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Enhanced Percolative Properties from Controlled Filler Dispersion in Conducting Polymer Composites (CPCs)Balogun, Yunusa A. 02 November 2009 (has links)
No description available.
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Characterization of Effects of Mixed Neutron/Gamma Irradiation on NASA Glenn SiC Piezoresistive Pressure SensorsGoodenow, Debra A., B.S. 24 June 2008 (has links)
No description available.
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Dual-Use Strain Sensors for Simultaneous Strain Measurement and Acoustic Source LocationSmith, Jason Andrew 12 August 2024 (has links)
The use of metal strain gauges and ultrasonic transducers have long been studied in the field of Nondestructive Evaluation (NDE) as a part of structural health monitoring (SHM). Strain gauges use electrical resistance to monitor strains during the loading of a component. Ultrasonic transducers are piezo devices that use a crystal-like sensing element with very low excitation energy that can monitor small strains such as acoustic emissions (AEs). These types of devices have been used to locate the sources of AEs from artificial sources, such as Hsu-Nielsen pencil lead break (PLB) tests, or natural sources such as quasi-static fracture or crack propagation. This type of evaluation has significant advantages over other types of damage inspections such as liquid die penetrant, Blue Light, Eddy Current, or X-ray inspections where visual inspections, large defects, and high levels of user experience are required.
The ultrathin silicon membrane (USM) sensor developed by NanoSonic Inc. is a piezoresistive sensor, incorporating the best aspects of a conventional strain gauge and ultrasonic transducer. The sensor can measure both the strain of a component, as well as any acoustic emission that is emitted on the component. To the author's knowledge this is the only sensor capable of simultaneous measurement of these two data types. This paper presents the sensor's ability to be used for quasi-static fracture monitoring. The sensor is first compared to commercial ultrasonic transducers in an unloaded pencil lead break (PLB) test for determining the ability in measuring lamb waves for source location estimation. The NanoSonic USM sensor is further compared to commercial strain gauges and ultrasonic transducers during a PLB test under a tensile load where it is demonstrated the USM sensor yields similar measurements to both commercial sensors. The final test was a quasi-static fracture test, where the NanoSonic USM sensor was able to detect substantially lower energy AEs than the previous test and record the strain history during fracture. This duality of the USM sensor demonstrates an inherent usefulness to NDE and SHM fields. The sensor offers sensing capabilities comparable to commercially available sensors in a smaller package, with less power consumption, at a lower cost. / Master of Science / Nondestructive evaluation (NDE) is a field within structural health monitoring (SHM) that refers to determining any defects within a component that would hinder its performance without modifying its existing condition. This has historically been done by visual inspection by which experienced personnel examine the part for defects. This is inherently flawed as cracking below the surface of a component is common and would not be detected and extensive experience is required to successfully complete this task. Components in hard-to-reach places, with coatings, or that are small also prove challenges to visual inspection. Engineers have developed several new testing methods to combat these flaws. The use of acoustic emission (AE) testing allows sensors, called ultrasonic transducers, to receive and emit sounds at high frequencies to conduct the inspection. This can be done by emitting a sound which is then propagated as a wave along the surface of the component, if the wave hits a defect, it is scattered. A receiving sensor would then receive an unexpected signal, indicating that there is a problem. Furthermore, an array of these sensors can be employed to 'listen' for these surfaces waves that may be emitted during the standard operation of the components. Things like high loads, cracking, and impacts will all be able to be detected. The use of an array of sensors will allow the location of these events.
This paper will discuss a new type of sensor, an ultrathin silicon membrane (USM) sensor developed by NanoSonic Inc. This type of sensor can detect high frequencies similar to an ultrasonic transducer, as well as measure large loads that would deform the part, resulting in an event known as strain. The novelty of the NanoSonic USM sensor is its ability to monitor both pieces of information simultaneously, which is believed to be the first to do so in the field. The ability to obtain information on strain and locations of acoustic events within a component during standard operation would be a valuable prospect for the aerospace, civil, and automotive industries.
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Dresdner Beiträge zur Sensorik25 July 2017 (has links)
Seit 1996 wird von Prof. Dr.-Ing. habil. Gerald Gerlach die Buchreihe „Dresdner Beiträge zur Sensorik“ herausgegeben, in der herausragende wissenschaftliche Beiträge der Technischen Universität Dresden, insbesondere auch des Institutes für Festkörperelektronik, publiziert werden. Zu den bisher vorliegenden Bänden sind seitdem weitere Bände hinzugekommen. Das Profil des Institutes wird durch folgende Forschungsgebiete geprägt: Thermische Infrarotsensoren, Piezoresistive Sensoren auf der Basis quellfähiger Hydrogele, Ultraschalltechnik, Funktionelle Dünnschichten, Nanoptische Sensoren. Mit der Berufung von Prof. Dr.-Ing. habil. Gerald Gerlach auf den Lehrstuhl für Festkörperelektronik zum 01.01.1996 wurde das Spektrum der Forschungsarbeiten insbesondere um die Fachgebiete der Siliziumsensoren für unterschiedliche Meßgrößen und des Entwurfs komplexer Sensor- und Aktor-Systeme in der Mikrosystemtechnik erweitert. Das Zusammenwirken von Physik, Elektronik und Technologie der Mikroelektronik bei Forschung, Entwicklung und Fertigung sowie Applikation leistungsfähiger Sensoren ist Gegenstand von Lehre und Forschung des IFE. / Since 1996 the book series „Dresdner Beiträge zur Sensorik“ edited by Prof. Dr.-Ing. habil. Gerald Gerlach has been published. The aim of this series is the publication of outstanding scientific contributions of TU Dresden, especially of those compiled at the Institute for Solid-State Electronics. The Solid-State Electronics Laboratory (Institut für Festkörperelektronik - IFE) is one of 12 laboratories of the Electrical and Computer Engineering Department at Technische Universität Dresden. Together with the Semiconductor Technology and Microsystems Lab and several chairs of the Circuits and Systems and the Packaging Labs, the Solid-State Electronics Laboratory is responsible for the microelectronics specialization in the Electrical Engineering program. Research and teaching field of the Institute for Solid-State Electronics are dedicated to the interaction of physics, electronics and (microelectronics) technology in: materials research, technology, and solid state sensor operational principles, application of sensors for special measurement problems, design of sensors and sensor systems including the simulation of components as well as of complex systems, development of thin films and multilayer stacks for sensor applications, application of ultrasound for nondestructive evaluation, medical diagnostics and process measurement technology.
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Investigation of Stress Distribution and Adhesion Effects of Strain Sensitive Epoxy/MWCNT Nanocomposite FilmsBouhamed, Ayda 10 April 2019 (has links)
Carbon nanotubes (CNTs) have attracted a significant attention in a wide variety of applications due to their excellent physical and chemical properties. Specifically, CNTs reinforced polymer nanocomposites have considerable potential for the realization of highly sensitive, flexible, stable and durable strain sensors. However, the performance of polymer/CNTs strain sensors is influenced by many factors. Especially, the homogeneity of the CNTs distribution within the polymer matrix and the adhesion of nanocomposite film to the polymer substrate play a decisive role. Additionally, the electrical and piezoresistive responses of polymer/CNTs nanocomposites, as well as their response under variable environmental conditions need to be considered.
The main aim of this thesis is to develop polymer/CNTs nanocomposites for strain sensing applications. Thereby, the focus is on the development of suitable, cost-effective and simple preparation methods of polymer/CNTs-based strain sensitive nanocomposites and on the selection of suitable flexible substrate.
However, during deposition, residual stress can be formed at the interface between the film and the substrate, which leads to thin film failures. Therefore, an analytical model is developed to predict the stress distribution in the film aiming to define the suitable processing conditions for low residual stress formations. Furthermore, specific surface treatments are proposed in order to enhance the adhesion between the substrate and the thin film, which are investigated by contact angle measurement (CAM), X-rays spectroscopy (XPS)and atomic force microscopy (AFM).
Nanocomposites with up to 1 wt.% multi-walled carbon nanotubes (MWCNTs) were prepared using a simple direct mixing method. The process parameters, such as sonication time and curing time, have been determined based on several characterization techniques. Dispersions qualities were examined using morphological and topography characterizations including scanning electron microscopy (SEM) and AFM. Additionally, DC measurements were performed on the polymer/CNTs nanocomposites in order to optimize the process parameters depending on the electrical conductivity and piezoresistivity of the nanocomposite. The impact of surface treatment on the strain sensing behavior was evaluated. Furthermore, electrical and piezoresistive responses
under humidity and temperature effects were investigated.
Analytical investigations show that the residual stresses can be minimized by using low deposition temperatures and by increasing the film thickness. Comparison of surface treatment techniques demonstrates that oxygen plasma cleaning improves adhesion at the interface by enlarging the surface area and enhancing the surface wettability and the surface polarity due to the introduction of functional groups. Morphological characterizations show the good homogeneity of MWCNTs and depict the importance of optimization of sonication time for the uniform filler distribution. Furthermore, AFM analysis show that the surface roughness is reduced as sonication time is increased due to the debundling of CNTs agglomeration. However, excessive sonication time can
lead to higher roughness caused by breaking of CNTs, which get thereby the tendency to re-agglomerate.
A low percolation threshold was achieved at a CNTs concentration of 0.3 wt.% which is significantly lower than the CNT concentrations reported in literature and demonstrating the quality of dispersion process adopted. Higher sensitivity is achieved at this CNTs concentration with approximately linear piezoresistive behavior of around R 2 = 0.9904. The novel strain sensitive nanocomposites show good stability at ambient conditions and good durability under mechanical cyclic test. In addition, it is found that the sensing behavior depends greatly on the surface roughness. A high stability and linearity with good sensitivity were observed for the sensor having low surface roughness. The temperature and humidity dependency of the composite is affected by
the environmental changes. Therefore, an encapsulation of the film is required to minimize moisture absorption in addition to get better sensor recovery under mechanical load comparing to non-encapsulated film. / Kohlenstoff-Nanoröhrchen (CNTs) genießen aufgrund ihrer hervorragenden physikalischen und chemischen Eigenschaften in einer Vielzahl von Anwendungen eine große Aufmerksamkeit. Insbesondere CNT-verstärkte polymere Nanokomposite haben ein erhebliches Potenzial für die Realisierung hochempfindlicher, flexibler, stabiler und langlebiger Dehnungssensoren. Die Eigenschaften von Polymer/CNT-Dehnungssensoren werden von vielen Faktoren beeinflusst. Insbesondere die Homogenität der CNT-Verteilung innerhalb der Polymermatrix und die Haftung des Nanokompositfilms auf dem Polymersubstrat spielen eine entscheidende Rolle. Darüber hinaus müssen die elektrischen und piezoresistiven Eigenschaften von Polymer/CNTs-Nanokompositen
sowie deren Reaktion auf variable Umgebungsbedingungen berücksichtigt werden. Das Hauptziel dieser Arbeit ist die Entwicklung von Polymer/CNT-Nanokompositen für die Anwendung als Dehnungsmessstreifen. Der Fokus liegt auf der Entwicklung geeigneter, kostengünstiger und einfacher Präparationsmethoden von Polymer/CNT-basierten dehnungsempfindlichen Nanokompositen und deren Realisierung auf geeigneten flexiblen Substraten. Während der Abscheidung kann an der Grenzfläche zwischen Film und Substrat Eigenspannung entstehen, die zu Dünnschichtfehlern führt. Daher wird ein analytisches Modell zur Vorhersage der Spannungsverteilung im Film entwickelt, um die geeigneten Verarbeitungsbedingungen für geringe Eigenspannungsformationen zu definieren. Darüber hinaus werden spezifische Oberflächenbehandlungen vorgeschlagen, um die Haftung zwischen dem Substrat und dem Dünnfilm zu verbessern, die durch Kontaktwinkelmessung (CAM), Röntgenspektroskopie und Rasterkraftmikroskopie (AFM) untersucht werden. Nanokompositen mit bis zu 1 wt.% mehrwandigen Kohlenstoff-Nanoröhren (MWCNTs) wurden mit einem einfachen Direktmischverfahren hergestellt. Die Prozessparameter, wie Ultraschallzeit und Aushärtezeit, wurden auf der Grundlage verschiedener Charakterisierungstechniken bestimmt. Die Dispersionsqualitäten wurden mittels morphologischer und topographischer Charakterisierungen einschließlich Rasterelektronenmikroskopie (REM) und AFM untersucht. Zusätzlich wurden DC-Messungen an den Polymer/CNT-Nanokompositen durchgeführt, um die Prozessparameter in Abhängigkeit von der elektrischen Leitfähigkeit und der Piezoresistivität des Nanokomposits zu optimieren. Der Einfluss der Oberflächenbehandlung auf das Verhalten des Dehnungssensors wurde bewertet. Darüber hinaus wurden elektrische und piezoresistive Reaktionen unter Feuchtigkeits- und Temperatureinflüssen untersucht. Analytische Untersuchungen zeigen, dass die Eigenspannungen durch niedrige Depositionstemperaturen und eine Erhöhung der Schichtdicke minimiert werden können. Der Vergleich von Oberflächenbehandlungstechniken zeigt, dass die Sauerstoff-Plasma-Reinigung die Haftung an der Grenzfläche verbessert, in dem sie die
Oberfläche vergrößert und die Benetzbarkeit der Oberfläche sowie die Oberflächenpolarität durch die Einführung von Funktionsgruppen verbessert. Morphologische Charakterisierungen zeigen die gute Homogenität vom Epoxid /MWCNTs Nanokompositen und die Bedeutung der Optimierung der Ultraschallzeit für die gleichmäßige Füllstoffverteilung. Darüber hinaus zeigt die AFM Analyse, dass die Oberflächenrauhigkeit durch die Entbündelung der CNT-Agglomerate für eine längere Ultraschallzeit reduziert wird. Eine übermäßige Ultraschallzeit kann jedoch zu einer höheren Rauigkeit durch Brüche von CNTs führen, die dadurch zu einer erhöhten Reagglomerationsneigung führen. Ein niedriger Perkolationsschwellenwert wurde bei einer CNT-Konzentration von 0.3 wt.% erreicht, welches deutlich niedriger als die in der Literatur berichteten CNT-Konzentrationen ist. Dies belegt die hohe Qualität des vorgeschlagenen Dispersionsprozesses. Eine höhere Empfindlichkeit wird bei dieser CNT-Konzentration mit einem annähernd linearen piezoresistiven Verhalten von etwa R 2 = 0.9904 erreicht. Die neuartigen spannungsempfindlichen Nanokompositen weisen eine gute Stabilität der Umgebungsbedingungen und eine gute Haltbarkeit im mechanischen Zyklustest auf. Darüber hinaus wird festgestellt, dass das Abtastverhalten stark von der Oberflächenrauheit abhängt. Eine hohe Stabilität und Linearität bei guter Empfindlichkeit wurde für den Sensor mit geringer Oberflächenrauigkeit beobachtet. Das Verhalten des Sensors wird durch Umweltveränderungen aufgrund von Temperatur und Luftfeuchtigkeit beeinflusst. Daher ist eine Verkapselung des Films erforderlich, um die Feuchtigkeitsaufnahme zu minimieren. Die realisierte Verkapselung hat zusätzliche Vorteile in Bezug auf die Sensor Rückgewinnung unter mechanischer Belastung im Vergleich zu nicht gekapseltem Film gezeigt.
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Systèmes électromécaniques nanométriques a base de nano-fils de silicium et nanotubes de carboneMile, Ervin 03 June 2010 (has links) (PDF)
Les systèmes nano-électro-mécaniques (NEMS) sont des dispositifs de tailles nanométriques composés de structure mécaniques mobiles et de circuits électroniques. Ils intègrent des fonctions électriques et mécaniques à l'échelle nanométrique. Leurs but est de détecter une certaine quantité physique et de le convertir dans un signal électrique mesurable. Les structures mécaniques mobiles des NEMS sont principalement constituées par des nano-poutres en silicium, des nano-leviers, des nanotubes de carbone et des nano-fils. Un changement dans l'environnement entraîne un changement dans leurs propriétés mécaniques et électriques (amplitude de mouvement, la fréquence de résonance, facteur de qualité etc.). Cette variation est convertie par des transducteurs appropriés dans un signal électrique. Ces dispositifs permettent la collecte d'informations environnementales comme le changement de température, de pression, de masse et de force. Des capteurs plus performants sont réalisés grâce à leurs ultra-petites masses, hautes fréquences de résonance (10Mhz-1Ghz), grands facteurs de qualité et une faible consommation. Les NEMS permettent une large gamme d'applications potentielles. Ils sont envisagés pour être utilisé dans des applications de détection de force ou de masses ultra-petites, par exemple dans des capteurs chimiques ou biologiques. Malgré, les grands avantages offerts par les NEMS, il n'existe pas encore une technique bien établie pour détecter efficacement le signal électrique généré par le déplacement mécanique de ces nanostructures. Le défi technologique le plus important dans le fonctionnement de ces systèmes est la détection efficace du déplacement nanométrique à des fréquences élevées. L'efficacité de la transduction détermine les performances des dispositifs et fixe leurs limites. L'objectif de cette thèse est orienté sur la résolution de ce problème majeur. La recherche est spécialement conduite sur le développement d'une technique de détection à base de nano-fils pour la transduction du déplacement nano-mécanique dans un signal électrique. Les travaux présentés dans cette thèse ont été organisée autour de trois axes principaux: La première partie vise à évaluer et comparer théoriquement les différents systèmes d'actionnement et de détection de NEMS à base de nano-fils afin de choisir celle qui présente le plus grand gain de transduction et le rapport signal/fond (SBR). Cette approche est cruciale, car ces résultats vont décider la poursuite de nos recherches et les techniques à mettre en œuvre. Ce travail est la base de départ avant de passer au développement. La deuxième partie est dédiée à la fabrication de dispositifs NEMS et à la mise en œuvre d'un système d'actionnement et de détection du mouvement mécanique à des fréquences jusqu'à 100 MHz. Cette étape nous permet de continuer avec l'évaluation expérimentale de l'efficacité de transduction. La troisième partie est centrée sur la caractérisation expérimentale de l'efficacité de transduction. Les paramètres centraux qui vont être explorées sont : le gain de transduction, le rapport signal à fond, le rapport signal sur bruit (SNR), la fréquence de résonance des dispositifs, le facteur de qualité, le déplacement et la résolution ultime de masse. Ces résultats expérimentaux sont d'une grande importance car ils sont utilisés pour confirmer les attentes et valider les analyses théoriques. Enfin, ces résultats sont comparés avec ceux donnés par l'état d'art, afin de mettre en évidence le progrès et la contribution dans ce domaine.
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Synthesis of ZnO and transition metals doped ZnO nanostructures, their characterization and sensing applicationsChey, Chan Oeurn January 2014 (has links)
Nanotechnology is a technology of the design and the applications of nanoscale materials with their fundamentally new properties and functions. Nanosensor devices based on nanomaterials provide very fast response, low-cost, long-life time, easy to use for unskilled users, and provide high-efficiency. 1-D ZnO nanostructures materials have great potential applications in various sensing applications. ZnO is a wide band gap (3.37 eV at room temperature) semiconductor materials having large exciton binding energy (60 meV) and excellent chemical stability, electrical, optical, piezoelectric and pyroelectric properties. By doping the transition metals (TM) into ZnO matrix, the properties of ZnO nanostructures can be tuned and its room temperature ferromagnetic behavior can be enhanced, which provide the TM-doped ZnO nanostructures as promising candidate for optoelectronic, spintronics and high performance sensors based devices. The synthesis of ZnO and TM-doped ZnO nanostructures via the low temperature hydrothermal method is considered a promising technique due to low cost, environmental friendly, simple solution process, diverse 1-D ZnO nanostructures can be achieved, and large scale production on any type of substrate, and their properties can be controlled by the growth parameters. However, to synthesize 1-D ZnO and TM-doped ZnO nanostructures with controlled shape, structure and uniform size distribution on large area substrates with desirable properties, low cost and simple processes are of high interest and it is a big challenge at present. The main purpose of this dissertation aims to develop new techniques to synthesize 1-D ZnO and (Fe, Mn)-doped ZnO nanostructures via the hydrothermal method, to characterize and to enhance their functional properties for developing sensing devices such as biosensors for clinical diagnoses and environmental monitoring applications, piezoresistive sensors and UV photodetector. The first part of the dissertation deals with the hydrothermal synthesis of ZnO nanostructures with controlled shape, structure and uniform size distribution under different conditions and their structural characterization. The possible parameters affecting the growth which can alter the morphology, uniformity and properties of the ZnO nanostructures were investigated. Well-aligned ZnO nanorods have been fabricated for high sensitive piezoresistive sensor. The development of creatinine biosensor for clinical diagnoses purpose and the development of glucose biosensor for indirect determination of mercury ions for an inexpensive and unskilled users for environmental monitoring applications with highly sensitive, selective, stable, reproducible, interference resistant, and fast response time have been fabricated based on ZnO nanorods. The second part of the dissertation presents a new hydrothermal synthesis of (Fe, Mn)-doped-ZnO nanostructures under different preparation conditions, their properties characterization and the fabrication of piezoresistive sensors and UV photodetectors based devices were demonstrated. The solution preparation condition and growth parameters that influences on the morphology, structures and properties of the nanostructures were investigated. The fabrication of Mn-doped-ZnO NRs/PEDOT:PSS Schottky diodes used as high performance piezoresistive sensor and UV photodetector have been studied and Fe-doped ZnO NRs/FTO Schottky diode has also been fabricated for high performance of UV photodetector. Finally, a brief outlook into future challenges and relating new opportunities are presented in the last part of the dissertation.
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Novel sensor and switch applications for flexible and stretchable electronic materialsTolvanen, J. (Jarkko) 23 October 2018 (has links)
Abstract
In this thesis flexible electronics composite materials were developed and utilized in pressure sensors. Additionally, stretchable materials based on piezoresistive structures were fabricated and their feasibility for printed electronics switches and stretchable strain sensors was investigated.
In the first part of the thesis two types of composite materials were developed based on polyurethane foam with added carbon powder and on liquid crystal polymer with ceramic powder. The first developed composite was utilized in piezoresistive and capacitive hybrid sensors and the latter one for an additive manufactured piezoelectric sensor strip suitable for operation at elevated temperatures. The formable hybrid sensor achieved a maximum pressure sensitivity of 0.338 kPa-1 with response and recovery times less than 200 ms at pressures over 200 kPa and also showed a linear response. The sensor could be utilized, for example, in wearable electronics and robotics. The new type of piezoelectric material showed piezoelectric coefficients of d33 > 14 pC/N and g33 > 108 mVm/N at pressure below 10 kPa with a wide pressure sensing range up to 4.5 MPa. This was higher than that previously achieved for materials fabricated using traditional printing techniques. The piezoelectric sensor would be suitable for industrial process control at elevated temperatures.
In the second part of the thesis the stretchable materials were utilized in a new type of piezoresistive structure to fabricate one of the first stretchable switches and a machine washable self-adherable strain sensor. The developed stretchable switch could be actuated with either stretching or vibration with a minimum movement of < 2 μm. The versatile strain sensor with a tunable resistance-strain characteristic achieved the currently highest reported gauge factor (>105) at > 70% stretching. The strain sensor could be utilized for sensing human body movements and physiological signals. / Tiivistelmä
Väitöstyössä kehitettiin joustavan elektroniikan komposiittimateriaaleja, joita hyödynnettiin paineantureissa sekä käytettiin venytettäviä materiaaleja painettavan elektroniikan kytkimen ja venymäanturin valmistukseen.
Työn ensimmäisessä osassa kehitettiin kahdenlaisia komposiittimateriaaleja, joista ensimmäinen pohjautui polyuretaanivaahtoihin, joihin sisällytettiin hiilijauhetta, sekä toinen nestekidepolymeeriin, johon lisättiin keraamijauhetta. Ensimmäistä kehitettyä komposiittia hyödynnettiin pietsoresistiivisessä ja -kapasitiivisessa hybridianturissa ja jälkimmäistä lisäaine valmistettavassa pietsosähköisessä anturinauhassa, joka soveltui kohotettuihin lämpötiloihin. Muovattavalla hybridianturilla saavutettiin herkkyyden maksimiarvoksi 0.338 kPa-1, alle 200 ms vaste- ja palautumisajat yli 200 kPa paineessa ja lineaarinen vaste. Anturia voitaisiin monipuolisesti hyödyntää mm. puettavassa elektroniikassa ja robotiikassa. Uudenlaisella pietsosähköisellä materiaalilla saavutettiin pietsosähköiset kertoimet (d33 > 14 pC/N ja g33 > 108 mVm/N < 10 kPa paineessa), jotka olivat korkeammat kuin perinteisin tulostusmenetelmin valmistetuilla materiaaleilla. Pietsosähköinen anturi soveltuisi mm. teolliseen prosessivalvontaan kohotetuissa lämpötiloissa.
Toisessa osassa hyödynnettiin venytettäviä materiaaleja uudentyyppisissä pietsoresistiivisissä rakenteissa ensimmäisten venytettävän painettavan elektroniikan kytkimen sekä konepestävän itsekiinnityttävän venymäanturin valmistamiseksi. Tulokset on esitetty kahdessa julkaisussa, joista ensimmäinen keskittyi kytkimen valmistamiseen ja toimintaan sekä toinen venymäanturin toimintaan ihmiskehon liikkeen ja signaalien mittaamiseksi. Kehitettyä kytkintä voitiin aktuoida monipuolisesti esim. venytyksen tai värinän avulla alle 2 μm liikkeellä. Monipuolisella venymäanturilla saavutettiin säädettävä resistanssi-venymä suhde korkeimmalla tähän asti ilmoitettu herkkyydellä (>105) yli 70% venytyksellä. Venymäanturia voitiin hyödyntää ihmiskehon liikkeiden ja fysiologisten signaalien mittaamiseen.
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Analyse Expérimentale et Numérique des Contraintes Thermomécaniques Induites lors des Procédés Émergents de Fabrication de Puces Électroniques au moyen des Capteurs Embarqués / Experimental and Numerical Analysis of Thermomechanical Stresses Induced during the Emerging Processes of Chips Manufacturing by means of Embedded SensorsEwuame, Komi Atchou 14 June 2016 (has links)
Pour la détermination des contraintes thermomécaniques au niveau du silicium, les capteurs piézorésistifs (en rosette) composés de 4nMOS et 4pMOS ont été développés et embarqués dans des produits de la microélectronique.Les relations caractéristiques liant les grandeurs piézorésistives, électriques et mécaniques ont été établies.La détermination des grandeurs piézorésistives nécessite un test de calibration effectué ici à l’aide d’une machine de flexion quatre-points. Cette machine a été conçue et fabriquée dans le cadre de cette thèse et permet d’appliquer une contrainte uniforme uni-axiale dans l’échantillon de silicium et de déterminer ainsi les trois coefficients piézorésistifs.Les capteurs intégrés sur différentes technologies telles que CMOS65, BiCMOS55, CMOS40, BSI140 et PIC25 ont été calibrés avec cette machine.Ces capteurs MOS ont été utilisés dans les cas d’études des contraintes induites par le TSV (technologie CMOS65), par la mise en boitier avec un empilement 3D (technologie CMOS65) et un empilement 2D (technologie BiCMOS55).Les résultats donnent des composantes de contraintes (σyy, σzz) qui ne sont pas en bonne corrélation avec les résultats de simulations. Les réponses électriques des MOS orientés à 90° (direction [010]) par rapport à l’axe des x (direction [100]) sont mises en question, car le coefficient (π12) obtenu à partir de ce MOS agit directement sur les deux composantes de contraintes.D’autre part, les variations de contraintes dans la zone des capteurs, les variabilités inter-puces et inter-plaques perturbent les résultats.Intégrées dans la même structure de test de la technologie CMOS40, différents composants ont été étudiés, notamment les transistors MOS rosette, la structure bandgap et les résistances poly-Si qui ont aussi été calibrés.Une étude de la contrainte thermomécanique induite par la mise en boitier de cette technologie a révélé un fort impact sur les réponses de sortie (mobilité des MOS, tension bandgap).Par une étude de minimisation paramétrique, cet impact a été réduit en agissant sur les dimensions géométriques des constituants et les propriétés matériaux de la résine de moulage.Ces résultats montrent que les MOS en rosette peuvent être utilisés comme capteurs de contraintes mais avec une efficacité limitée. L’utilisation des résistances actives comme capteurs de contraintes est donc envisageable. Par contre, ces MOS peuvent être utilisés pour déterminer l’impact des contraintes sur le fonctionnement de la puce. / For the thermomechanical stress assessment in silicon, piezoresistive sensors (in rosette) composed of 4nMOS and 4pMOS were developed and embedded into microelectronic products.The characteristic relations between piezoresistive, electrical and mechanical quantities were established.Piezoresistive quantities were identified thanks to a four-points bending calibration machine. This machine was designed and fabricated in the frame of this PhD and enables applying a known uniform uniaxial stress into silicon sample and then calculating the three piezoresistive coefficients.The sensors embedded into different technologies such as CMOS65, BiCMOS55, CMOS40, BSI140 and PIC25 were calibrated with this machine.These MOS sensors were used for studying stresses induced by TSV (CMOS65 technology), by packaging with 3D stacking (CMOS65 technology) and 2D stacking (BiCMOS55 technology).The results give stress components (σyy, σzz) which are not in a good agreement with simulation results. Electrical responses of the MOS oriented at 90° ([010] direction with respect to the x axis ([100] direction)) are questioned because the coefficients (π12) obtained from this MOS acts directly on the two components.In addition, stress variations in sensors area, as well as inter-chips and inter-wafers variabilities disturb the results.Integrated into the same test chip of the CMOS40 technology, different structures were studied, namely the MOS transistors, the bandgap structure and the poly-Si resistances which were also calibrated.For this technology, a study of thermomechanical stress induced by packaging revealed a significant impact on the output responses (MOS mobility, bandgap voltage). Through a minimization parametric study, this impact was reduced by controlling the geometrical dimensions of components and the material properties of the moulding compound.These results show that, MOS rosettes can be used as stress sensors but with a limited efficiency. The use of active resistances as stress sensors is therefore envisaged. However, these MOS can be used to study the impact of stresses on the chip operation.
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Sensor de pressão microeletronico baseado no efeito piezoMOS / Microelectronic pressure sensor based on the piezoMOS effectGarcia, Vitor 21 February 2006 (has links)
Orientador: Fabiano Fruett / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-06T06:47:54Z (GMT). No. of bitstreams: 1
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Previous issue date: 2006 / Resumo: Apresentamos neste trabalho um sensor de pressão de baixo consumo de potência. totalmente compatível com o processo de fabricação CMOS. constituído por um amplificador operacional sensível ao estresse mecânico fabricado sobre uma membrana. O desenho do layout do amplificador é feito de forma a maximizar o efeito do estresse sobre os transistores do par de entrada e minimizar sobre o restante do circuito. O projeto da membrana. bem como a localização dos elementos sensores sobre a mesma. Foram determinados através de simulação por elementos finitos. O sensor foi fabricado utilizando o processo CMOS 0.35 IJ.m AMS disponibilizado pelo Projeto Multi-Usuário (PMU) Fapesp. A membrana do sensor foi obtida através de um processo de desbaste mecânico da pastilha de silício onde o circuito foi fabricado. Analisamos também a dependência da tensão de limiar e da mobilidade de um transistor PMOS com relação ao estresse mecânico. O sensor fabricado apresentou um consumo de potência da ordem de 3 IJ. W e uma sensibilidade de 8.9 mV/psi / Abstract: A nove I Iow power totally CMOS compatible mechanical-stress sensitive differential amplifier. which can be used as a pressure sensor. is presented. This amplifier is based on a special designed layout where the stress sensitivity of the input differential pair. is maximized and the stress effects on the second stage are minimized. Finite element simulation was used to design the membrane and to locate the element sensor on it. The sensor was fabricated in a CMOS 0.35 IJ.m AMS process supported by the Fapesp Multi -User Project. In order to make a pressure sensor without a backside bulk micro-machining process. the thickness of the die was reduced by a mechanical polishing process. This work also analised the limiar-voltage and the mobility dependence with regard to mechanical stress. The sensor power consumption amounts to 3 IJ. W and the sensitivity amounts to 8.9 m V/psi / Mestrado / Eletrônica, Microeletrônica e Optoeletrônica / Mestre em Engenharia Elétrica
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