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Microelectromechanical Systems (microelectromechanical + system)

Distribution by Scientific Domains

Polymers and Materials Science	62%
Engineering	18%

Selected Abstracts

Contact-Printed Microelectromechanical Systems

ADVANCED MATERIALS, Issue 16 2010
Corinne E. Packard
A process for rapid fabrication of metallic MEMS (microelectromechanical systems) without lithographic processing is presented. Using dimensionally scalable contact printing, 3D electromechanical structures (see figure) are fabricated and functionally tested. Flexible, paper-thin device arrays produced by this method may enable such applications as pressure sensing skins for people and vehicles, phased array detectors for acoustic imaging, and novel adaptive-texture display applications. [source]

Microelectromechanical Systems: All-Oxide Crystalline Microelectromechanical Systems: Bending the Functionalities of Transition-Metal Oxide Thin Films (Adv. Mater.

ADVANCED MATERIALS, Issue 23 2009
23/2009)
Freestanding structures can be employed to induce strain at their surfaces upon bending. Luca Pellegrino and co-workers show on p. 2377 that a crystalline SrTiO3 (001) thin film cantilevered structure that can be used as a flexible substrate for the epitaxial deposition of correlated oxide films. Surface strain generated by bending is transmitted to the epitaxial (La,Sr)MnO3 film producing a reversible change of its electrical resistance. [source]

All-Oxide Crystalline Microelectromechanical Systems: Bending the Functionalities of Transition-Metal Oxide Thin Films

ADVANCED MATERIALS, Issue 23 2009
Luca Pellegrino
A crystalline all-oxide microelectromechanical system is presented. A suspended SrTiO3(001) cantilever is employed as flexible substrate for the deposition of epitaxial transition-metal oxide films. A strain generator device for oxide films is thus demonstrated, changing the conductivity of an overgrown epitaxial (La,Sr-)-MnO3 film by bending downward the SrTiO3 element with an AFM tip or a gate voltage bias. [source]

Microautosamplers for discrete sample injection and dispensation

ELECTROPHORESIS, Issue 9 2005
Chun-Wei Huang
Abstract Microfluidic systems show considerable potential for use in the continuous reaction and analysis of biosamples for various applications, such as drug screening and chemical synthesis. Typically, microfluidic chips are externally connected with large-scale autosamplers to inject specific volumes of discrete samples in the continuous monitoring and analysis of multiple samples. This paper presents a novel microelectromechanical system (MEMS)-based autosampler capable of performing the discrete injection and dispensation of variable-volume samples. This microdevice can be integrated with other microfluidic devices to facilitate the continuous monitoring and analysis of multiple biosamples. By means of electroosmotic focusing and switching controlled by the direct application of electric sources on specific fluid reservoirs, a precise sample volume can be injected into the specified outlet port. Fluorescence dye images verify the performance of the developed device. An injection-and-washing scheme is developed to prevent cross-contamination during the continuous injection of different samples. This approach renders feasible the injection of several discrete samples using a single microchip. Compared to its large-scale counterparts, the developed microautosampler is compact in size, has low fabrication costs, is straightforward to control, and most importantly, is readily integrated with other microfluidic devices (e.g., microcapillary electrophoresis chips) to form a microfluidic system capable of the continuous monitoring and analysis of bioreactions. The proposed microautosampler could be promising towards realizing the micrototal analysis system (,-TAS) concept. [source]

High-Speed and Wide-Angle Deflection Optical MEMS Scanner Using Piezoelectric Actuation

IEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, Issue 3 2010
Takayuki Iseki Member
Abstract A fast and wide deflection silicon-resonant torsional optical scanner driven by a piezoelectric actuator has been developed and patented. The scanner is composed of a 1-mm square mirror and two pairs of torsion beams and arms fabricated using microelectromechanical system (MEMS) processing of a silicon-on-insulator (SOI) wafer. According to calculations, at the same resonant driving frequency, the maximum principal stress of this structure was about one-third smaller than that of the usual structure having one pair of torsion beams. We achieved high frequency scanning of the optical beam with a large angular deflection up to 54° at 38 kHz with a 5 V peak-to-peak applied voltage using the bulk piezoelectric stack actuator, and up to 17° at 38 kHz with a 25 V peak-to-peak voltage using the unimorph actuator of a zinc oxide (ZnO) thin film. These results show that this scanner has the ability to perform the horizontal scanning for high-resolution extended graphics array (XGA) or super extended graphics array (SXGA) laser display. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source]

All-Oxide Crystalline Microelectromechanical Systems: Bending the Functionalities of Transition-Metal Oxide Thin Films

Artificial neural network modeling of RF MEMS resonators

INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 4 2004
Yongjae Lee
Abstract In this article, a novel and efficient approach for modeling radio-frequency microelectromechanical system (RF MEMS) resonators by using artificial neural network (ANN) modeling is presented. In the proposed methodology, the relationship between physical-input parameters and corresponding electrical-output parameters is obtained by combined circuit/full-wave/ANN modeling. More specifically, in order to predict the electrical responses from a resonator, an analytical representation of the electrical equivalent-network model (EENM) is developed from the well-known electromechanical analogs. Then, the reduced-order, nonlinear, dynamic macromodels from 3D finite-element method (FEM) simulations are generated to provide training, validating, and testing datasets for the ANN model. The developed ANN model provides an accurate prediction of an electrical response for various sets of driving parameters and it is suitable for integration with an RF/microwave circuit simulator. Although the proposed approach is demonstrated on a clamped-clamped (C-C) beam resonator, it can be readily adapted for the analysis of other micromechanical resonators. © 2004 Wiley Periodicals, Inc. Int J RF and Microwave CAE 14: 302,316, 2004. [source]

Layer-by-Layer Interference Lithography of Three-dimensional Microstructures in SU-8,

ADVANCED ENGINEERING MATERIALS, Issue 5 2009
Andrés F. Lasagni
We report on rapid fabrication of two-, two and a half-, and 3D planar periodic structures using layer-by-layer deposition and interference patterning of SU-8 photoresist. Complex structures with non-periodic vertical symmetry were fabricated controlling the cure depth by addition of a UV absorber. The fabrication method reported here can be applied for the high-volume manufacturing of solid structures for microelectromechanical systems and microfluidic devices. [source]

Foldable Printed Circuit Boards on Paper Substrates

ADVANCED FUNCTIONAL MATERIALS, Issue 1 2010
Adam C. Siegel
Abstract This paper describes several low-cost methods for fabricating flexible electronic circuits on paper. The circuits comprise i) metallic wires (e.g., tin or zinc) that are deposited on the substrate by evaporation, sputtering, or airbrushing, and ii) discrete surface-mountable electronic components that are fastened with conductive adhesive directly to the wires. These electronic circuits,like conventional printed circuit boards,can be produced with electronic components that connect on both sides of the substrate. Unlike printed circuit boards made from fiberglass, ceramics, or polyimides, however, paper can be folded and creased (repeatedly), shaped to form three-dimensional structures, trimmed using scissors, used to wick fluids (e.g., for microfluidic applications) and disposed of by incineration. Paper-based electronic circuits are thin and lightweight; they should be useful for applications in consumer electronics and packaging, for disposable systems for uses in the military and homeland security, for applications in medical sensing or low-cost portable diagnostics, for paper-based microelectromechanical systems, and for applications involving textiles. [source]

Fabrication of Microcantilever Sensors Actuated by Piezoelectric Pb(Zr0.52Ti0.48)O3 Thick Films and Determination of Their Electromechanical Characteristics,

ADVANCED FUNCTIONAL MATERIALS, Issue 12 2005
H. Park
Abstract The integration and the device realization of Pb(Zr,,Ti)O3 (PZT) thick films on Si substrates are known to be extremely difficult because the processing temperature of the PZT thick film is close to the melting point of Si. However, PZT thick-film devices on Si warrant attention as they are appropriate for biological transducers; they generate large actuating forces and have a relatively high sensitivity for mass detection, especially in liquids. In this study, Pb(Zr0.52Ti0.48)O3 thick-film cantilever devices are successfully fabricated on a Pt/TiO2/SiNx/Si substrate using a screen-printing method and microelectromechanical systems (MEMS) process. Elastic and electromechanical properties such as the Young's modulus and transverse piezoelectric coefficient are determined from microstructural and electrical analyses for further mechanical study. The calculated Young's modulus of the thick film, 53.9,±,3.85,GPa, corresponds to the resonant frequency obtained from the measured harmonic oscillation response. The transverse piezoelectric constant, d31, of ,20.7 to ,18.8,pC,N,1 is comparable to that of a dense thin film. These values promise the possibility of determining the resonance properties of a thick-film cantilever by designing its structure and then simulating the harmonic oscillation response. Using the PZT thick-film cantilever, a strong harmonic oscillation with a quality (Q) factor of about 23 is demonstrated in water. The observation of strong harmonic oscillation in liquid implies the feasibility of precise real-time recognition of biomolecules using PZT thick-film cantilevers. [source]

Cover Picture: Fabrication of Stable Metallic Patterns Embedded in Poly(dimethylsiloxane) and Model Applications in Non-Planar Electronic and Lab-on-a-Chip Device Patterning (Adv. Funct.

ADVANCED FUNCTIONAL MATERIALS, Issue 4 2005
Mater.
Abstract A composite image is shown that highlights examples of device architectures that either incorporate or exploit polymer-embedded metallic microstructures. In work reported by Nuzzo and co-workers on p.,557, new applications of soft lithography, in conjunction with advanced forms of multilayer metallization, are used to construct these exceptionally durable structures. They are suitable for use in non-planar lithographic patterning, and as device components finding applications ranging from microelectronics to Lab-on-a-Chip analytical systems. This article describes the fabrication of durable metallic patterns that are embedded in poly(dimethylsiloxane) (PDMS) and demonstrates their use in several representative applications. The method involves the transfer and subsequent embedding of micrometer-scale gold (and other thin-film material) patterns into PDMS via adhesion chemistries mediated by silane coupling agents. We demonstrate the process as a suitable method for patterning stable functional metallization structures on PDMS, ones with limiting feature sizes less than 5,,m, and their subsequent utilization as structures suitable for use in applications ranging from soft-lithographic patterning, non-planar electronics, and microfluidic (lab-on-a-chip, LOC) analytical systems. We demonstrate specifically that metal patterns embedded in both planar and spherically curved PDMS substrates can be used as compliant contact photomasks for conventional photolithographic processes. The non-planar photomask fabricated with this technique has the same surface shape as the substrate, and thus facilitates the registration of structures in multilevel devices. This quality was specifically tested in a model demonstration in which an array of one hundred metal oxide semiconductor field-effect transistor (MOSFET) devices was fabricated on a spherically curved Si single-crystalline lens. The most significant opportunities for the processes reported here, however, appear to reside in applications in analytical chemistry that exploit devices fabricated using the methods of soft lithography. Toward this end, we demonstrate durably bonded metal patterns on PDMS that are appropriate for use in microfluidic, microanalytical, and microelectromechanical systems. We describe a multilayer metal-electrode fabrication scheme (multilaminate metal,insulator,metal (MIM) structures that substantially enhance performance and stability) and use it to enable the construction of PDMS LOC devices using electrochemical detection. A polymer-based microelectrochemical analytical system, one incorporating an electrode array for cyclic voltammetry and a microfluidic system for the electrophoretic separation of dopamine and catechol with amperometric detection, is demonstrated. [source]

Contact-Printed Microelectromechanical Systems

Miniaturization of a Laser Doppler Blood Flow Sensor by System-in-Package Technology: Fusion of an Optical Microelectromechanical Systems Chip and Integrated Circuits

IEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, Issue 2 2010
Wataru Iwasaki Member
Abstract We have developed the first and the smallest blood flow sensor composed of integrated circuits (ICs) fused with an optical microelectromechanical systems (MEMS) chip using system-in-package (SiP) technologies for application in a healthcare monitoring system. The probe of this blood flow sensor consists of three layers, and the optical MEMS chip is stacked as the top layer. Through silicon via (TSV), vertical-cavity surface-emitting laser (VCSEL) and cavities enable wafer-level packaging of the optical MEMS chip. The other two layers consisting of ICs are highly densified by SiP technology, and the volume of the probe is miniaturized to about one-sixth of our previously reported integrated laser Doppler blood flowmeter, an MEMS blood flow sensor to which SiP technology was not applied. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source]

A method for measuring bending stresses based on electromagnetic actuation and Raman spectroscopy

JOURNAL OF RAMAN SPECTROSCOPY, Issue 2 2007
Yongfeng Ren
Abstract Bending stress and fracture strength of micromachined structures are the parameters determining the function and life span of microelectromechanical systems (MEMS) and are also indispensable data for MEMS design. This paper reports the results of a study in which a bending stress measurement method based on electromagnetic actuation and Raman spectroscopy has been examined. In this study, an eight-cantilever mass structure is chosen as the experimental object. The results have indicated that it can accurately measure the bending stresses and fracture strength. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Fully unstrained GaN on sacrificial AlN layers by nano-heteroepitaxy

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2007
K. Tonisch
Abstract Usually, the fabrication of microelectromechanical systems (MEMS) requires unstrained or tensile strained active layers on a selectively removable sacrificial layer, since compressive strain causes instabilities due to buckling effects. For group III-nitride based MEMS, AlN is a promising material for sacrificial layers since it can be epitaxially overgrown and etched selectively to GaN. However, due to the larger lattice constants GaN is growing compressively strained on AlN. Nanoheteroepitaxy opens a way to yield fully unstrained, high quality epitaxial GaN layers on nanocrystalline AlN thin film by means of a 3D strain relaxation mechanism. For this purpose sputtered nanocrystalline AlN films were overgrown with single crystalline GaN and AlGaN/GaN layers by metalorganic chemical vapor deposition. The high quality of the layers is proven by an atomically flat surface and a 2D electron gas at the interface of the AlGaN/GaN heterostructure (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]