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Electrostatic micro generators based on variable capacitors driven by proof mass motion constitute an important class of motion energy harvesters. We present an analytical approach for calculation of the variable capacitance in non-trivial harvester structures where fringing fields can not be neglected. We restrict attention to transducers consisting of metal strip electrodes on opposing dielectrics,...
This paper leads to a one-side-actuated piezoelectric membrane showing an upward deflection under forward bias. It is also shown that one-side-actuated piezoelectric membranes achieve comparable and higher deflections as common bimorph structures with similar dimensions. The piezoelectric substrate functions as complete active element, since it is both actuator and deflectable membrane.
The mechanical fatigue behavior of gold components for MEMS applications is analyzed; an experimental procedure to measure the lifetime of components under alternate loads with different mean stress conditions is presented. Dedicated devices were designed and built able to produce alternate loading on the embedded specimens; the electrostatic actuation is used as driving force. Gold microbeams are...
Dynamic behavior of oscillating perforated gold plates under the effect of squeeze film damping is analyzed by means of experimental measurements and a compact model. Thin plates built with the surface micro-machining technique and gold electroplating were designed with many different geometrical dimensions for the plate and the holes; the number of holes is also variable. Altogether, samples with...
A load cell is a transducer to convert a force into an electrical signal. Compared with widely used strain gauge type load cells, silicon-based capacitive load cell cell can offer advantages such as uniform performance over material property change and stable mechanical property in harsh conditions. Here we present a capacitive type load cell with a load sensitive silicon structure and efficient fabrication...
Due to high integration density the influence of manufacturing technologies on the system behavior has to be considered in the design process of 3D systems. Therefore, information from different physical domains has to be provided to designers. The variety of structures and physical effects requires efficient modeling approaches and simulation algorithms. In the following a modular approach which...
The paper presents the replicas for various patterns (dots, lines, prism and lens) obtained in polymethylmethacrylate (PMMA), epoxy resin and polydimethylsiloxane (PDMS) in different conditions for polymer coating. By properly understanding of the all factors affecting the process, we follow to improve the quality of the replicas and to apply the replica molding in micro/nanofabrication of the components...
Electromechanical conversion of mechanical vibration into electrical energy looks very attractive for industrial applications recently proposed and involving wireless sensors networks. A preliminary analysis of the energy scavenger configuration is proposed by investigating the performance of microsystems based on the electrostatic coupling and testing the power scavenged by a capacitive microscavenger,...
Plastic packaging is the mainstream on microelectronic packaging technology at present. As the continuous requirements for smaller but higher density products, failure and reliability issues on MEMS/MOEMS packaging because of the hygroscopic swelling mismatch stress become more and more serious. To this end, this paper presented the stress monitoring methodologies as well as the reliability tests...
Dimension uncertainty inevitably occurs in almost every fabrication of micro structure because of its small size and ununiformity of material, therefore, the dimension error is a significant factor to be considered in MEMS structure design. The unsymmetrical gaps of capacitors induced by processing are selected to analyze the effects of error on the performance of accelerometer including its sensitivity...
This study applies a novel fabrication process of molding stamper that combines anisotropic wet etching of silicon-on-insulator (SOI) wafers with electroforming to produce precision stampers. Micron-size features, such as trapezoidal grooves and prisms, can be accurately fabricated and distributed. Because the feature geometry and the distribution can be accurately realized using the proposed scheme,...
A paddle-like cantilever beam was designed and developed as a specimen to measure the mechanical behavior of thin films. This beam is in triangle shape in order to provide uniform plane strain distribution and standard clean room processing was used to prepare the sample. The residual stress measurement of thin films application for MEMS were studied with the deflections of silver, gold, and copper...
Changes in surface topography, composition, and electromechanical properties during operation of contact-mode microdevices may impact the reliability and performance. Therefore, basic understanding of the physical processes affecting adhesion, electrical characteristics, and wear behavior of polycrystalline silicon is of great importance to the design of durable and efficient microdevices with contact...
The following topics on microelectromecahnical (MEMS) devices are dealt with: mechanical simulation; assembly technologies; bioMEMS; multiphysics simulation; devices and components; micro power generation; failure analysis; NEMS; and thermal evaluation.
We report a new method of fabricating thermal bimorph actuators utilizing high permittivity ferroelectric thin films. This device is the first known thermal cantilever actuator employing barium titanate (BaTiO3) for RF applications. Compared to electrostatic actuators, this MEMS structure is designed to handle high RF transmitted power while maintaining a high capacitance ratio due to the high permittivity...
A 3D Navier-Stokes FEM solver was used to study the damping forces due to air flow in a perforated damper in translational motion normal to surfaces. Several damper topologies with square surfaces having 16 or 64 square holes were simulated. Dimensions of micromechanical devices were used and thus a slightly rarefied gas flow was considered using slip velocity boundary conditions. Incompressible and...
This paper present results of work undertaken for exploring MEMS capabilities to fabricate AC voltage references for electrical metrology and high precision instrumentation through the mechanical-electrical coupling in MEMS devices. Several first devices have been designed and fabricated using a Silicon On Insulator (SOI) Surface Micromachining process. The measured MEMS AC voltage reference values...
Various holes in through-silicon via (TSV) technologies are analyzed and realized by inductively coupled plasma (ICP) process. Using TSV technologies as grounding connections, a Ku band miniature bandpass filter is designed and fabricated. Measured results show an insertion loss of 1.9 dB and a bandwidth of 20%. The chip size is 9.6 mm times mm. Using it as interconnections for 3-dimentional millimeter-wave...
A simple model is presented to approximate the damping due to gas in vibrating MEMS squeeze-film structures at high frequencies. The model is based on the observation that at high frequencies, where the compressible force dominates (the squeeze number sigma Gt 1), the gas flows only close to the damper borders. This new compact damping model, valid for high squeeze numbers, is derived from an analytic...
The success of the microelectronic industry in scaling down the critical dimensions of integrated circuits is impressive. It is tempting to think that the same paradigm applies for Micro-ElectroMechanical-Systems (or MEMS). Smaller MEMS will potentially reduce the system dimensions and lower its cost. Furthermore, owing to the small size of the moving part, the resonant frequency and thus the response...
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