1,721,019 research outputs found
Wet release technology for bulk-silicon resonators fabrication on silicon-on-insulator substrate
No full textStiction occurring in the release phase is a severe problem in
many MEMS devices. This phenomenon is due to capillary forces and solid–solid adhesion, which develops during drying after a wet etching process. The possibilities and the limits of the use of a solvent with low surface tension is investigated in the case of MEMS resonators fabricated on silicon-on-insulator substrate. It is shown as in this case it is possible to obtain stiction-free structures without the necessity of more expensive and complicated techniques such as supercritical drying or hydrofluoric acid (HF) vapor etching. The fabrication and design limit of this solution are also investigated
Collaborate or Perish: A Conceptual Framework for Banks and FinTechs Partnerships
Full text linkIn the Open Finance framework, collaboration of traditional incumbents (i.e., banks) with start-ups (i.e., FinTechs) is crucial for success. However, despite the frequency and relevance of such partnerships in the financial system, research in this field is rather limited, as most works address alliances regardless of the field of application. The limited number of publications related to finance shed light primarily on the motivations promoting interaction among banks and FinTech start-ups, overlooking additional aspects and players. Therefore, theaim of this work is to build a comprehensive framework allowing to properly frame alliances in the financial industry. Focusing on the Italian context, 90 public partnerships were analysed through document analysis ofpress releases. It emerges that the majority of the alliances do not involve investments in equity and attest strong participation and commitment of FinTech start-ups. On top of common knowledge, we uncovered other relevant variables to consider in this field when analysing each partnership: its direction, which depends on whether the relation resembles more an operative agreement or an industrial one; its field of interest, which details what the collaboration is about; and its addressees, identifying the targets of these alliances.These dimensions, along with the other ones in a comprehensive framework, will contribute to the enrichment of the literature, closing a relevant gap, and serve as a guide for practitioners in addressing these partnerships
Analytical model for magnified displacement stress test structures.
No full textPointer structures can be useful means to measure the
strain of a structural layer in micromachining processes 1,
2: these structures can perform an in-situ diagnosis of the
residual stress, both compressive and tensile.
Major limitations come from the reduced displacement
range that these structures can achieve: this implies a
limited sensitivity, often in the range of less than
1μm/50MPa. In order to address this problem a
magnification device has been modeled and implemented
3, that allows for larger displacement and consequent
higher sensitivity of the pointer. We propose an analytical
model of this structure under elastic regime, and compare
its results with finite element simulation
MEMS Technology for RF Passive Components
No full textIn this work a wide overview on the exploitation of MEMS technology (MicroElectroMechanical-Systems) for Radio Frequency (i.e. RF-MEMS) and telecommunication systems is provided. In the last 10-15 years MEMS technology proved to be a valuable solution for the realization of passive components for RF circuits, like variable capacitors (i.e. varactors), inductors, switches (i.e. micro-relays), as well as more complex networks, like RF filters, impedance matching tuners etc., with remarkable characteristics in terms of low-loss, high Q-factor (quality factor), and large reconfigurability. The integration within RF circuits and platforms, of passive lumped elements and networks with such prominent characteristics, would lead to a significant increase of performance and reconfigurability of the whole system (e.g. mobile handset, satellite, radar, and so on)
Study of Bulk Micromachining Corner COmpensation with Electrochemical Anisotropic Etching
No full textRealisation of Silicon Microcalorimeters with Bulk Micromachining Technology
No full textMonolithic silicon micro-calorimeters consisting of a small suspended thermal mass that houses a highly sensible thermistor have been realised with the aid of bulk micro-machining techniques. An ad hoc post process module has been developed and adapted to the already optimised thermistor process. This micro-machining module is based on wet etchin steps, two of them been specially studied to this purpose. This process is characterised by two important features: 1) aluminium passivation together with a high anisotropy; 2) surface roughness control. All solutions are based on TMAH. A potential problem withi process are unstable edges and notching effects at the base of the supporting beams. Both problems can be overcome with a proper design of the device and a proper control of the etching time
Modeling and Control of IRST MEMS microphone
No full textThe need for high quality microphones is rising in many application fields, ranging from consumer electronics to distributed environmental control. In this paper, a new MEMS microphone, is presented and its lumped parameter model derived. In the device developed at IRST-ITC, a square planar silicon membrane is suspended over a rigid, gold-plated backplate by means of four flexural springs. This assembly constitutes a capacitor with a mobile armature, which capacitance varies with the acoustic pressure. By measuring such variations of the capacitance, the information on the acoustic pressure is then obtained. However, the measured capacitance variation is not proportional to the acoustic pressure, especially in presence of large signals, and this results in a distortion, affecting the measured quantities. In this paper, we propose the use of a force re-balancing loop, counteracting the acoustic pressure, which maintains the membrane at its equilibrium position during operation. With this solution,
the re-balancing command, generated by a properly designed controller, is proportional to the acoustic pressure. Moreover, since the motion of the membrane is negligible, the non-linear effects are almost cancelled, with major benefits on the distortion, when large signals are applied to the microphone. The effectiveness of the solution proposed is demonstrated by simulation results and experiments
Fabrication of a piston-type condenser microphone with structured polysilicon diaphragm
No full textThis work focuses on the fabrication of a piston-type silicon condenser microphone. The proposed device is basically composed of a movable polysilicon diaphragm and a fixed gold backplate, making up the condenser electrodes. The movable electrode is realized by a rigid plate supported by small flexible springs. In forder to manufacture plates which are rigid and light at the same time, polysilicon membranes stiffened by vertical ribs are investigated. The fabrication technology developed for this purpose is a variation of the HEXSIL process. Both the piston and the springs are manufactured through the same polysilicon deposition, thus providing a simple process for the fabrication of the structured diaphragm. The fixed electrode is fabricated on the same chip by electroplating a thick layer of gold. The resulting process employs a combination of bulk and surface micromachining techniques. In this paper the process architecture used in the fabrication of the first prototype is presented and some related technological problems are discussed as well. Preliminary results on the functional characterization of the microphones are finally reported
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