling the frequency tuning state, we establish an unprecedented value for bias instability of an automotive-type MEMS gyroscope of lower than 0.1 dph—more than a factor 10 improvement from its performance in ordinary operation. Furthermore, we analyze the so far sparsely studied effect of scale-factor instability, which is an increase of drift that scales with applied angular rate. This phenomenon is particularly important for applications, where high angular rates are common, such as dead-reckoning with smart-phones. As out-of-plane MEMS gyroscopes are significantly more challenging to manufacture, their performance has been studied much less. The out-of-plane axes in this paper are shown to exhibit a complex composition of bias instability sources with a total level as low as 0.7 dph. The presented gyroscopes were furthermore designed for ultra-low white noise. The angle random walk (ARW) is lower than 2.5 md/s/rtHz in all three axes. [2018-0165] [ABSTRACT FROM AUTHOR]

Wrinkle patterns, as a simple surface patterning process, have been previously used in triboelectric nanogenerator (TENG) to improve electric performance. However, since lacking an effective way to control the wrinkle pattern in a wide range, the influence of wrinkle pattern to the performance of TENG has not been systematically investigated. This paper proposes a pre-heating process to adjust the modulus of uncured polydimethylsiloxane, resulting in wide-range controllable wrinkle patterns. Quantitative measurements show the wrinkle pattern wavelength ( \lambda ) could be varied from 20.13 to 0.92~\mu \text{m} by pre-heating time from 0 to 10 min. Using this wide-range wrinkle pattern, the performance of TENG was remarkably improved with a higher surface charge density of 537.6~\mu \text{C}/\text{m}^{2}$ . Through simulating the impact of interfacial structures deformation, we found smaller structure leading to higher performance of TENG at low pressure region and smaller surface area resulting in a lower performance, which accounted for the correlation we observed in this paper, and could guide the structure design for a high-charge-density TENG. This paper provides an alternative way for controlling wrinkle pattern as well as increasing surface charge density of TENG from fabrication process, simulated results, theoretical analysis, and quantitative measurements. [2017-0154] [ABSTRACT FROM PUBLISHER]

In this paper, we present positionable photonic waveguide arrays that are developed for optical chip-to-chip alignment. Partly suspended photonic structures, based on the Si3N4/SiO2 material platform, are equipped with thermal actuators enabling the free end of the structures to be positioned with submicrometer accuracy. A finite-element model is developed to provide insight in the way the design of the system affects the performance. The modeling results show that the expected vertical deflection and rotation are highly dependent on the array design. Measurements of fabricated devices confirm the trends that follow from the model and are used to assess the positioning performance. Moreover, the finite-element analysis gives guidelines for the design parameters of an optimal positionable photonic waveguide array. By following these guidelines, all the requirements for the intended photonic alignment can be fulfilled, which is validated by measurements. The stability over time of the positioning system is experimentally determined and is also sufficient. Measured mode field profiles of partly suspended waveguide beams with 1 \mu \textm \,\, \times 220 nm (width $\times $ thickness) sized waveguide cores show correct waveguiding functionality. Finally, an alignment experiment demonstrates how three adjacent waveguide beams within a positionable waveguide array can be actively aligned with the channels of another photonic chip. [2017-0046] [ABSTRACT FROM PUBLISHER]

Different from the device-level research on MEMS shock reliability, this paper introduces an on-chip generation method of shock load, which realizes the in-situ shock test directly loaded on the microstructure. To achieve energy storage and rapid release, a crossbow-type shock load generating structure that can integrate the test sample is proposed. The shock behavior is characterized by the high-speed camera, and the simulation model is established by the finite element software LS-DYNA. Under the shock acceleration of more than 100,000 g, the high-speed switching waveform generated by the microscale mechanical shock was observed with an oscilloscope for the first time. And the shock contact process and the dynamic fracture process of single-crystal silicon (SCS) structures in less than $1\mu \text{s}$ were exhibited. This work has the potential to be used to evaluate the shock resistance reliability of MEMS microstructures in mechanical shock environments, as well as to study material dynamic properties and material failure behaviors at the microscale. [2022-0076] [ABSTRACT FROM AUTHOR]

This paper presents a microfabricated nozzleless acoustic droplet ejector with electrically tunable droplet size as a new tool for on-demand picking and placing semiconductor chips for semiconductor packaging. The ejector is based on a 2-mm-thick lead zirconate titanate (PZT) sheet with a planar annular-ring air-cavity acoustic Fresnel lens on top. When driven with sinusoidal pulsed voltage signals of 1.16 MHz, the ejector generates focused ultrasound with 1-mm focal diameter and 5-mm focal depth at 22 mm focal length in sodium polytungstate (SPT) solution. A finite-element-method (FEM) simulation model calculating the acoustic-field-induced fluid motion during the droplet ejection process has been developed, and verified by experiments, in which the device ejects SPT droplets whose diameter is from 850 to 2, 490 μm, controlled by the driving pulse width and voltage. The ejected droplets are able to carry 400-μm-thick square silicon chips with side length from 700 to 3, 100 μm. A polyester channel-embedded guiding cover for semi-automatic loading of silicon chips to the ejection site is designed to avoid manual placement of the silicon chips. With the proof-of-concept system, we demonstrate ejecting silicon chips out of SPT surface onto a nearby paper, assembling them into arrays with good repeatability. [2020-0337] [ABSTRACT FROM AUTHOR]

Describes the above-named upcoming conference event. May include topics to be covered or calls for papers. [ABSTRACT FROM PUBLISHER]

Describes the above-named upcoming conference event. May include topics to be covered or calls for papers. [ABSTRACT FROM PUBLISHER]

Describes the above-named upcoming conference event. May include topics to be covered or calls for papers. [ABSTRACT FROM PUBLISHER]

In this paper, we demonstrate biocompatible micromachined buckled membranes for the operation in liquids. The membranes feature diameters between 600 and 800 $\mu \text{m}$ as well as integrated piezoelectric thin film actuators, thus enabling switching between the bistable states. The membrane material is known to be not biocompatible, hence a hydrogenated amorphous silicon carbide (a-SiC:H) layer is deposited on the surface. For demonstration purposes, a 70 nm ±3 nm thin a-SiC:H coating with a specific silicon to carbon ratio was chosen, with a negligible impact on the overall switching performance of the bistable membranes. Furthermore, a relation between the membrane center velocity at the first characteristic resonance frequency and the switching ability of a membrane in different viscous fluids is shown. Based on a small signal analysis the switching behavior can be predicted. The membranes were successfully switched in liquids with a dynamic viscosity up to 286 mPa $\cdot \text{s}$. The biocompatibility of the membranes was examined by growing Caco-2 cells, a human carcinoma cell line, on a-SiC:H thin films, featuring different carbon contents and organic surface treatments. The proliferation and adhesion of the cells on the substrates are examined in an empirical cell growth and removal study. Only a-SiC:H surfaces pre-treated with an O2-plasma and coated with Collagen Type I indicated to provide an environment of improved cell adhesiveness compared to other surface treatments. The biological investigations resulted in good cell proliferation, that also depends on the altered hydrophilicity of the surface, as well as on the carbon content of the a-SiC:H thin films. This study reveals that a broad range of biocompatible a-SiC:H surfaces can be prepared, whereby the cell growth can be tailored in terms of proliferation and adhesion for different biomedical application scenarios. Finally, this paper reports on the mechanical features of bistable, buckled membranes and their suitability as a growth substrate for human cell cultures, due to the good biocompatibility of a-SiC:H thin films. We therefore suggest that it will be feasible to grow cells on bistable MEMS membranes, enabling cell experiments in liquid medical environments, with both mechanically excitable and biocompatible surfaces. [2022-0006] [ABSTRACT FROM AUTHOR]

In this paper, energy localization within weakly coupled nonlinear MEMS resonators has been utilized for sensing applications. The sensitivity and the noise floor of the weakly coupled resonators operating beyond the critical amplitude have been characterized at the boundaries of the unstable branch, termed as bifurcation points in this paper. The measurement results show that such measurements can provide beneficial gains in resolution when compared with linear operation, despite the reduced sensitivity at the top bifurcation point. A minimum input-referred noise floor of 18 ppb/Hz1/2 has been achieved through this sensing scheme which is a 40 % betterment in comparison to its linear counterpart. [2018-0084] [ABSTRACT FROM AUTHOR]

A MEMS, silicon-based device with a piezoelectric layer and an integrated magnet is presented for magnetic to electrical transduction. The cantilever structure can be configured either as an energy harvester to harvest power from an AC power line or as an AC current sensor. The positioning of the transducer with respect to the conductor is critical in both scenarios. For the energy scavenger, correct positioning is required to optimize the harvested power. For the current sensor, it is necessary to optimize the sensitivity of the sensor. This paper considers the effect of the relative position of the transducer with respect to the wire on the resulting electromagnetic forces and torques driving the device. It is shown in this paper that it is the net equivalent torque at the anchor that must be considered and not just the vertical component of the magnetic force as has been widely assumed heretofore. We show that for single wire conductors, the commonly made assumption that there exists two symmetrical power peaks at 45° either side of the wire is untrue, but rather that the net driving torque on one side of the wire can be more than an order of magnitude greater than the other. [2018-0173] [ABSTRACT FROM AUTHOR]

In this paper, we have studied the effect of surface wettability and geometrical parameters on the velocity of the ejecting jet during droplet impacts on meshes. This paper presents detailed experiments and modeling which helps in explaining a previous demonstration, where an assembly of meshes with different wettabilities was used to significantly reduce the amount of liquid leakage during impact of droplets travelling at terminal velocity. Drop impact on meshes at various Weber numbers (We) was captured using high-speed imaging. At higher We, the velocity of the ejected liquid jet (${V}_{j}$) was found to be higher than the velocity of the impacting droplet (${V}_{d}$) for most of the superhydrophobic meshes. In contrary, for all values of We the velocity of the ejected liquid through superhydrophilic meshes was lower than the droplet velocity for all meshes. While jet width for superhydrophobic mesh was close to the pore opening dimension, in case of superhydrophilic mesh merging of the ejected jets meant that the width was close to the impacting droplet diameter. A combination of superhydrophilic and superhydrophobic mesh was used to significantly reduce liquid ejection for droplet impact at terminal velocity (~8 m/s). Less than $6\times 10^{-5}$ % volume ejection was observed for the designed combination. This configuration can be used to fabricate rain repellent air-transparent surfaces. [2018-0060] [ABSTRACT FROM AUTHOR]

This paper presents a novel fabrication method for vacuum-sealed capacitive micromachined ultrasonic transducer (CMUT) arrays that are amenable to 3D integration. This paper demonstrates that MEMS structures can be directly built on a glass substrate with preformed through-glass-via (TGV) interconnects. The key feature of this new approach is the combination of copper through-glass interconnects with a vibrating silicon-plate structure suspended over a vacuum-sealed cavity by using anodic bonding. This method simplifies the overall fabrication process for CMUTs with through-wafer interconnects by eliminating the need for an insulating lining for vias or isolation trenches that are often employed for implementing through-wafer interconnects in silicon. Anodic bonding is a low-temperature bonding technique that tolerates high surface roughness. Fabrication of CMUTs on a glass substrate and use of copper-filled vias as interconnects reduce the parasitic interconnect capacitance and resistance, and improve device performance and reliability. A 16\boldsymbol \times 16 -element 2D CMUT array has been successfully fabricated. The fabricated device performs as the finite-element and equivalent circuit models predict. A TGV interconnect shows a 2- \boldsymbol \Omega parasitic resistance and a 20-fF shunt parasitic capacitance for 250- \mu \textm via pitch. A critical achievement presented in this paper is the sealing of the CMUT cavities in vacuum using a PECVD silicon nitride layer. By mechanically isolating the via structure from the active cells, vacuum sealing can be ensured even when hermetic sealing of the via is compromised. Vacuum sealing is confirmed by measuring the deflection of the edge-clamped thin plate of a CMUT cell under atmospheric pressure. The resonance frequency of an 8-cell 2D array element with 78- \mu \textm diameter circular cells and a 1.5- \mu \textm plate thickness is measured as 3.32 MHz at 15-V dc voltage (80% Vpull-in). [2016-0200] [ABSTRACT FROM PUBLISHER]

This paper deals with the influence of the shape of the driving waveform on the frequency responses of microelectromechanical systems (MEMS) resonators under nonlinear actuation. Our models show that, at large oscillation amplitudes, these responses are strongly dependent on the shape of the actuation waveform so that the nonlinear frequency response is not the system signature, but the system signature under a specific driving waveform. The case of a MEMS resonator electrostatically driven with a sine-, pulsed-, or square-wave voltage is specifically addressed. Our models and simulations, supported by experimental evidence, predict counterintuitive phenomena resulting from the distortion of the actuation waveform by the displacement-dependent electrostatic nonlinearity. This paper emphasizes that this issue should not be overlooked in order to perform quantitative MEMS characterization in the nonlinear regime. [2015-0283] [ABSTRACT FROM AUTHOR]

In this paper, a mechanical-electrical-process integrated model of the piezoresistive pressure sensor sensitivity is established for the first time, and the nonlinearity is analyzed from two aspects of bridge arm resistance and piezoresistive stress difference. Furthermore, a new peninsula structure diaphragm (NPSD) piezoresistive differential pressure sensor is proposed. By creating stress concentration areas and adding the cross beam-circular boss structure, within the pressure range of 0–5 kPa, the sensitivity of the sensor measured by the experiment reaches 22.7 mV/kPa, and the nonlinearity is only 0.11%FSO (full-scale output). In addition, it has been proved theoretically and experimentally that the SiO2/Si3N4 passivation film seriously affects the zero output voltage of the sensor, and causes the nonlinearity of 1.22% FSO. At the same time, compared with several typical structures, the pressure sensor proposed has the advantages of high sensitivity, low nonlinearity and small diaphragm. [2021-0206] [ABSTRACT FROM AUTHOR]

This paper presents an in-depth thermomechanical analysis of zero-power micromechanical photoswitches (MPs) aiming at aggressive performance enhancement for applications that require ultralow infrared (IR) detection threshold. An accurate analytical model was first derived and used to maximize the thermal sensitivity of the MPs through a loop-based optimization program. With specific pre-defined boundary conditions, such a program can be used to generate a set of device geometrical parameters leading to highest possible thermal sensitivity without sacrificing the structural strength of the device (i.e., spring constant), which otherwise will have to be done with time-consuming numerical simulations. The optimized MPs show more than 4 times improvement in thermal sensitivity compared to previous demonstrations, thanks to the high thermal resistance and temperature sensitivity achieved using the thermomechanical model. The demonstrated theoretical analysis and thermomechanical optimization methods for the MPs are critical for the development of the next-generation zero-power IR sensors specifically designed for applications that require ultra-sensitive IR detection capability without compromising their sensor size, weight and power consumption. [2021-0231] [ABSTRACT FROM AUTHOR]

Compliant off-chip interconnects as the first-level and second-level compliant interconnect structures are able to accommodate the differential displacement between the die and the substrate or between the substrate and the board due to their high in-plane and out-of-plane compliance. This paper presents experimental and simulation results of drop testing of silicon substrates with micro-scale copper compliant interconnects assembled on organic boards. The micro-scale copper compliant interconnects in this paper are three-arc-fan compliant interconnects with arcuate beam width equal to 10, 15, and 20 \mu \textm , respectively. The samples with three-arc-fan compliant interconnects were subjected to drop tests at varying drop heights ranging from 20 to 50 cm in steps of 10 cm. The experimental and simulation results were compared against the corresponding results obtained from the samples assembled with the solder ball interconnects. Through drop-test experiments and simulations, it is shown that the three-arc-fan compliant interconnects when scaled down in size and fabricated through copper electroplating process are able to isolate the strain transferred from an organic board to a silicon substrate, and that the impact isolation increases with the increased compliance of the interconnects. [2015-0205] [ABSTRACT FROM PUBLISHER]

In this paper, recent developments in the design and fabrication of micromachined fused quartz hemi-toroidal shells are presented. The fabrication is based on micro glassblowing process, demonstrated to enable the realization of high-Q MEMS resonators and gyroscopes. The design optimization of the shell geometry is performed using parametric finite element analysis. The effect of geometric parameters on the scaling of the resonant frequencies and energy dissipation are discussed. Three variations of the micro-glassblowing process are studied in the paper, concluding that shell resonators with a broad operational frequency range without losing the symmetry and Q-factor are feasible. Finite element models are presented to simulate the presented glassblowing processes, which are used to predict the final geometry of shell resonators accurately. Operational frequency as low as 5 kHz and Q-factor as high as 1.7 million is demonstrated on the fabricated shell resonators. The proposed process modifications demonstrate a low-cost and scalable fabrication of 3D shells for resonators and gyroscopes, which can be used in inertial navigation and timing applications. [2019-0179] [ABSTRACT FROM AUTHOR]

Anisotropic wetting is important in industrial, medical and agricultural applications. In this paper, a novel microstructure performing prominent ultra-anisotropic wetting properties is proposed, with MEMS fabrication process. This microstructure possesses both sharp edge and sharp corner (SESC) in topography. The sharp edge can hinder liquid spreading significantly, whereas the sharp corner enhance spreading. By lithography technology on polymer film, Parylene-C, the microstructure can be tailored into different shapes to achieve various liquid spreading properties, two of which are demonstrated here. 2-D SESC microstructure illustrates ultra-high contact angle difference in parallel and perpendicular directions as high as 93.8°, as well as bidirectional wetting properties. Another microstructure, namely 3-D SESC microstructure, demonstrates specific unidirectional wetting properties. The unique microstructure proposed in this paper provide new ideas for application of controlling liquid spreading on surface. [2019-0077] [ABSTRACT FROM AUTHOR]

Profiles the members of the editorial board of the "Journal of Microelectromechanical Systems." Abraham Lee; Jack W. Judy; Gabriel M. Rebeiz; Hans Zappe.

After two decades of intensive development, 3-D integration has proven invaluable for allowing integrated circuits to adhere to Moore’s Law without needing to continuously shrink feature sizes. The 3-D integration is also an enabling technology for hetero-integration of microelectromechanical systems (MEMS)/microsensors with different technologies, such as CMOS and optoelectronics. This 3-D hetero-integration allows for the development of highly integrated multifunctional microsystems with small footprints, low cost, and high performance demanded by emerging applications. This paper reviews the following aspects of the MEMS/microsensor-centered 3-D integration: fabrication technologies and processes, processing considerations and strategies for 3-D integration, integrated device configurations and wafer-level packaging, and applications and commercial MEMS/microsensor products using 3-D integration technologies. Of particular interest throughout this paper is the hetero-integration of the MEMS and CMOS technologies. [2015-0158] [ABSTRACT FROM PUBLISHER]

Resonant body transistors (RBTs) are solid state, actively sensed microelectromechanical systems (MEMS) resonators that can be implemented in commercial CMOS technologies. With small footprint, high- $Q$ , and scalability to gigahertz frequencies, they form basic building blocks for radio frequency (RF) front-ends and timing applications. Toward the goal of seamless CMOS integration, this paper presents the design and implementation of phononic crystals (PnCs) in the back-end-of-line (BEOL) of commercial CMOS technologies with bandgaps in the gigahertz frequencies to be used for enhanced acoustical confinement in CMOS-RBTs. Lithographically defined PnC dimensions allow for bandgap engineering, providing flexibility in resonator design, and allowing for multiple frequencies on a single chip. The theoretical basis for analyzing generic PnCs is presented, with focus on the special case of implementing PnCs in CMOS BEOL layers. The effect of CMOS process variations on the performance of such PnCs is also considered. The analysis presented in this paper establishes a methodology for assessing different CMOS technologies for the integration of unreleased CMOS-MEMS resonators. This paper also discusses the importance of uniformity of the acoustical cavity in the nonresonant dimension and its effect on overall resonator performance. A PnC implementation in IBM 32-nm silicon on insulator (SOI) BEOL layers is demonstrated to achieve 85% fractional-bandgap \sim 4.5$ -GHz frequency. With better energy confinement, the proposed CMOS-RBTs achieve a quality factor Q$ of 252, which corresponds to 8\times . This paper concludes with a discussion of the properties required of a CMOS technology for high performance RBT implementation. [2014-0364] [ABSTRACT FROM PUBLISHER]

This paper derives an analytical model of a capacitive pressure transducer based on equations for deflection and fundamental mode shape of a clamped circular plate. The derived model enables efficient large-signal electromechanical simulations and calculation of an equivalent circuit. The model shows good agreement with finite element analysis and experiments. The spring-mass-damper system used in the model is calculated for uniform, anisotropic, and layered plate materials. A cubic spring constant captures large plate deflections. Use of the clamped-plate shape function leads to a simple expression for capacitance as a function of deflection and to closed-form equations for pull-in voltage. Comparison of the model with finite element analysis for several air-coupled capacitive micromachined ultrasonic transducer designs shows better than 10% agreement for deflection, resonant frequency, and pull-in voltage. The model also compares well with characterized devices. The analytical model could be further improved with additional damping sources and methods to model a compliant plate boundary. [2017-0161] [ABSTRACT FROM AUTHOR]

In this paper we present laterally vibrating resonators (LVRs) based on X-cut lithium niobate (LN) exhibiting a maximum quality factor $({Q})$ around 1200 and an electromechanical coupling ( $k_{t}^{2}$ ) of 30%. This paper shows how the highest $k_{t}^{2}$ ever attained in X-cut LN resonators can be combined with very high ${Q}$ to achieve a resonator figure of merit (FoM $= k_{t}^{2}\cdot {Q}$ ) of 360. In this paper, we validate the theoretical prediction of $k_{t}^{2}$ versus the resonator orientation in the YZ plane and investigate what geometrical parameters mostly impact the ${Q}$ of these devices. [2017–0181] [ABSTRACT FROM AUTHOR]

In this paper, a novel, computationally efficient, and simple closed-form expression has been derived to accurately calculate the pull-in voltage value of microelectromechanical system (MEMS) cantilever. At first, MEMSs actuators with various physical parameters have been simulated by a software that employs the finite element method, and then, the pull-in voltage expression has been derived by using the differential evolution optimization algorithm together with the simulation data. Since the formula is derived from the simulation data, it implicitly contains the fringing field effect. In order to verify the accuracy and robustness, the predictions of closed-form formula proposed in this paper have been compared with those of the theoretical ones through the simulation and experimental studies previously presented in the literature. The key advantage of the presented model is delivering a satisfying estimation of the pull-in voltage in a simple fashion. [2017–0245] [ABSTRACT FROM AUTHOR]

We report a new method for fabrication of research-grade glass microfluidic devices using a household microwave oven. The transformative step in this technique is the formation of the microchannel and fusion bonding of the glass layers in a single step. This is demonstrated here using a non-photolithographic technique for both high aspect ratio rectangular and circular cross-section microchannels. In this paper, the microfluidic devices are fabricated utilizing a thin paper cutout as the sacrificial channel layer, glass blanks, and a microwave kiln sold commercially for arts and crafts. Glass microfluidic devices are fabricated in a microwave oven in as short as 2 min. [2017–0209] [ABSTRACT FROM AUTHOR]

This paper presents a microfabricated sensor that uses electrical microdischarges to sense the deflection of a diaphragm under applied pressure. The sensor responds by redistributing electron current of pulsed microdischarges between one cathode ( $K$ ), a reference anode (A1), and a deflecting anode (A2), all of which are located in a cavity under the diaphragm; the differential anode current indicates the applied pressure. In this paper, the sensor is monolithically fabricated from a single silicon wafer, using a combination of surface micromachining and through-wafer isolated bulk-silicon lead transfer (TWIST) technology. The TWIST technology provides lead transfer into the sealed cavity as well as backside contacts, allowing miniaturization of the device footprint and surface mount assembly within systems. The active footprint of the complete sensor measures 300\times 300 \,\,\mu \text {m}^{2} in size, making it the smallest sealed microdischarge-based pressure sensor reported to date. The normalized differential current from the anodes monotonically increases from −0.7 to 0.2 as the external pressure increases from 1 to 8 atm. [2017–0274] [ABSTRACT FROM PUBLISHER]

Touchscreens have been prevalent in daily life and ubiquitously applied in consuming electronics, industrial control systems, and other applications as human computer interfaces (HCIs), which offers a convenient way for the human to interact with the smart devices. However, the lack of tactile force feedback from these conventional touchscreens draws limitations on the dexterity and intuitiveness of those devices, which results in multi-level menus, waiting, multi-finger gestures, and so on. To enhance and diversify functions of touchscreens, this paper presents a multi-axis tactile sensor array prototype with a unique layered structure, which is capable of sensing both 3-directional tactile force and location information over an area of 60 mm $\times60$ mm by utilizing only $2\times2$ piezoresistive MEMS force sensors. This paper integrated the sensibility of tangential force and normal force within one system, which sheds light on multi-axis tactile applications and dramatically reduced the number of tactile cells. The sensor array design, fabrication and packaging, and test approaches have been discussed in this paper. Qualitative and quantitative analysis have been conducted to evaluate the performance of the tactile sensor array with tested force range of 0.1 ~ 0.5 N. The results demonstrated the functionality of proposed sensor array, which exhibited promising potential for touchscreen applications. [2017-0176] [ABSTRACT FROM PUBLISHER]

In this paper, we study the snapping action of a micromachined bistable mechanism harmonically driven with an ultra-small actuation stroke, which is realized through the mode amplification in a two-degrees-of-freedom (2-DOF) vibration system using an on-chip electrostatic actuator. The micromachined bistable mechanism is based on a curved beam configuration. The dynamic response of the device is theoretically predicted with the harmonic balance method. Further, to demonstrate this proposed study, a microelectromechanical systems (MEMS) prototype device is designed, fabricated, and tested. In experiments, the forward and backward state switching actions of the prototype device are realized with actuation stroke smaller than 0.4~\mu \textm , while the traveling distance between the two states is about 18~\mu \textm . To the best of our knowledge, we demonstrate for the first time the state switching of a cured beam bistable mechanism using harmonic driving in a 2-DOF vibration system. This paper has potential in applications including MEMS switches and MEMS filters. [2017-0221] [ABSTRACT FROM PUBLISHER]