This thesis treats the development of packaging and integration methods for the cost-efficient encapsulation and packaging of microelectromechanical (MEMS) devices. The packaging of MEMS devices is often more costly than the device itself, partly because the packaging can be crucial for the performance of the device. For devices which contain liquids or needs to be enclosed in a vacuum, the packaging can account for up to 80% of the total cost of the device. The first part of this thesis presents the integration scheme for an optical dye thin film NO2-gas sensor, designed using cost-efficient implementations of wafer-scale methods. This work includes design and fabrication of photonic subcomponents in addition to the main effort of integration and packaging of the dye-film. A specific proof of concept target was for NO2 monitoring in a car tunnel. The second part of this thesis deals with the wafer-scale packaging methods developed for the sensing device. The developed packaging method, based on low-temperature plastic deformation of gold sealing structures, is further demonstrated as a generic method for other hermetic liquid and vacuum packaging applications. In the developed packaging methods, the mechanically squeezed gold sealing material is both electroplated microstruc- tures and wire bonded stud bumps. The electroplated rings act like a more hermetic version of rubber sealing rings while compressed in conjunction with a cavity forming wafer bonding process. The stud bump sealing processes is on the other hand applied on completed cavities with narrow access ports, to seal either a vacuum or liquid inside the cavities at room temperature. Additionally, the resulting hermeticity of primarily the vacuum sealing methods is thoroughly investigated. Two of the sealing methods presented require permanent mechanical fixation in order to complete the packaging process. Two solutions to this problem are presented in this thesis. First, a more traditional wafer bonding method using tin-soldering is demonstrated. Second, a novel full-wafer epoxy underfill-process using a microfluidic distribution network is demonstrated using a room temperature process. / <p>QC 20130325</p>

Electron Beam Induced Deposition (EBID) is an emerging additive nanomanufacturing tool which enables growth of complex 3-D parts from a variety of materials with nanoscale resolution. Fundamentals of EBID and its application to making a robust, low-contact-resistance electromechanical junction between a Multiwall Carbon Nanotube (MWNT) and a metal electrode are investigated in this thesis research. MWNTs are promising candidates for next generation electrical and electronic devices, and one of the main challenges in MWNT utilization is a high intrinsic contact resistance of the MWNT-metal electrode junction interface. EBID of an amorphous carbon interface has previously been demonstrated to simultaneously lower the electrical contact resistance and to improve mechanical characteristics of the MWNT-electrode junction. In this work, factors contributing to the EBID formation of the carbon joint between a MWNT and an electrode are systematically explored via complimentary experimental and theoretical investigations. A comprehensive dynamic model of EBID using residual hydrocarbons as a precursor molecule is developed by coupling the precursor mass transport, electron transport and scattering, and surface deposition reaction. The model is validated by comparison with experiments and is used to identify different EBID growth regimes and the growth rates and shapes of EBID deposits for each regime. In addition, the impact of MWNT properties, the electron beam impingement location and energy on the EBID-made carbon joint between the MWNT and the metal electrode is critically evaluated. Lastly, the dominant factors contributing to the overall electrical resistance of the MWNT-based electrical interconnect and relative importance of the mechanical contact area of the EBID-made carbon joint to MWNT vs. that to the metal electrode are determined using carefully designed experiments.

The Atomic Force Microscope (AFM) is an instrument that is capable of measuring intermolecular forces between single molecules. Multi-Parameter Force Spectroscopy (MPFS) is a technique that uses the AFM. MPFS enables the acquisition of force curves and thermal resonance of the system under investigation. This technique can shed light on the mechanical behavior at the molecular level. Improvements described herein have enhanced the sensitivity of MPFS over background noise. This investigation focuses on the mechanical and interfacial properties of three carbon nanostructures: long nanotubes, nanocoils, and nanoloops. Different types of adhesion are encountered, measured and discussed: friction, rupture, and peeling. The elastic modulus of long carbon nanotubes is calculated from frequency shifts when the system is put into tension. An elastica model is applied to the post-buckled carbon nanotubes, which enables the estimation of the static coefficient of friction on chemically modified surfaces. The compression of a nanocoil at large contact angles reveals that changes in oscillation amplitude do not occur from damping, but from adding stiffness into the systems measured herein. This result is counter to the assumptions of dynamic force spectroscopy. Finally, carbon nanoloops are brought into and out of contact with several different surfaces. The force curve and frequency response of the system shows the difference between rupture and peeling. The results presented herein lead to a better understanding of the mechanical and tribological properties of the carbon nanostructures.

Because of their outstanding characteristics, micro/nano-mechanical (MM) structures have found a plethora of applications in wireless communications and sensing. Many of these MM structures utilize mechanical vibrations (or phonons) at megahertz or gigahertz frequencies for their operation. On the other hand, the periodic atomic structure of crystals is the fundamental phenomenon behind the new era of electronics technology. Such atomic arrangements lead to a periodic electric potential that modifies the propagation of electrons in the crystals. In some crystals, e.g. silicon (Si), this modification leads to an electronic band gap (EBG), which is a range of energies electrons can not propagate with. Discovering EBGs has made a revolution in the electronics and through that, other fields of technology and the society. Inspired by these trends of science and technology, I have designed and developed integrated MM periodic structures that support large phononic band gaps (PnBGs), which are ranges of frequencies that phonons (and elastic waves) are not allowed to propagate. Although PnBGs may be found in natural crystals due to their periodic atomic structures, such PnBGs occur at extra high frequencies (i.e., terahertz range) and cannot be easily engineered with the current state of technology. Contrarily, the structures I have developed in this research are made on planar substrates using lithography and plasma etching, and can be deliberately engineered for the required applications. Although the results and concepts developed in this research can be applied to other substrates, I have chosen silicon (Si) as the substrate of choice for implementing the PnBG structure due to its unique properties. I have also designed and implemented the fundamental building blocks of MM systems (e.g., resonators and waveguides) based on the developed PnBG structures and have shown that low loss and efficient MM devices can be made using the PnBG structures. As an example of the possible applications of these PnBG structures, I have shown that an important source of loss, the support loss, can be suppressed in MM resonators using PnBG structures. I have also made improvements in the characteristics of the developed MM PnBG resonators by developing and employing PnBG waveguides. I have further shown theoretically, that photonic band gaps (PtBGs) can also be simultaneously obtained in the developed PnBGs structures. This can lead to improved photon-phonon interactions due to the effective confinement of optical and mechanical vibrations in such structures. For the design, fabrication, and characterization of the structures, I have developed and utilized complex and efficient simulation tools, including a finite difference time domain (FDTD), a plane wave expansion (PWE), and a finite elements (FE) tool, each of which I have developed either completely from scratch, or by modification of an existing tool to suit my applications. I have also developed and used advanced micro-fabrication recipes, and characterization methods for realizing and characterizing these PnBG structures and devices. It is agued that by using the same ideas these structures can be fabricated at nanometer scales to operate at ultra high frequency ranges. I believe my contributions has opened a broad venue for new MM structures based on PnBG structures with superior characteristics compared to the conventional devices.

In the past two decades much effort has been put in the characterization of the mechanical<p>and surface properties at the nano-scale in order to conceive reliable N/MEMS<p>(Nano and Micro ElectroMechanical Systems) applications. Techniques like nanoindentation,<p>nanoscratching, atomic force microscopy have become widely used to measure<p>the mechanical and surface properties of materials at sub-micro or nano scale. Nevertheless,<p>many phenomena such us pile-up and pop-in as well as surface anomalies<p>and roughness play an important role in the accurate determination of the materials<p>properties. The first goal of this report is to study the infulence of these sources of data<p>distortion on the experimental data. The results are discussed in the first experimental<p>chapter.<p>On the other hand, conceptors would like to adapt/tune the mechanical and surface<p>properties as a function of the required application so as to adapt them to the industrial<p>need. Coatings are usually applied to materials to enhance performances and reliability<p>such as better hardness and elastic modulus, chemical resistance and wear resistance.<p>In this work, the magnetron sputtering technique is used to deposit biocompatible thin<p>layers of different compositions (titanium carbide, titanium nitride and amorphous<p>carbon) over a titanium substrate. The goal of this second experimental part is the<p>study of the deposition parameters influence on the resulting mechanical and surface<p>properties.<p>New materials such as nanocrystal superlattices have recently received considerable<p>attention due to their versatile electronic and optical properties. However, this new<p>class of material requires robust mechanical properties to be useful for technological<p>applications. In the third and last experimental chapter, nanoindentation and atomic<p>force microscopy are used to characterize the mechanical behavior of well ordered lead<p>sulfide (PbS) nanocrystal superlattices. The goal of this last chapter is the understanding<p>of the deformation process in order to conceive more reliable nanocrystal<p>superlattices. / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished

Le couplage fort entre le transport électronique dans une boîte quantique à un seul niveau et un oscillateur nano-mécanique couplé capacitivement peut conduire à une transition vers un état mécaniquement bistable et bloqué en courant. Son observation est à portée de main dans les expériences de pointe menées sur les nanotubes de carbone. Nous étudions donc la réponse mécanique du système et plus précisément la fonction spectrale de déplacement, la réponse linéaire à une solicitation externe et le comportement pendant le retour à l'équilibre. Nous montrons qu'il existe une relation étroite entre les grandeurs électriques (telles le courant électrique et la fonction spectrale des fluctuations du courant) et mécaniques. Nous constatons qu'en augmentant le couplage électromécanique, les deux fonctions spectrales présentent un pic qui s'élargit et se déplace vers les basses fréquences alors que le temps de déphasage de l'oscillateur se raccourcit. Ces effets sont maximaux à la transition où les non-linéarités dominent la dynamique et sont robustes vis-à-vis de l'effet des fluctuations extérieures et de la dissipation. Ces caractéristiques fortes ouvrent la voie à la détection de la transition vers l'état de blocage du courant dans des dispositifs actuellement étudiées par plusieurs groupes. / The strong coupling between electronic transport in a single-level quantum dot and a capacitively coupled nano-mechanical oscillator may lead to a transition towards a mechanically-bistable and blocked-current state. Its observation is at reach in carbonnanotube state-of-art experiments. Therefore, we investigate the mechanical response of the system, namely the displacement spectral function, the linear response to a driving, and the ring-down behavior, and the electric response, namely the electric current and current spectral function. We show that a close relation between electric and mechanical quantities exists. We find that, by increasing the lectromechanical coupling, the peak in both spectral functions broadens and shifts at low frequencies while the oscillator dephasing time shortens. These effects are maximum at the transition where nonlinearities dominate the dynamics, and are robust towards the effect of external uctuations and dissipation. These strong signatures open the way to detect the blockade transition in devices currently studied by several groups.

Avec une limite de détection ultime pouvant atteindre le yoctogramme (1 yg = 10-24 g), les nanosystèmes électromécaniques (NEMS) employés comme capteurs gravimétriques présentent un fort potentiel pour la détection ultra-sensible et sans marquage de molécules biologiques. A l’heure actuelle, plusieurs défis restent cependant à relever avant de pouvoir envisager de manière réaliste leur utilisation comme outils de biodétection. Ces travaux de thèse adressent en particulier l’intégration du moyen de transduction et le développement de stratégies de biofonctionnalisation. En vue de répondre à la première problématique, l’intégration d’une couche piézoélectrique à base de Titano-Zirconate de Plomb (PZT) selon une approche de fabrication collective de réseaux de NEMS par voie descendante a été développée et caractérisée.Deux approches de biofonctionnalisation adaptées à une organisation de NEMS en réseaux,respectivement basées sur le dépôt localisé de matériel biologique par impression moléculaire et sur la structuration par photolithographie d’une couche bioréceptrice à base de polymères à empreintes moléculaires (MIP), ont ensuite été mises en oeuvre et ont permis de démontrer une première preuve de concept. Ces différentes contributions constituent un premier pas dans le développement des NEMS pour des applications de biodétection. / With an ultimate limit of detection down to the yoctogram regime (1 yg = 10-24 g),nanoelectromechanical systems (NEMS) resonators used as ultra-sensitive and label-free gravimetric sensors have a high potential for biodetection applications. To date, several challenges currently limit their wide spread use as viable biosensing tools. This PhD thesis addresses the issues related to the transducer integration and the biofunctionnalization. A Lead Zirconate Titatane (PZT)-based piezoelectric transducer has been implemented according to a top-down approach compatible with collective fabrication of NEMS arrays. Two biofunctionnalization strategies, suitable for a NEMS array organization and based on the localized deposition of biological material assisted by microcontact printing and the patterning of molecularly imprinted polymers (MIP) by photolithography, have also been investigated and first proof-of-concept biosensors were demonstrated. These various contributions have the potential to drive future advancements in the realm of NEMS as effective biosensing tools.

<p>With the advent of increasingly complex radio systems at higher frequencies and the slowing of traditional CMOS process scaling with power concerns, there has been an increased focus on integration, architectural, and material innovations as a continued path forward in MEMS and logic. This work presents the first comprehensive experimental study of resonant body transistors in a commercial 14nm FinFET process, demonstrating differential radio frequency transduction as a function of transistor biasing through electrostatic, piezoresistive, and threshold voltage modulation. The impact of device design changes on unreleased resonator performance are further explored, highlighting the importance of phononic confinement in achieving an f*Q product of 8.2*10¹¹ at 11.73 GHz. Also shown are initial efforts towards the understanding of coupled oscillator architectures and a perovskite nickelate material system. Finally, development of resonators based on two-dimensional materials, whose scale is particularly attractive for high-frequency nano-mechanical resonators and acoustic devices, is discussed. Experiments towards dry transfer of tellurene flakes using geometries printed via two photon polymerization are presented along with optimization of a fabrication process for gated RF devices, presenting new opportunities for high-frequency electro-mechanical interactions in this topological material. </p>

L'objectif de notre thèse de <p>doctorat est d’étudier et de décrire les propriétés chimiques et mé- <p>caniques du moteur moléculaire F1 -ATPase. Le moteur F1 -ATPase <p>est un moteur rotatif, d’aspect sphérique et d’environ 10 nanomètre <p>de rayon, qui utilise l’énergie de l’hydrolyse de l’ATP comme car- <p>burant moléculaire. <p>Des questions fondamentales se posent sur le fonctionnement de <p>ce moteurs et sur la quantité de travail qu’il peut fournir. Il s’agit <p>de questions qui concernent principalement la thermodynamique <p>des processus irréversibles. De plus, comme ce moteur est de <p>taille nanométrique, il est fortement influencé par les fluctuations <p>moléculaires, ce qui nécessite une approche stochastique. <p>C’est en créant deux modéles stochastiques complémentaires de <p>ce moteur que nous avons contribué à répondre à ces questions <p>fondamentales. <p>Le premier modèle discuté au chapitre 5 de la thèse, est un mod- <p>èle continu dans le temps et l’espace, décrit par des équations de <p>Fokker-Planck, est construit sur des résultats expérimentaux. <p>Ce modèle tient compte d’une description explicite des fluctua- <p>tions affectant le degré de liberté mécanique et décrit les tran- <p>sitions entre les différents états chimiques discrets du moteur, <p>par un processus de sauts aléatoires entre premiers voisins. Nous <p>avons obtenus des résultats précis concernant la chimie d’hydrolyse <p>et de synthèse de l’ATP, et pour les dépendences du moteur en les <p>différentes variables mécaniques, à savoir, la friction et le couple <p>de force extérieur, ainsi que la dépendence en la température. <p>Les résultats que nous avons obtenus avec ce modèle sont en ex- <p>cellent accord avec les observations expérimentales. <p>Le second modèle est discret dans l’espace et continu dans le <p>temps et est décrit dans le chapitre 6. L’analyse des résultats <p>obtenus par simulations numériques montre que le modèle est <p>en accord avec les observations expérimentales et il permet en <p>outre de dériver des grandeurs thermodynamiques analytique- <p>ment, décrites au chapitre 4, ce que le modèle continu ne permet <p>pas. <p>La comparaison des deux modèles révele la nature du fonction- <p>nement du moteur, ainsi que son régime de fonctionnement loin <p>de l’équilibre. Le second modèle a éte soumis récemment pour <p>publication. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

FeCrAl alloys are being investigated as candidate materials for replacing zirconium based alloys as nuclear reactor fuel cladding because of their superior high temperature oxidation resistance in steam environments. Unirradiated FeCrAl as well as Fe²⁺ ion irradiated FeCrAl to a peak dose of 20DPA were mechanically tested and compared against each other. Nanohardness tests were performed on both the unirradiated and irradiated conditions and it was found that the irradiated alloy was about 1GPa harder than its unirradiated counterpart. TEM <i>in situ</i> tensile tests were performed using the Bruker push to pull device alongside a PI95 Picoindenter on single crystals with grain orientations 001, 011 and 111. The unirradiated 001 grains tended to fail without yielding in a brittle manner while the irradiated 001 grain yielded and reached an ultimate tensile strength before failure. The unirradiated 011 grains behaved in a mixed manner, where one failed without yielding and one slipped many times before failing. The irradiated 011 grain yielded and failed quickly thereafter. The unirradiated 111 grain yielded, slipped and twinned before failing and both irradiated 111 grains slipped. Two general trends were observed. One, each unirradiated single grain was stronger than its irradiated counterpart. This trend is indicative of the ion irradiated microstructure facilitating bulklike mechanical behavior in the irradiated samples whereas the unirradiated samples exhibited mechanical size effects due to either the total lack of preexisting defects or the ability for existing defects to escape easily to the surface of the sample resulting in a pristine, defect free sample. Two, regardless of irradiation condition, the 001 grain orientation was brittle, the 011 grain orientation deformed in a mixed brittle/ductile manner and the 111 grain orientation was ductile through all tests. These results are indicative of the geometry of the BCC crystal structure and the slip system involving these orientations.