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En las últimas dos décadas, han surgido diferentes tecnologías acústicas para aplicaciones biosensoras como alternativas a tecnologías de detección bien establecidas ¿acústicas o ópticas¿ como son la Microbalanza de Cuarzo (QCM, por sus siglas en inglés) y la Resonancia de Plasmón de Superficie (SPR, de sus siglas en inglés). En la primera parte de este documento se revisan dichas tecnologías alternativas para aplicaciones en medio líquido. Como resultado de esta revisión, se determina que los dispositivos de onda acústica superficial Love (LW, de sus siglas en inglés) son los más prometedores y viables para conseguir el principal objetivo de esta Tesis, que es establecer una comparativa en las mismas condiciones entre inmnosensores desarrollados con la tecnología seleccionada en esta tesis y los inmunosensores desarrollados con QCMs de Alta Frecuencia Fundamental (HFF-QCM, por sus siglas en inglés). Después de esta revisión se presenta el estado del arte de los dispositivos LW en su aplicación como biosensores, así como una discusión de las tendencias y retos actuales de este tipo de sensores. Posteriormente se reúne la información más actualizada sobre aspectos de diseño, principios de operación y modelado de estos sensores. Algunos aspectos de diseño son estudiados y probados para establecer el diseño final de los dispositivos LW. Previamente a su fabricación, también se realizan simulaciones para modelar el comportamiento del dispositivo elegido previamente a su fabricación. Posteriormente, se describe la fabricación del dispositivo así como la celda de flujo diseñada para trabajar con el dispositivo en medios líquidos. Adicionalmente, un sistema electrónico de caracterización, previamente validado para sensores QCM, se adapta para sensores LW. Como resultados, se valida el sistema electrónico para caracterizar los sensores LW fabricados y montados en la celda de flujo y, finalmente, se desarrolla un inmunosensor para la detección del pesticida carbaril que se compara con otras tecnologías inmunosensoras. / In the last two decades, different acoustic technologies for biosensors applications have emerged as promising alternatives to other better established detection technologies ¿ acoustic or optic ones- such as traditional Quartz Crystal Microbalance (QCM) and Surface Plasmon Resonance (SPR). The alternative acoustic technologies for in liquid measurements are reviewed in this manuscript. Surface Acoustic Wave (SAW) Love Mode or Love Wave (LW) sensors are determined to be the most promising and viable option to work with for achieving the main aim of this Thesis. Such aim is the development of a LW immunosensor for its comparison with the same application based on High Fundamental Frequency-QCM (HFF-QCM) sensors and under the same conditions. Consequently, the state-of-the-art of LW devices for biosensing is provided and a discussion about the current trends and future challenges of these sensors is presented. In order to start working with suitable LW devices, upto- date information regarding the design aspects, operation principles and modeling of such devices is gathered. Some design aspects are explored and tested to establish the design of the final LW device. Different simulations for modeling the chosen device behavior are carried out before its fabrication. Later, the device fabrication is described. Next, to start working with the fabricated device in liquid media, a flow cell is designed and implemented. In addition, an electronic characterization system, previously validated for QCM sensors, is adapted and tested for the fabricated LW device. As results, the adapted electronic characterization system is validated for LW devices mounted in the fabricated flow cell and, finally, a LW-based immunosensor for the determination of carbaryl pesticide was developed and compared with other immunosensor technologies. / Rocha Gaso, MI. (2013). Analysis, implementation and validation of a Love mode surface acoustic wave device for its application as sensor of biological processes in liquid media [Tesis doctoral]. Editorial Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/32492

Ces travaux ont donc visé le développement d’une plateforme complète de détection de gaz pour environnement sévère haute température. Cette plateforme intègre un dispositif à ondes acoustiques de surface sur substrat Langasite, une résistance chauffante, une couche sensible inorganique nanostructurée et est placée dans une enceinte hermétique. Des températures de l’ordre de 450°C ont été atteintes et des tests de cyclages ont démontré un fonctionnement en accord avec les modèles théoriques et une reproductibilité des mesures. Des tests de détection de composés organiques volatils (éthanol et toluène) ont mis en avant des seuils de détection de l'ordre de quelques ppm. / Measuring pollutants concentrations in gas and vapors emissions are important environmental issues. This work presents a stand-alone portable device for high temperature assessment. The system includes a Langasite (LGS) acoustic sensor, a ceramic heater and a platform with RF connections for remote in-situ measurements. The packaging consists in a hermetic stainless steel cell which enables safe gas detection. In situ temperature measurements have been achieved and the thermal behavior was successfully investigated in the temperature range 25-450°C. The designed cell highlights good agreement with theoretical models and reproducibility of the measures. Volatile organic compounds exposures have been investigated and promising ppm level detections have been obtained.

Diese Arbeit befaßt sich mit der SAW-STM-Methode, einer Abwandlung der Rastertunnelmikroskopie (engl. scanning tunneling microscopy) zur hochauflösenden Abbildung akustischer Oberflächenwellen (engl. surface acoustic wave). Das Meßprinzip des SAW-STM beruht auf der Modulation des Tunnelabstandes und der hieraus resultierenden Modulation des Tunnelstroms durch die oszillatorische Bewegung der Probenoberfläche. Zur einfacheren Signaldetektion wird ein Heterodyn-Verfahren verwendet, das über eine zusätzliche Modulation der Tunnelspannung das SAW-STM Signal in den kHz-Frequenzbereich verschiebt. Dieses trägt die komplette Information über die Amplitude und die Phase der Tunnelabstandsmodulation. Im Rahmen dieser Arbeit wird die Abhängigkeit des SAW-STM Signals von den experimentellen Paramtern und von der Topographie der Probe theoretisch beschrieben und experimentell untersucht. Dies führt zu einer kalibrierten Vermessung der oszillatorischen Bewegungsbahn der SAW-tragenden Probenoberfläche. Das untersuchte Materialsystem ist ein 40 nm dicker Goldfilm auf einem LiNbO3-Substrat im Y-Schnitt, das eine Welle vom Rayleigh-Typ in Z-Richtung trägt. Indem ein SAW-STM entwickelt wird, das im Ultrahochvakuum (UHV) arbeitet, wird die SAW-STM Methode hinsichtlich des Spektrums untersuchbarer reaktiver Materialien und hinsichtlich der Signalstabilität. Es wird der Umbau eines kommerziellen Rastertunnelmikroskops zum SAW-STM beschrieben. Zu diesem Zweck wird eine Probenhalterung konstruiert, die den Transfer der Probe zwischen der Bedampfungseinrichtung und dem STM ohne Belüftung der Kammer erlaubt. Gleichzeitig stellt sie automatisch die fünf notwendigen elektrischen Kontakte zum Probenchip her, wenn die Probenhalterung in das STM gesetzt wird. Weiterhin werden die Konstruktion eines UHV-tauglichen Sytems von Hochfrequenz-Signalleitungen und der Bedampfungseinrichtung zur in-situ Probenpräparation beschrieben. Mit diesem UHV-SAW-STM können SAWs einer Amplitude im Bereich von 0.001 Å bis 1 Å angeregt und detektiert werden. Die maximale Frequenz, die eine im UHV-SAW-STM nachweisbare SAW haben kann, beträgt mindestens 360 MHz. Weiterhin wird das in LabVIEW geschriebenen Softwarepacket zur Auswertung der SAW-STM-Daten vorgestellt. Um die SAW-STM-Methode auf ein sicheres Fundament zu stellen, wurde erstmals systematisch die Abhängigkeit des SAW-STM-Signals von den Meßparametern experimentell untersucht. Die im Rahmen dieser Arbeit entwickelte Theorie des SAW-STM-Signals beschreibt die experimenell gefundenen Abhängigkeiten hinreichend gut. Zentraler Punkt dieser Theorie ist dabei die Berücksichtigung der Abstandsregelung des STM, die im Constant-Current-Modus die Spitzenposition so regelt, daß der mittlere Tunnelstrom konstant ist. Der Vergleich der gemessenen und der theoretischen Abhängigkeit der Signalamplitude von der Amplitude der Modulation des Tunnelabstandes ermöglicht dabei die kalibrierte Messung der Amplitude der vertikale Auslenkung der Rayleighwelle. Scans der SAW-STM-Methode liefern Bilder der Topographie sowie der Amplitude und der Phase des SAW-STM-Signals. Mit der Theorie des SAW-STM-Signal der korrugierten Probenoberfläche werden aus der gemessenen Topographie simulierte Amplituden- und Phasebilder erstellt und mit den gemessenen Bildern verglichen. Während die Übereinstimmung mit den gemessenen Amplitudenbildern nur qualitativer Art ist, erlaubt der quantitative Vergleich zwischen simulierten und gemessenen Phasenbildern die Bestimmung der Exzentrizität der Oszillationsellipse. Zusammen mit der oben erläuterten Messung der vertikalen Auslenkungsamplitude ist somit in dieser Arbeit die Oszillationsellipse der Rayleighwelle vollständig ausgemessen. / This thesis deals with the SAW-STM method, which is a technique based on scanning tunneling microscopy (STM) for the high-resolution mapping of surface acoustic waves (SAW). The measurement principle of the SAW-STM utilizes the modulation of the tunneling distance and the resulting modulation of the tunneling current due to the mechanic oscillation of the sample surface. To facilitate signal detection a heterodyn technique is employed which shifts the measured signal into the kHz-range by adding modulation to the tunneling voltage. The signal contains the entire information about the amplitude and the phase of the SAW-induced tunneling distance modulation. Experiments are presented to investigate the dependence of the signal amplitude on the experimental parameters and on the sample topography. This data is compared to a theory developed to describe the SAW-STM signal, leading to a calibrated measurement of the trajectory of the sample surface which carries the wave. The sample we investigated was a 40 nm gold film deposited on a LiNbO3 substrate in the Y-cut, deformed by a Rayleigh-type wave in the z-direction. To increase signal stability and to extend the range of reactive sample materials we constructed a SAW-STM operating in the ultra-high-vacuum (UHV). In this thesis the conversion of a commercial STM to a SAW-STM is described. A sample holder is constructed, which allows the transfer of the sample between the evaporation stage and the STM without venting the UHV chamber. It provides a contact spring mechanism for the automatical electric contactation of the sample chip, when the sample holder is inserted into the STM. Moreover, we installed a UHV-compatible wiring system for SAW-excitation and for signal detecting and an evaporation stage for in-situ sample preparation. We demonstrate that the UHV-SAW-STM is capable of exiting and detecting surface acoustic waves with an amplitude in the range 0.001 Å to 1 Å. The maximal frequency of SAW which can be studied with the UHV-SAW-STM is found to be at least 360 MHz. For the analysis of SAW-STM data a LabVIEW software package was implemented. To put the SAW-STM technique on a strong basis, we systematically studies the dependence of the SAW-STM signal on the various measurement parameters. The theory of the SAW-STM signal developed in this work is in good agreement with this experimental data. In this theory, we take into account that the STM is operated in the constant-current mode, i.e. the tip position is controlled to keep the average tunneling current constant. The comparison of the measured and the simulated dependence of the signal amplitude on the amplitude of the tunneling distance modulation allows the calibrated measurement of the vertical displacement amplitude of the Rayleigh wave. SAW-STM scans yield images of the topography and of the amplitude and the phase of the SAW-STM signal. Employing the theory of the SAW-STM signal on the corrugated surface, we simulated amplitude and phase imaged based on the measured topography. The agreement between simulated and measured amplitude images is only qualitative. In contrast, the comparison of simulated and measured phase images allows the determination of the excentricity of the oscillation ellipse. Having determined this excentricity and the vertical displacement amplitude of the Rayleigh wave, we have gaind complete knowledge about the geometry of the Rayleigh wave oscillation ellipse.

We studied the possibility of achieving an order of magnitude reduction in the energy dissipation needed to write bits in perpendicular magnetic tunnel junctions (p-MTJs) by simulating the magnetization dynamics under a combination of resonant surface acoustic waves (r-SAW) and spin-transfer-torque (STT). The magnetization dynamics were simulated using the Landau-Lifshitz-Gilbert equation under macrospin assumption with the inclusion of thermal noise. We studied such r-SAW assisted STT switching of nanomagnets for both in-plane elliptical and circular perpendicular magnetic anisotropy (PMA) nanomagnets and show that while thermal noise affects switching probability in in-plane nanomagnets, the PMA nanomagnets are relatively robust to the effect of thermal noise. In PMA nanomagnets, the resonant magnetization dynamics builds over few 10s of cycles of SAW application that drives the magnetization to precess in a cone with a deflection of ~45⁰ from the perpendicular direction. This reduces the STT current density required to switch the magnetization direction without increasing the STT application time or degrading the switching probability in the presence of room temperature thermal noise. This could lead to a pathway to achieve energy efficient switching of spin-transfer-torque random access memory (STT-RAM) based on p-MTJs whose lateral dimensions can be scaled aggressively despite using materials with low magnetostriction by employing resonant excitation to drive the magnetization away from the easy axis before applying spin torque to achieve a complete reversal.

Lorsque des ondes acoustiques de surface rayonnent dans des fluides, elles provoquent deux effets non linéaires : la pression de radiation et le streaming acoustique. Ces deux effets ont trouvé un grand nombre d’applications pour la microfluidique digitale, la manipulation sans contact et le tri cellulaire. Néanmoins, ces systèmes se heurtent à deux limites. D’une part, chaque application requiert une onde acoustique spécifique : il n’existe pas de dispositif multifonction à ce jour. D’autre part, l’exploration des fonctionnalités offertes par les ondes de surface les plus simples (ondes planes, ondes focalisées) n’a pas permis de réaliser des pinces sélectives permettant de manipuler individuellement des particules ou cellules indépendamment de leurs voisines.Dans une première partie de la thèse, nous développons deux méthodologies pour synthétiser des champs complexes d’ondes de surface. La première méthode utilise un réseau de 32 peignes interdigités contrôlé par la technique du filtre inverse pour générer des champs sur demande. La seconde résout un problème inverse afin de concevoir un transducteur holographique générant spécifiquement le champ demandé. Dans la seconde partie de la thèse, nous utilisons le filtre inverse pour (i) réaliser un laboratoire sur puce multifonction et (ii) étudier le potentiel d’ondes de surface particulières appelées ondes de surface tourbillonnaires. Ces ondes permettent une manipulation sélective et sans contact d’objets microscopiques. Nous terminons la thèse en équipant un microscope d’un transducteur holographique de vortex acoustiques afin de réaliser une manipulation sélective et sans contact de cellules. / When surface acoustic waves radiate in nearby fluids, they trigger two nonlinear effects: acoustic radiation pressure and acoustic streaming. These two effects find numerous applications for digital microfluidics, contactless manipulation and biological cell sorting. Nonetheless, these systems face two limitations. On the one hand, each application requires a specific acoustic wave: there is no multifunction device so far. On the other hand, search for functionalities offered by simple surface acoustic waves (plane and focused waves) has failed to provide a selective tweezers able to manipulate individual particles or cells independently of their neighbors. In the first part of this thesis, we develop two methods to synthesize complex surface acoustic wave fields. The first one employs an array of 32 interdigitated transducers controlled by the inverse filter to generate arbitrary fields on demand. The second method solves an inverse problem to design a holographic transducer to generate a predefined field. In the second part of the thesis, we use the inverse filter to (i) implement a multifunction lab on a chip and (ii) investigate the potentialities of a special type of surface acoustic waves called swirling surface waves. These waves enable a selective and contactless manipulation of microscopic objects. We conclude the thesis by integrating a holographic acoustical vortex transducer on a microscope in order to selectively manipulate biological cells without contact.

Higher frequencies in the MHz and GHz range and the increasing miniaturization lead to a higher load of the SAW (surface acoustic wave) metallizations. This higher SAW load and the intrinsic stresses result in a stress induced material transport, called acoustomigration. These microstructural changes can destroy the characteristic of the SAW device. Different Al based material combinations were investigated by different authors to improve the reliability of the metallizations and to delay the cost-intensive change to Cu based metallizations. The Cu based metallizations with TaSiN diffusion barriers were also investigated in this work. The barrier layers are necessary to impede the oxygen diffusion into the Cu layer and the Cu diffusion into the piezoelectric substrate. Also in this work the analytical TEM were used as a tool to investigate these microstructural changes in the SAW electrodes. Chemical changes in the metallizations were analysed by EDXS and EELS. The locally high resolved stress measurement in metallizations is a challenge for the future. The CBED (convergent beam electron diffraction) technique has shown the best resolution, however, it can only be applied to TEM lamellas. The aim of this work was to measure the stress within the SAW metallizations by using the CBED method. With it, we could correlate the microstructural changes with the causing stresses within the metallizations. To qualify the CBED method the thermal expansion of Al and Cu single crystals was measured by using a new model for thin TEM lamallas.

Diese Dissertation beschäftigt sich mit der Entwicklung eines neuartigen Konzepts für Herstellung und Handhabung von Mikrofluidiksystemen auf der Basis akustischer Oberflächenwellen (SAW) sowie der Nutzung dieses Konzepts zur Fertigung anwendungsrelevanter Teststrukturen. Schwerpunkte sind dabei unter anderem eine hohe Leistungsbeständigkeit und Lebensdauer der Chipbauelemente und eine hohe technologische Flexibilität bezüglich Herstellung und Einsatz. Ausgehend von einer modularen Betrachtungsweise der Bauelemente wurden vielseitig einsetzbare, elektrisch-optimierte Interdigitalwandler entworfen, verschiedene Herstellungsvarianten für vergrabene Interdigitalwandler hoher Leistungsbeständigkeit auf piezoelektrischen Lithiumniobat-Substraten entwickelt und experimentell verifiziert, ein Sputterverfahren für amorphe SiO2-Dünnschichten hoher Qualität optimiert und eine Federstiftkontakt-Halterung entworfen. Durch Kombination dieser Technologien wurden SAW-Bauelemente für die mikrofluidische Aktorik mit hoher Performance und Reproduzierbarkeit entworfen, charakterisiert und beispielhaft für das elektroakustische Zerstäuben von Fluiden und das Mischen in Mikrokanälen eingesetzt.

Orientador: Jacobus W. Swart / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-04T18:27:49Z (GMT). No. of bitstreams: 1 Alcantara_GlaucioPedrode_M.pdf: 1079087 bytes, checksum: afc69d32771f7a3060b934cb3fcabca4 (MD5) Previous issue date: 2005 / Resumo: Este trabalho de dissertação apresenta o estudo e projeto dos elementos que compõem um sensor de gases baseado na tecnologia de Onda Acústica de Superfície (SAW), tais como, o oscilador colpitts SAW e um ressonador SAW de uma porta, os quais estão na malha de realimentação de um amplificador. Foi realizado também a deposição de diferentes espessuras de filme fino de TiO2 sobre o sensor, a fim de se estudar o efeito da atenuação da SAW na fronteira entre o cristal e o filme. É mostrado que atenuação da SAW acontece no filme na fina camada de aproximadamente 500 angstroms de espessura. A dependência de espessura com a mudança de freqüência e com fator Q do oscilador SAW e ressonador são apresentados, bem como a ssensitividade de massa do ressonador SAW para o filme de TiO2. Um modelo de oscilador SAW usando 2 caminhos acústicos, de melhor sensitividade que aquele de modo simples, foi estudado e proposto / Abstract: This thesis presents the study and design of the elements which compose a gas sensor based on Surface Acoustic Wave technology, such as, SAW Colpitts oscillator and the SAW one-port resonator that are presents in the feedback loop of an amplifier. It was done deposition of TiO2 thin film different thickness on the sensor, in order to study the effect of SAW attenuation on the border between the crystal and the film. It is shown that SAW attenuation takes place in the film in thin layer of about 500 angstroms thickness. Thickness dependence of frequency shift and Q-factor of SAW oscillator and resonator, as well as, the mass sensitivity of SAW resonator to TiO2 film are presented. The model of SAW oscillator which uses two acoustic paths, has been studied and proposed. / Mestrado / Mestre em Engenharia Elétrica

Ce travail porte sur l'étude de structures multicouches à gradient de propriétés (FGM : Functionnally Graded Materials). Ces matériaux sont apparus afin d'obtenir des dépôts aux caractéristiques nouvelles et innovantes. Les FGM sont désormais présents dans divers applications de haute technologie.Un système multicouche à gradient de composition entre le cuivre et le nickel, a fait l'objet d'une étude expérimentale par l'application de la technique des ultrasons laser (LU) couplée à une étude numérique basée sur le formalisme de Stroh et la méthode de la matrice de raideur. Le travail de thèse est organisé autour de quatre chapitres. Le premier chapitre est dédié à l'aspect théorique de la propagation des ondes de surface dans une structure multicouche et à gradient de propriétés. Ainsi, un développement des méthodes numériques pour les matériaux dotés de la piézoélectricité est fourni. Le second chapitre se consacre à l'élaboration des échantillons utilisés dans notre étude et obtenus par pulvérisation cathodique. Le troisième chapitre présente la méthode opto-acoustique utilisée pour caractériser les échantillons réalisés. le dernier chapitre présente les résultats expérimentaux, confrontés aux résultats théoriques, décrivant le comportement dispersif des multicouches submicrométriques. / This thesis focuses on the study of multilayered and FGM systems (FGM : Functionnally Graded Materials). The main purpose of this type of materials is to obtain deposits with new and innovative features and to increase the fracture toughness. From now on, FGM have been used in various high technology applications.A multilayer system with a composition gradient of copper and nickel was studied experimentally by the application of the laser ultrasonics (LU) technique which was coupled to a theoretical study based on the ordinary differential equations (ODE) and the Stiffness Matrix Method (SMM). This PhD thesis is organized around four chapters. The first chapter is dedicated to a theoretical study of the propagation behavior of surface acoustic wave (SAW) in a multilayer system with à gradient of properties. Thus, the numerical methods developped for the piezoelectric materials (FGPM) are presented. The second chapter is devoted to describe the setup for making the samples used in this study which were obtained by sputtering technique. The third chapter presents the experimental study dedicated to the measurement of surface wave velocities in many crystal orientations. The last chapter of the manuscript presents experimental results, compared to the theoretical results, describing the dispersive behavior of submicrometer multilayers.