MEMS Systems Research Articles

Micro-machined electron transparent alumina vacuum windows

We report the use of porous alumina membranes as stable electron transparent windows for atmospheric electron spectroscopy applications. This material is very brittle and under compressive stress, and therefore of limited use. We developed a method of forming these membranes being tensile, within a monolithic, stable aluminum frame, enabling handling and making it possible to mount these elements in MEMS systems. Ten micron thick membranes showed a high electron transmissivity for electron energies down to 5 kV, and their mechanical properties are close to state of the art for MEMS vacuum windows. Self-collimated channeling of electrons along the pores is proposed as an explanation for the unexpected electron transparency of these membranes.

Biocavity lasers for biomedicine

Laser technology has advanced dramatically and is an integral part of the healthcare delivery systems of today. Lasers are used in laboratory analyses of human blood samples and serve as surgical tools that kill, burn or cut tissue. Recent semiconductor microtechnology has reduced the laser size to the size of a biological cell or even a virus particle. The integration of these ultra-small lasers with biological systems makes it possible to create microelectrical mechanical systems that might revolutionize healthcare delivery.

Fluctuation Microscopy Studies of Amorphous Diamond-Like Carbon Films

Abstract Hydrogen-free amorphous diamond-like carbon films have stimulated great interest because of their useful properties, such as high hardness, chemical inertness, thermal stability, wide optical gap, and negative electron affinity[l]. Consequently, they may have various potential applications in mechanical and optical coatings, MEMS systems, chemical sensors and electronic devices. Amorphous diamond-like carbon films often contains significant amounts of four-fold or sp3 bonded carbon, in contrast to amorphous carbon films prepared by evaporation or sputtering which consist mostly of three-fold or sp2 bonded carbon. The ratio and the structure configurations of these three-fold and four-fold carbon atoms certainly decide the properties of these amorphous diamond-carbon films. Although the ratio of three-fold and four-fold carbon has been studied with Raman spectroscopy and electron-loss-energy spectroscopy, very little has been understood regarding key questions such as how the three-fold and the four-fold carbon atoms are integrated in the film, and what structures those three-fold carbon atoms take.

Quantum–enhanced information processing

Restricted accessMoreSectionsView PDF ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmail Cite this article Mosca M., Jozsa R., Steane A. and Ekert A. 2000Quantum–enhanced information processingPhil. Trans. R. Soc. A.358261–279http://doi.org/10.1098/rsta.2000.0531SectionRestricted accessQuantum–enhanced information processing M. Mosca M. Mosca Centre for Quantum Computation, Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, UK Mathematical Institute, University of Oxford, 24–29 St Giles', Oxford OX1 3LB, UK Google Scholar Find this author on PubMed Search for more papers by this author , R. Jozsa R. Jozsa Department of Computer Science, University of Bristol, Woodland Road, Bristol BS8 1UB, UK Google Scholar Find this author on PubMed Search for more papers by this author , A. Steane A. Steane Centre for Quantum Computation, Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, UK Google Scholar Find this author on PubMed Search for more papers by this author and A. Ekert A. Ekert Centre for Quantum Computation, Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, UK Google Scholar Find this author on PubMed Search for more papers by this author M. Mosca M. Mosca Centre for Quantum Computation, Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, UK Mathematical Institute, University of Oxford, 24–29 St Giles', Oxford OX1 3LB, UK Google Scholar Find this author on PubMed Search for more papers by this author , R. Jozsa R. Jozsa Department of Computer Science, University of Bristol, Woodland Road, Bristol BS8 1UB, UK Google Scholar Find this author on PubMed Search for more papers by this author , A. Steane A. Steane Centre for Quantum Computation, Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, UK Google Scholar Find this author on PubMed Search for more papers by this author and A. Ekert A. Ekert Centre for Quantum Computation, Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, UK Google Scholar Find this author on PubMed Search for more papers by this author Published:15 January 2000https://doi.org/10.1098/rsta.2000.0531AbstractInformation is stored, transmitted and processed always by physical means. Thus the concept of information and computation can be properly formulated only in the context of a physical theory and the study of information processing requires experimentation . It is clear that if computers are to become much smaller in the future, their description must be given by quantum mechanics. Somewhat more surprising is the fact that quantum information processing can be qualitatively different and much more powerful than its classical analogue. In the following we will explain why. Previous ArticleNext Article VIEW FULL TEXT DOWNLOAD PDF FiguresRelatedReferencesDetailsCited by Lyshevski S (2013) Nano and molecular technologies in microelectronics, MEMS and electronic systems 2013 IEEE XXXIII International Scientific Conference on Electronics and Nanotechnology (ELNANO 2013), 10.1109/ELNANO.2013.6552070, 978-1-4673-4672-6, (38-42) Lyshevski S (2012) Hardware, software and algorithmic solutions for quantum data processing 2012 IEEE 12th International Conference on Nanotechnology (IEEE-NANO), 10.1109/NANO.2012.6322135, 978-1-4673-2200-3, (1-6) Lyshevski S (2012) Molecular and Biomolecular Processing Handbook of Nanoscience, Engineering, and Technology, Third Edition, 10.1201/b11930-10, (125-178), Online publication date: 15-Jun-2012. Lyshevski S (2011) Quantum processing: Feasibility studies and solutions 2011 IEEE 11th International Conference on Nanotechnology (IEEE-NANO), 10.1109/NANO.2011.6144384, 978-1-4577-1516-7, (1527-1532) Lyshevski S Three-dimensional nanobioelectronics: towards implementation of quantum information theory and quantum computing 5th IEEE Conference on Nanotechnology, 2005., 10.1109/NANO.2005.1500733, 0-7803-9199-3, (372-374) Lyshevski S and Renz T Microtubules and neuronal nanobioclectronics 4th IEEE Conference on Nanotechnology, 2004., 10.1109/NANO.2004.1392357, 0-7803-8536-5, (379-381) Thompson J, Cornish S and Cassettari D (2003) Recent progress in Bose-Einstein condensation experiments, Philosophical Transactions of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences, 361:1813, (2699-2713), Online publication date: 15-Dec-2003. Lyshevski S Nanotechnology, quantum information theory and quantum computing 2002 2nd IEEE Conference on Nanotechnology, 10.1109/NANO.2002.1032253, 0-7803-7538-6, (309-314) Gillmor S, Rugheimer P and Lagally M (2002) Computation with DNA on surfaces, Surface Science, 10.1016/S0039-6028(01)01524-2, 500:1-3, (699-721), Online publication date: 1-Mar-2002. Walgate J, Short A, Hardy L and Vedral V (2000) Local Distinguishability of Multipartite Orthogonal Quantum States, Physical Review Letters, 10.1103/PhysRevLett.85.4972, 85:23, (4972-4975) This Issue15 January 2000Volume 358Issue 1765Theme Issue ‘Science into the next millennium: young scientists give their visions of the future I. Astronomy and Earth sciences’ compiled by J. M. T. Thompson Article InformationDOI:https://doi.org/10.1098/rsta.2000.0531Published by:Royal SocietyPrint ISSN:1364-503XOnline ISSN:1471-2962History: Published online15/01/2000Published in print15/01/2000 License: Citations and impact KeywordsTeleportationQuantum error correctionQuantum algorithmsQuantum computationQuantum communicationQuantum cryptography

A MEMS electrostatic particle transportation system

We demonstrate here an electrostatic MEMS system capable of transporting particles 5–10 μm in diameter in air. This system consists of three-phase electrode arrays covered by insulators. Extensive testing of this system has been done using a variety of insulation materials (silicon nitride, photoresist and Teflon), thickness (0–12 μm), particle sizes (1–10 μm), particle materials (metal, glass, polystyrene, spores, etc.), waveforms, frequencies and voltages. Although previous literatures [D.W. Cooper, H.L. Wolfe, J.T.C. Yeh, R.J. Miller, Surface cleaning by electrostatic removal of particles, Aerosol Science and Technology 13 (1990) 116–123; V.J. Novick, C.R. Hummer, P.F. Dunn, Minimum electric field requirements for removing powder layers from a conductive surface, Journal of Applied Physics 65 (1989) 3242–3247] claimed it is impractical to electrostatically transport particles with sizes 5–10 μm due to complex surface forces, this effort actually shows it is feasible (as high as 90% efficiency) using the optimal combination of insulation thickness, electrode geometry and insulation material. Moreover, we suggest a qualitative theory for our particle transportation system which is consistent with our data and finite-element electrostatic simulations.

A new flip-chip bonding technique using micromachined conductive polymer bumps

Using micromachining techniques with thick photoresists, a new conductive polymer flip-chip bonding technique that achieves both a low processing temperature and a high bumping alignment resolution has been developed in this work. By the use of UV-based photolithography with thick photoresists, molds for the flip-chip bumps have been patterned, filled with conductive polymers, and then removed, leaving molded conductive polymer bumps. After flip-chip bonding with the bumps, the contact resistances measured for 25 /spl mu/m-high bumps with 300 /spl mu/m/spl times/300 /spl mu/m area and 400 /spl mu/m/spl times/400 /spl mu/m area were 35 m/spl Omega/ and 12 m/spl Omega/ respectively. The conductive polymer flip-chip bonding technique developed in this work shows a very low contact resistance, simple processing steps, a high bumping alignment resolution (</spl plusmn/5 /spl mu/m), and a lower bonding temperature (/spl sim/170/spl deg/C). This new bonding technique has high potential to replace conventional flip-chip bonding technique for sensor and actuator systems, bio/chemical /spl mu/-TAS, optical MEMS, OE-MCM's, and electronic system applications.

Properties of Low Residual Stress Silicon Oxynitrides Used as a Sacrificial Layer

AbstractLow residual stress silicon oxynitride thin films are investigated for use as a replacement for silicon dioxide (SiO2) as sacrificial layer in surface micromachined microelectrical-mechanical systems (MEMS). It is observed that the level of residual stress in oxynitrides is a function of the nitrogen content in the film. MEMS film stacks are prepared using both SiO2 and oxynitride sacrificial layers. Wafer bow measurements indicate that wafers processed with oxynitride release layers are significantly flatter. Polycrystalline Si (poly-Si) cantilevers fabricated under the same conditions are observed to be flatter when processed with oxynitride rather than SiO2 sacrificial layers. These results are attributed to the lower post-processing residual stress of oxynitride compared to SiO2.

Feedback control of the auditory periphery: Anti-masking effects of middle ear muscles vs. olivocochlear efferents

Both MEM and MOC systems are sound-evoked reflexes to the auditory periphery which can be elicited by sound in either ear. Both MEM and MOC systems can increase thresholds in the auditory periphery: the MEM system acts by stiffening the ossicular chain, the MOC system by decreasing outer hair cell amplification of sound-induced motion in the inner ear. MEM-induced attenuations are largest for low frequency stimuli, MOC-induced attenuations are largest for mid- to high-frequency sounds. Both MEM and MOC systems can have anti-masking effects. The MEM reflex can decrease the masking of high-frequency signals by low-frequency noise (i.e., the upward spread of masking). The MOC reflex is complementary in that it minimizes masking of high-frequency transient signals by high-frequency continuous noise. MEM anti-masking arises by reducing suppressive masking and can improve masked thresholds at high frequencies. MOC anti-masking arises by counteracting excitatory masking. It does not improve masked thresholds, but can improve the detectability of small suprathreshold intensity increments. Anti-masking effects of both MEM and MOC systems should be reduced in cases of sensorineural hearing loss.

Comparison of Device Performance Fabricated on Thick So and Bulk Wafers

AbstractWe have investigated the surface quality of thick 10μm Silicon-On-Insulator (SOI) wafers by comparing CMOS device performance and reliability of SOI wafers with those of bulk wafers. Large scale CMOS circuits, microcontrollers with 12Kbyte ROM and 512byte EEPROM, were fabricated on thick SOI wafers and on bulk wafers, and device performance and reliability were evaluated by means of functional tests and acceleration tests. A significant difference was observed only in the ROM bit-map failure analysis in the functional tests, in which the number of single bit failures (defined as a chain of up to 4 adjacent bit failures) was more evident on ROM fabricated on the thick SOI than that fabricated on bulk wafers. The result indicates that the crystal defects introduced by the initial oxygen concentration and excess film stress of the SiO interlayer may cause single bit failures. The SOI wafers were prepared by Direct Wafer Bonding 2(DWB) and a mechanical polishing technique to form a 10μm active silicon layer and a 625μm silicon substrate, which sandwiches a 0.25μm SiO2 interlayer. Thick SOI wafers such as these are becoming a promising material for one-chip integration of CMOS devices and Micro Electrical Mechanical System (MEMS) devices.

Reactive ion etching for microelectrical mechanical system fabrication

The suitability of reactive ion etching for the fabrication of microelectro mechanical systems (MEMS) has been evaluated by characterizing the change of lateral dimensions versus depth in etching deep structures in silicon. Fluorine, chlorine, and bromine containing gases have provided the basis for this investigation. A conventional planar RIE (reactive ion etching) reactor has been used, in some cases with magnetic field enhancement or an inductive coupled plasma source and low substrate temperature. For RIE based on Cl2 or Cl2/HBr plasma a slightly ‘‘positive’’ (top wider than bottom) slope is achieved when etching structures with a depth of several 10 μm, whereas a ‘‘negative’’ slope is obtained when etching with an SF6 /CCl2F2-based plasma. A pattern transfer with vertical walls is obtained for RIE based on SF6 (with O2 added) when maintaining the substrate at low temperature (≊−70 °C). Further optimization of plasma chemistries and RIE procedures should result in runouts on the order of 0.1/100 μm depth in Si as well as in organic materials.

The positive "vocal fremitus" in malignant breast tumors in color MEM ultrasound imaging--an exciting artifact in confirming the diagnosis?

In the experimental phase of application of a new Non-Doppler technology (MEM system, Acoustic Imaging, Phoenix; Dornier Medizintechnik) we observed, that in patients, who spoke during colour imaging of a breast tumour, artifacts appeared in or around the lesion: the colour artifacts were seen regularly inside the tumour in cases of malignancies, and exactly surrounding benign tumours. Postoperative histological findings served as an objective criterion of classification/differentiation. To examine this phenomenon, we performed a study in 71 patients. These women with a sonographically detectable tumour (37 malignant, 34 benign) were examined on the day before surgery. We observed, that if patients uttered the number "99" with a relatively low voice or alternatively hummed a deep sound, the artifacts could be regularly visualized. In 66/71 patients (93%) status evaluation by artifact generation due to vocal fremitus examination was correct. In 3 patients the tumour was erroneously described as malignant, histology showing a proliferative mastopathy. In 2 cases the tumour was classified as benign, whereas histology revealed a malignancy, in both patients a large ductal-invasive carcinoma (> 3 cm). This phenomena could, however, not be reproduced with other colour techniques. A possible explanation is: Thoracic vibrations during speech can be registered by the MEM technique. These vibrations are not perpetuated into the benign lesion characterised by a displacing growth, due to which the vibrations are "barred off" at the borders of the tumour. Infiltrating growth typical of a malignancy causes transmission of these vibrations into the center of the tumour.(ABSTRACT TRUNCATED AT 250 WORDS)

SMEOS 2011 (Sensors, Mems and Electro-Optic Systems)

This special issue of the SAIEE Africa Research Journal is devoted to selected papers from the SMEOS 2011 (Sensors, MEMS and Electro-Optic Systems) Conference which was held in Berg-en-Dal, Kruger National Park, South Africa from 19 to 21 September 2011. The aim of SMEOS 2011 was to establish a forum for academia, research institutions and industry working in the field of sensors, MEMS and electro-optical systems, to share their relevant research and development ideas. Each paper presented at the conference was double-blind reviewed by at least two reviewers. Reviewers could recommend a reviewed paper to the technical chair for publication in this special issue, and a total of eleven papers eventually passed this review process.