An RF oscillator has been demonstrated using a wideband SH 0 mode lithium niobate acoustic delay line (ADL). The design space of the ADL-based oscillators is theoretically investigated using the classical linear time-invariant (LTI) phase noise model. The analysis reveals that the key to low phase noise is low insertion loss (IL), large delay ( ${\tau }_{\mathbf {G}}$ ), and high carrier frequency

This letter shows that active tuning of MEMS resonators through temperature is highly dependent on the actuation mechanism used, and demonstrates the adverse effects of using substrate conductive heating characterization results to predict device’s performance in their final application, where Joule heating is most likely to be used. A buckled VO 2 -based SiO 2 tunable MEMS resonator is used in the

This paper reports on the demonstrations of first-order antisymmetric Lamb wave (A1) mode resonator as a new platform for front-end filtering of the fifth-generation (5G) wireless communication. The sub-6 GHz resonance in this work is achieved by employing the A1 mode in the micromachined Y-cut Lithium Niobate (LiNbO 3 ) thin films. The spurious modes mitigation is achieved by optimizing the distribution

We are reporting on the first use of the piezo-avalanche effect in a micromachined sensor for the measurement of inertial forces. The device integrates a pn junction at the base of a beam that is used as the spring for the microstructure. Movements of a proof-mass at the opposite end of the beam produce stress at the location of the junction. To measure this stress, the junction is forced into its

This work presents a new acoustic MEMS resonator technology, dubbed Aluminum Nitride (AlN) Combined Overtone Resonator (COR), capable of addressing the filter requirements for the 5G high frequency bands in the 6-40GHz range. The COR exploits the multimodal excitation of two higher-order Lamb waves ( $2^{\mathbf {nd}}$ and $3^{\mathbf {rd}}$ order Asymmetrical Lamb Waves) in a suspended thin-film AlN

Flat surfaces decorated with micro- and nanostructures are important tools in biomedical research used to control cellular shape, in studies of mechanotransduction, membrane mechanics, cell migration and cellular interactions with nanostructured surfaces. Existing methods to fabricate surface-bound nanostructures are typically limited either by resolution, aspect ratio or throughput. In this work,

Passive implantable or portable infusion pumps comprise an energy source to pressurize a drug and a fluidic restriction to determine the delivery rate. MEMS technology enables the design of microfluidic chips that can passively regulate the flow rate and therefore limit the impact of pressure variations on flow accuracy. The device is a triple-stack structure made of silicon and borosilicate with valves

Chronic lung disease is commonly treated using portable inhaler systems. By design, these inhalers come into repeated contact with the mouth region of patients and are therefore subject to bacterial contamination and ingrowth. To enable the safe delivery of an aerosol from a drug reservoir of such an inhaler, the reservoir needs to be protected from pathogens. Here we demonstrate a self-sealing aerosol

We demonstrate two novel dual-mode ovenized MEMS resonators, each with an in-chip device layer micro-oven that utilizes less than 30mW for resonator temperature control over variations in external temperature from −40°C to +60°C. The device layer micro-oven enables correction for ambient temperature variations and achieves a 1-week frequency stability for the output mode over temperature near 1.5 ppb

A method that allows the investigation of discharge transport mechanism in dielectric films used in MEMS capacitive switches or MIM capacitors or even bare dielectric films is presented. The method is based on monitoring the dielectric film surface or MIM top electrode potential decay rate and the dependence of conductivity on surface potential. The method has been applied in MEMS and MIMs with simultaneously

In this paper, we introduce a compliant mechanical amplifier (mechAMP) suitable for the sensitivity enhancement in MEMS sensor applications. The design, fabrication and characterization of a planar compliant amplifier mechanism is presented with special focus on the kinematic and static system modelling of the displacement and force amplification. We show that the proposed system can also be applied

Reactive Ion Etching (RIE) of Cytop as the cladding material for optical waveguides and microfluidic channels is investigated. Different grades of Cytop (M, A and S), different mask materials including photoresist and metals, different RIE parameters, along with different substrate materials were investigated. Grass-like structure was observed at the bottom of etched channels, of height that depends

We present the conceptual approach, theoretical simulations, and experimental results of a novel device based on acoustic delay lines with different pitch between transmitter and receiver (dubbed pitch-asymmetric delay lines) for passive voltage amplification of radio frequency signals. The theoretical results show that it is possible to attain very high voltage gains in this new class of asymmetrical

In this paper, we report a two-dimensional (2D) Thermoresistive Micro Calorimetric Flow (TMCF) sensor by using a $0.35~\mu \text{m}$ 2P4M CMOS MEMS technology. For the airflow, the fabricated and the open-space packaged 2D flow sensor system achieved the highest normalized sensitivity of 32 mV/W/(m/s) with respect to input heating power and gain. To overcome the sensor output drifting issue due to

Non-linearity in actuation of MEMS devices are essential in many applications. Previously, we presented the design and modeling of a NanoThermoMechanical AND logic gate, which is one of the building blocks of thermal computing (i.e., data processing based on heat instead of electricity). The gate is achieved through the coupling between near-field thermal radiation and MEMS thermal actuation. In the

We present a novel approach to fundamentally eliminate electrical feedthrough (cross-talk) signal in self-sensing piezoelectric microcantilevers, used in dynamic mode atomic force microscopy (AFM). The probe is an Si microcantilever on which a two-layer piezoelectric stack transducer is microfabricated. The top transducer in the stack functions as an actuator, while the bottom transducer is used as

Electroactive-Polymers (EAPs) are one of the best soft $\mu $ -actuators with great biomedical applications. Ionic ones ( i -EAPs) have more promising features and have adequate potential for using in the active microfluidic devices. Here, as a case study, we have designed and fabricated a microfluidic micromixer using an i -EAP named Ionic Polymer-Metal Composite (IPMC). In microfluidics, active devices

Presents the table of contents for this issue of the publication.

Presents a listing of the editorial board, board of governors, current staff, committee members, and/or society editors for this issue of the publication.

It is thanks to the diligent and painstaking service of its Editorial Board that the Journal of MicroElectroMechanical System (JMEMS) has maintained its prestige over the years and it is recognized as one of the most relevant collection of publications related to MEMS research activities. The Associate Editors of JMEMS work very hard with authors and reviewers to make sure papers of the highest quality

On November 22, 2019, MEMS lost one of its early pioneers, Dr. Harvey C. Nathanson, at age 83. A lifelong resident of Pittsburgh, Pennsylvania, he received his education in electrical engineering from Carnegie Institute of Technology, now Carnegie Mellon University, completing his Ph.D. in 1962. He then joined Westinghouse Research and Development Center, working as a research engineer and then manager

This paper reports a novel mode-localized resonant accelerometer, which can keep high sensitivity even over a wide range. To improve the adjustability of sensitivity, a new four degree of freedom (4-DoF) series-parallel resonator array is proposed. Three sensing resonators are mechanically coupled together in series by folding beams and the fourth sensitivity-tuning resonator is electrically coupled

Although high strain and strain-rate impacts to the human body have been the subject of substantial research at both the systemic and tissue levels, little is known about the cell-level ramifications of such assaults. This is largely due to the lack of high throughput, dynamic compression devices capable of simulating such traumatic loading conditions on individual cells. To fill this gap, we developed

This paper presents a design process for miniaturized atomic vapor cells using the micro-glassblowing process. It discusses multiple design considerations, including cell geometry, optical properties, materials, and surface coating. The geometry and the optical properties were studied using experimentally verified analytical and Finite Element Models (FEM). The cell construction material and surface

Transient heat flux sensors are widely used in unsteady thermal analyses. Commercial sensors currently available for high heat flux, however, have relatively low sensitivity. Micromachined thermopile based sensors with advantages of high sensitivity and small size, have been used for the measurement of heat flux produced by black body (usually in the level of W/m 2 ), but not been tried to measure

Performance of several readout circuits, when applied to a MEMS-based bulk piezoresistive displacement sensor is compared in this study. The sensor comprises a pair of tilted clamped-guided silicon beams whose bulk piezoresistivity is used for displacement sensing. Wheatstone half-bridge, constant-voltage, and constant-current circuits are implemented to measure resistance changes of this sensor. We

Superomniphobic surfaces that repel liquids of extremely low surface tension rely on carefully fabricated doubly re-entrant topographies, typically made by silicon deep reactive ion etching technology. However, previously published processes have depended on critically timed etching steps, which are difficult to downscale. We present a scalable process that eliminates the critically timed etching steps

In this study, the simple and rapid formation of porous silicon on a pillar array structure using inductively coupled plasma reactive ion etching (ICP-RIE) is realized. This method can render the outermost surface porous without using an additional etching or deposition apparatus because the same equipment is used to form the structure. As a basic experiment, we attempted to etch the structure by considerably

Development of microfluidic circuits that are analogous to electronic circuits is useful because of their potential to drastically reduce dynamic off-chip controllers. In microfluidic circuits, a microfluidic oscillator that converts constant input to pulsatile output is the key component. Here, we apply a constant inflow to our previous constant pressure-driven oscillator and demonstrate its distinct

Combining the resolution of conventional gas chromatography systems with the size factor of microGC systems is important for improving the affordability and portability of high performance gas analysis. Recent work has demonstrated the feasibility of high resolution separation of gases in a benchtopscale short column system by controlling thermal gradients through the column. This work reports a microfabricated

The rapid development of microfluidic technology has increased the demand for the integration of driving circuits in the microfluidic devices. We have proposed a novel on-chip electroosmotic (EOF) micropump integrated with a high-voltage (11V) generator. The 11V (49.8 V) generator is based on a Dickson charge pump, which is fabricated on a silicon-on-insulator (SOI) substrate by the standard CMOS process

MEMS atomic vapor cells have a large variety of applications in chip-scale atomic devices such as clocks, gyroscopes or magnetometers. These cells are usually hermetically sealed by anodic bonding of borosilicate to silicon, a proven and reliable method, yet showing specific limitations such as inherent oxygen contamination of the cavity or limitation to a few combinations of materials. As an alternative

Sensitivity improvement and measurable pressure limit extension of Pirani vacuum gauge are urgent needed for meeting the rapid growing requirements in ultra-low and wide-range pressure applications. However, the adjustable range of measureable pressure of the Pirani vacuum gauge is limited to only several orders of magnitude of vacuum range. In this work, a fusion method was proposed to improve the

This article presents the design, realization and measurement of thin-film packaged RF-MEMS switched capacitors for millimeter-wave applications. Packaging is included in the MEMS fabrication process, with silicon nitride thin film shell above MEMS structure. Thin-film packaging is done using a combination of electron beam evaporated metal and silicon nitride PECVD deposition. The package hermeticity

The paper reports on the fabrication and characterization of flexural resonators designed for resonant strain sensing and manufactured using 2 μm thick monocrystalline 3C-SiC layers grown on Silicon-On-Insulator substrates. The resonators are designed with Double-Ended-Tuning Fork geometry and actuated electrostatically using lateral electrodes fixed on the sides of the resonator tines, through coupling

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We demonstrate a MEMS beam scanner capable of biaxial scanning with simultaneous focus control, for integration into a handheld confocal microscope for skin imaging. The device is based on a dual axis gimbal structure with an integrated largestroke deformable mirror. SU-8 polymer is used to construct both the deformable membrane as well as the torsional hinges for biaxial scanning. The 4 mm diameter

This letter reports on the fabrication, simulation and characterization of conformal antireflective black-silicon (BSi) nanowires on a 3D silicon structure. The BSi nanostructures were formed on various facets of a 3D Si structure including sharp tips and sidewalls using a metal-assisted chemical (MAC) etching process. The conformal BSi design was simulated using FDTD Lumerical software. The antireflection

Traveling wave ultrasonic micromotors fabricated from a single layer of homogeneous bulk piezoelectric lead zirconate titanate (PZT) are described. The miniature motors are capable of bi-directional rotary motion with controllable speeds. By taking advantage of transverse interdigitated electrodes to excite traveling waves in a patterned bulk PZT substrate, the monolithic micromotor stators are patterned

We demonstrate the design methodology, geometrical analysis, device fabrication, and testing of a double-sided design (DSD) of tunable-focus dielectrophoretic liquid miniature lenses. This design is intended to reduce the driving voltage for tuning the lens, utilizing a double-sided electrode design that enhances the electric field magnitude. Fabricated devices were tested and measurements on a goniometer

Use of a thin-film piezoelectric microactuator for axial scanning during multi-photon vertical cross-sectional imaging is described. The actuator uses thin-film lead-zirconate-titanate (PZT) to generate upward displacement of a central mirror platform, micro-machined from a silicon-on-insulator (SOI) wafer to dimensions compatible with endoscopic imaging instruments. Device modeling in this paper focuses

We report on a flow velocity measurement technique based on snap-through detection of an electrostatically actuated, bistable micromechanical beam. We show that induced elecro-thermal Joule heating and the convective air cooling change the beam curvature and consequently the critical snap-through voltage (VST ). Using single crystal silicon beams, we demonstrate the snap-through voltage to flow velocity

Microelectromechanical systems (MEMS) that require contact of moving parts to implement complex functions exhibit limits to their performance and reliability. Here, we advance our particle tracking method to measure MEMS motion in operando at nanometer, microradian, and millisecond scales. We test a torsional ratcheting actuator and observe dynamic behavior ranging from nearly perfect repeatability

Low-profile patterned plasmonic surfaces are synergized with a broad class of silicon microstructures to greatly enhance near-field nanoscale imaging, sensing, and energy harvesting coupled with far-field free-space detection. This concept has a clear impact on several key areas of interest for the MEMS community, including but not limited to ultra-compact microsystems for sensitive detection of small

Shadow Mask technology has been used over the years for resistless patterning and to pattern on unconventional surfaces, fragile substrate and biomaterial. In this work, we are presenting a novel method to fabricate high aspect ratio (15:1) three-dimensional (3D) Nickel (Ni) shadow mask with vertical pattern length and width of 1.2 mm and 40 μm respectively. The Ni shadow mask is 1.5 mm tall and 100

We demonstrate an electrowetting-based liquid optical phase shifter. The phase shifter consists of two immiscible liquid layers with different refractive indices. Sandwiched between the two liquids is a rigid membrane that moves freely along the optical axis and supported by a compliant surround. When applied with a pressure, the thicknesses of both liquid layers change, which induces a difference

Atrial fibrillation (AFib) is a significant healthcare problem caused by the uneven and rapid discharge of electrical signals from pulmonary veins (PVs). The technique of radiofrequency (RF) ablation can block these abnormal electrical signals by ablating myocardial sleeves inside PVs. Catheter contact force measurement during RF ablation can reduce the rate of AFib recurrence, since it helps to determine

The cryogenic process and Bosch process are two widely used processes for reactive ion etching of high aspect ratio silicon structures. This paper focuses on the cryogenic deep etching of 400 nm pitch silicon gratings with various etching mask materials including polymer, Cr, SiO2 and Cr-on-polymer. The undercut is found to be the key factor limiting the achievable aspect ratio for the direct hard

A multi-sensor flexible strip is developed for a urethral catheter to measure distributed pressure in a human urethra. The developed sensor strip has important clinical applications in urodynamic testing for analyzing the causes of urinary incontinence in patients. There are two major challenges in the development of the sensor. First, a highly sensitive sensor strip that is flexible enough for urethral

This paper presents the design and characterization of a three-axis thermomechanical actuator-based endoscopic scanner for obtaining ex vivo two-photon images. The scanner consisted of two sub-systems: 1) an optical system (prism, gradient index lens, and optical fiber) that was used to deliver and collect light during imaging and 2) a small-scale silicon electromechanical scanner that could raster

High frequency large scanning angle electrostatically actuated microelectromechanical systems (MEMS) mirrors are used in a variety of applications involving fast optical scanning. A 1-D parametrically resonant torsional micromirror for use in biomedical imaging is analyzed here with respect to operation by duty-cycled square waves. Duty-cycled square wave excitation can have significant advantages

A thin-film piezoelectric microactuator using a novel combination of active vertical translational scanning and passive resonant rotational scanning is presented. Thin-film lead-zirconate-titanate unimorph bending beams surrounding a central platform provide nearly 200-μm displacement at 18 V with bandwidth greater than 200 Hz. Inside the platform, a mirror mount, or mirror surface, supported by silicon

Here, we report on the development and evaluation of novel unobstructing magnetic microactuators for maintaining the patency of implantable ventricular catheters used in hydrocephalus application. The treatment of hydrocephalus requires chronic implantation of a shunt system to divert excess cerebrospinal fluid from the brain. These shunt systems suffer from a high failure rate (>40%) within the first

We describe a design methodology for on-chip magnetic bead label detectors based on Hall-effect sensors. Signal errors caused by the label-binding process and other factors that limit the minimum detection area are quantified and adjusted to meet typical assay accuracy standards. The methodology is demonstrated by designing an 8192 element Hall sensor array, implemented in a commercial 0.18 μm CMOS

Transforming microfluidics-based biosensing systems from laboratory research into clinical reality remains an elusive goal despite decades of intensive research. A fundamental obstacle for the development of fully automated microfluidic diagnostic systems is the lack of an effective strategy for combining pumping, sample preparation, and detection modules into an integrated biosensing platform. Herein

The spatial organization of cellular communities plays a fundamental role in determining intercellular communication and emergent behavior. However, few tools exist to modulate tissue organization at the scale of individual cells, particularly in the case of dynamic manipulation. Micromechanical reconfigurable culture achieves dynamic control of tissue organization by culturing adherent cells on microfabricated

Continuous glucose monitoring (CGM) sensors based on affinity detection are desirable for long-term and stable glucose management. However, most affinity sensors contain mechanical moving structures and complex design in sensor actuation and signal readout, limiting their reliability in subcutaneously implantable glucose detection. We have previously demonstrated a proof-of-concept dielectric glucose

This paper presents a new actuation scheme for in-plane bidirectional translation of polysilicon microelectrodes. The new Chevron-peg actuation scheme uses microelectromechanical systems (MEMS) based electrothermal microactuators to move microelectrodes for brain implant applications. The design changes were motivated by specific needs identified by the in vivo testing of an earlier generation of MEMS

We report here a successful demonstration of a flip-chip packaging approach for a microelectromechanical systems (MEMS) device with in-plane movable microelectrodes implanted in a rodent brain. The flip-chip processes were carried out using a custom-made apparatus that was capable of the following: 1) creating Ag epoxy microbumps for first-level interconnect; 2) aligning the die and the glass substrate;

We present an innovative microfluidic approach to transcranial delivery of small quantities of drugs in brief time pulses for neurobiological studies. The approach is based on a two-stage process of consecutive drug dispensing and delivery, demonstrated by a device featuring a fully planar design in which the microfluidic components are integrated in a single layer. This 2-D configuration offers ease