High performance and low cost sensors based on microelectromechanical systems (MEMS) have become commonplace in today's world. MEMS sensors, such as accelerometers, gy- roscopes, pressure sensors, and microphones, are routinely used in consumer electronics, automobiles, industrial and aerospace applications. Basically, all these devices mea- sure tiny displacements of micromachined mechanical structures in response to external stimuli. One of the widely used techniques to detect these displacements is piezoresistive sensing. Piezoresistive sensors are popular in MEMS due to their simplicity and robustness. Traditionally, silicon has been the material of choice for piezoresistors due to its high strain sensitivity or gauge factor. Whereas metal lm piezoresistors typically have low gauge factor that puts them out of favour when compared to silicon. But metal lm piezoresistors have several advantages compared to their semiconductor counterparts, including simple and low-cost fabrication, low resistivity and generally low noise. Low resistance sensors become desirable particularly when the devices are scaled down to nanoelectromechanical systems (NEMS), where signal-to-noise ratio (SNR) performance becomes crucial. Enhancing the gauge factor of metal lms while keeping their low resistance advantage can dramatically improve their SNR performance for NEMS. This thesis reports a simple method we have developed to enhance the gauge factor of metal lm piezoresistors. We demonstrate this method on specially designed micro- cantilever devices. Using controlled electromigration, we are able to engineer the microstructure of gold lm and transform it into a locally inhomogeneous conductor which resembles a percolation network. This results in more than 100 times higher gauge factor at low to moderate sensor resistance. The SNR possible with our piezoresistor at high frequencies exceeds that of most available systems by at least an order of magnitude. Our locally inhomogeneous metal lm piezoresistor is a promising candidate for high-performance NEMS-based sensors of the future.

Frontend and backend wearout mechanisms are major reliability concerns for modern microprocessors. In this research, a framework which contains modules for negative bias temperature instability (NBTI), positive bias temperature instability (PBTI), hot carrier injection (HCI), gate-oxide breakdown (GOBD), backend time-dependent dielectric breakdown (BTDDB), electromigration (EM), and stress-induced voiding (SIV) is proposed to analyze the impact of each wearout mechanism on state-of-art microprocessors and to accurately estimate microprocessor lifetimes due to each wearout mechanism. Taking into account the detailed thermal profiles, electrical stress profiles and a variety of use scenarios, composed of a fraction of time in operation, a fraction of time in standby, and a fraction of time when the system is off, this work provides insight into lifetime-limiting wearout mechanisms, along with the reliability-critical microprocessor functional units for a system. This enables circuit designers to know if their designs will achieve an adequate lifetime and further make any updates in the designs to enhance reliability prior to committing the designs to manufacture.

Due to the aggressive downscaling of the CMOS technology, power and current densities are increasing inside the chip. The limiting current conduction capacity(106 Acm−2)and thermal conductivity(201Wm−1K−1 for Al and 400 Wm−1K−1 for Cu) of the existing interconnects materials has given rise to different electro-thermal issues such a shot-spot formation, electromigration, etc. Exploration of new materials with high thermal conductivity and current conduction has thus attracted much attention for future integrated circuit technology. Among all the elemental materials, carbon nanomaterials (graphene and carbon nanotube) possess exceptionally high thermal (600-7000 Wm−1K−1) and current( ~108 -109 Acm−2)conduction properties at room temperature, which makes them potential candidate for interconnect materials. At the same time development of efficient energy harvesting techniques are also becoming important for future wireless autonomous devices. The excess heat generated at the hot-spot location could be used to drive an electronic circuit through a suitable thermoelectric generator. As the See beck coefficient of graphene is reported to be the highest among all elementary semiconductors, exploration of thermoelectric properties of graphene is very important. This thesis investigates the electrothermal and thermoelectric properties of metallic single walled carbon nanotube (SWCNT) and single layer graphene (SLG) for their possible applications in thermal management in next generation integrated circuits. A closed form analytical solution of Joule-heating equation in metallic SWCNTs is thus proposed by considering a temperature dependent lattice thermal conductivity (κ) on the basis of three-phonon Umklapp, mass-difference and boundary scattering phenomena. The solution of which gives the temperature profile over the SWCNT length and hence the location of hot-spot(created due to the self-heating inside the chip) can be predicted. This self-heating phenomenon is further extended to estimate the electromigration performance and mean-time-to-failure of metallic SWCNTs. It is shown that metallic SWCNTs are less prone to electromigration. To analyze the electro-thermal effects in a suspended SLG, a physics-based flexural phonon dominated thermal conductivity model is developed, which shows that κ follows a T1.5 and T−2 law at lower(<300 K) and higher temperature respectively in the absence of isotopes(C13 atoms). However in the presence of isotopic impurity, the behavior of κ sharply deviates from T−2 at higher temperatures. The proposed model of κ is found to be in excellent match with the available experimental data over a wide range of temperatures and can be utilized for an efficient electro-thermal analysis of encased/supported graphene. By considering the interaction of electron with in-plane and flexural phonons in a doped SLG sheet, a physics-based electrical conductance(σ) model of SLG under self-heating effect is also discussed that particularly exhibits the variation of electrical resistance with temperature at different current levels and matches well with the available experimental data. To investigate the thermoelectric performance of a SLG sheet, analytical models for See beck effect coefficient (SB) and specific heat (Cph) are developed, which are found to be in good agreement with the experimental data. Using those analytical models, it is predicted that one can achieve a thermoelectric figure of merit(ZT) of ~ 0.62 at room temperature by adding isotopic impurities(C13 atoms) in a degenerate SLG. Such prediction shows the immense potential of graphene in waste-heat recovery applications. Those models for σ, κ, SB and Cph are further used to determine the time evolution of temperature distribution along suspended SLG sheet through a transient analysis of Joule-heating equation under the Thomson effect. The proposed methodology can be extended to analyze the graphene heat-spreader theory and interconnects and graphene based thermoelectrics.

Ce travail constitue une contribution à l’étude de la synergie entre le vieillissement accéléré et l’évolution de la robustesse aux évènements singuliers pour les technologies MOS avancées. Ce manuscrit expose le travail fait autour de la Caractérisations des mécanismes de dégradation NBTI, HCI, TDDB et Electromigration sur les structures de tests conçues dans le véhicule de test NANOSPACE en technologie CMOS LP 65 nm. Il décrit aussi l’évaluation de la robustesse face aux évènements singuliers après un vieillissement de type NBTI sur les chaines de portes logiques (inverseurs, NOR, bascules D). Cette dernière partie nous a permis de démontrer que le vieillissement de type NBTI améliore la robustesse face aux SET dans ce cas d’étude. / This work is a contribution to the study of the synergy between accelerated aging and the evolution of robustness to single event effects for advanced MOS technologies.This manuscript describes the work done around the characterization of degradation mechanisms NBTI, HCI, TDDB and Electromigration on test structures designed in the NANOSPACE test vehicle on CMOS 65 nm Low Power technology. It also describes the evaluation of the robustness to Single Events Effects after NBTI aging on chains of logic gates (inverters, NOR, D flip-flops). This last part allows to show that the NBTI aging improves the robustness to SET in this case of study.

<div>A microheater and resistance temperature detector (RTD) are designed and fabricated for various applications. First, a hierarchical manifold microchannel heatsink with an integrated microheater and RTDs is demonstrated. Microfluidic cooling within the embedded heat sink improves heat dissipation, with two-phase operation offering the potential for dissipation of very high heat fluxes while maintaining moderate chip temperatures. To enable multi-chip stacking and other heterogeneous packaging approaches, it is important to densely integrate all fluid flow paths into the device. Therefore, the details of heatsink layouts and fabrication processes are introduced. Characterization of two-phase cooling as well as reliability of the microheater/RTDs are discussed. In addition, another application of microheater for mining particle detection using interdigitated capacitive sensor. While current personal monitoring devices are optimized for monitoring microscale particles, a higher resolution technique is required to detect sub-micron and nanoscale particulate matters (PM) due to smaller volume and mass of the particles. The detection capability of the capacitive sensor for sub-micron and nanoparticles are presented, and an incorporated microheater improved stable capacitive sensor reading under air flow and various humidity. </div><div>This paper also introduces the characterization of nanomaterials such as metallic nanowires (NWs) and single layer graphene. First, the copper nanowire (CuNW)/graphene hybrid networks for transparent conductors (TC) is investigated. Though indium tin oxide (ITO) has been widely used, demands for the next generation of TC is increasing due to a limited supply of indium. Thus, the optical and electrical properties of CuNW/graphene hybrid network are compared with other transparent conductive materials including ITO. Secondly, silver nanowire (AgNW) growth technique using electrodeposition is introduced. A vertically aligned branched AgNW arrays is made using a porous anodic alumina template and the optical properties of the structure are discussed.</div><div><br></div>

Motion of ions under the influence of electric field has been a subject of scientific interest for many decades. Capillary electrophoresis in particular benefited greatly from this research and mathematical models of electromigration applicable to capillary electrophoresis have been developed. As the sophistication of the models grew, so did the computational demands to evaluate them. In order to fully exploit the possibilities of advanced mathematical models a computer implementation capable of solving non-trivial problems at sufficient speed is necessary. This dissertation thesis explores applications of computer implementations of mathematical models re- lated to electromigration in two different areas. The main focus of this thesis is on the topic of linear theory of electromigration. We discuss the extension of the linear theory of electromigration beyond of just acid-base equilibria and computer implementation of this extented theory which is specialized to include complex-forming equilibria in order to be able to deal with affinity capillary electrophoresis prob- lems. Some technical aspects of the computer implementation are also discussed. This is followed upon by investigating certain selected affinity capillary electrophoresis systems. The purpose of this investi- gation is to re-derive...

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Die vorliegende Arbeit verfolgt das Ziel, Cu(Ag)-Dünnschichten als potentiellen Werkstoff für Leiterbahnen in der Mikroelektronik zu untersuchen. Für die Beurteilung dieses Materialsystems wurden vier Schwerpunkte bezüglich der Schichtcharakterisierung definiert: Herstellung, Gefüge, thermomechanische Eigenschaften, Elektromigrationsresistenz. Grundlage sämtlicher Untersuchungen ist eine geeignete Probenpräparation. In Anlehnung an Technologien, die zur Zeit bei der Herstellung von reinen Cu-Leiterbahnen Anwendung finden, erfolgte die Beschichtung der Cu(Ag)-Schichten (Dicke bis 1 µm) galvanisch aus einem schwefelsauren Elektrolyten unter Additiveinsatz auf thermisch oxidierten Siliziumwafern. Hierbei war nicht nur die Abscheidung von ganzflächigen Dünnschichten, sondern auch die Beschichtung auf strukturierte Substrate von Interesse. Die erzeugten Schichtproben werden in ihren Gefügeeigenschaften, vergleichend zu reinen Kupferschichten, charakterisiert. Hierzu zählen Korngrößen und -orientierungen, thermisches Gefügeverhalten, Einbau, Verteilung und Segregation von Silber und Fremdstoffen sowie die elektrischen Eigenschaften. Von grundsätzlicher Bedeutung für das Elektromigrationsverhalten und damit für die Zuverlässigkeit und das Leistungsvermögen sind die thermomechanischen Eigenschaften. Diese werden an ausgedehnten Schichten mit der Substratkrümmungsmessung bis zu Temperaturen von 500°C beschrieben. Die Diskussion des mechanischen Schichtverhaltens umfasst sowohl thermische als auch temporale Charakteristika. Die Untersuchungen geben einen Einblick in die wirkenden Mechanismen des Stofftransports und des Spannungsabbaus. Den Abschluss der Arbeit stellen erste Experimente zum Elektromigrationsverhalten der Cu(Ag)-Dünnschichten dar. Den Kern dieser Analysen bilden Messungen an sog. Blech-Strukturen (Materialdriftexperimente). Hierbei werden geeignete Technologien für die mikrotechnologische Herstellung von derartigen Cu(Ag)-Strukturen vorgestellt. Anhand erster Messungen wird das Elektromigrationsverhalten von Cu(Ag)-Metallisierungen in seinen Grundcharakteristika beschrieben.

Les nano-antennes optiques constituent un élément clé pour le contrôle et l’intéraction lumière/matière à l’échelle nanométrique. Ces systèmes opèrent dans le domaine de l’optique visible et proche infrarouge. Les propriétés de ces composants sont contrôlées en modifiant la taille, la forme et le matériau utilisé. Ces paramètres sont ajustés par les processus de fabrication de l’antenne. Dans le domaine des radio-fréquences, le tuner permet d’ajuster la fréquence de résonance de l’antenne de façon dynamique. Nous avons dans le cadre de cette thèse voulu adapter ce concept de tuner au domaine de l’optique. Le principe employé consiste à changer la résistance de charge de l’antenne, c’est-à-dire l’indice du milieu électrique environnant. Pour cela, nous avons utilisé un matériau anisotrope constitué de molécules de cristaux liquides. L’indice optique est alors modifié par l ’application d’un champ électrique statique. Le changement des propriétés spectrales ainsi que de diffusion d’une antenne de type dimère sont ici démontrées.Toujours en analogie avec les antennes radio-fréquences, nous avons étudié la propriété de transduction électron-photon dans le cas des antennes optiques. Dans ce but, nous avons considéré deux configurations. La première concerne l’utilisation de nanotubes de carbone placés dans une configuration de transistor à effet de champ. Ces objets émettent de la lumière par une recombinaison de paires électrons-trous dans le domaine des longueurs d’ondes Télécom. La seconde configuration emploie des jonctions tunnels fabriquées par électro-migration. Dans ce cas là, la jonction est assimilée à une antenne à interstice. A cause des faibles dimensions des jonctions (autour de 1 nm), nous nous sommes intéressés à la réponse en optique non linéaire de ses objets. Cette technique permet de localiser la jonction tunnel grâce à une forte exaltation du signal. L’etude des différentes caractérisques de ses jonctions sont ici présentées. Une fois la transduction du signal réalisée par l’antenne radiofréquence, celui-ci est acheminé via une ligne de transmission. A l’ échelle nanométrique, les guides plasmoniques s’avèrent être un type de structure approprié. Dans ce cas, les guides peuvent à la fois servir d’´electrode mais aussi de guide. Dans le cadre de cette thèse, nous avons étudié par microscopie à fuites radiatives, dans l’espace direct et réciproque, la plus simple des géométries : le guide ruban métallique. Nous avons cherché à comprendre, pourquoi ce type de structure présente une largeur de coupure. / Optical nano-antennae are the new class of components to control light/matterinteraction at the nanoscale. These devices are operating in the visible to near infraredpart of the spectrum. The properties of these nano objects are controlled by theform, the size and the material.In the radio frequency domain, the tuner changes dynamically the operatingwavelength of the antenna. In this thesis work, we search to transfer this conceptto the nanoscale. The principle is to change the load impedance of the antenna, i.e.changing the optical index of the dielectric medium around the nano-object. Forthat we used anisotropic liquid cristal molecules. The value of the optical index iscontrolled by applying an external electrical static field. The effects on the spectraland scattering properties are demonstrated on a single dimer nano-antenna.However with the microwave antennae, we were interesting to the electronsphotonstransduction with an optical antenna. In this mind, we studied two differentsconfigurations. The first one concerns the use of carbon nanotubes placedin a field effect transistor configuration. These nano-objects emit light in the Telecomwavelength range by a radiative combination of electrons and holes. the secondconfiguration used planar tunnel junctions made by electromigration. In this case,the junctions are view as an optical gap antenna. Because the gap are very small(around 1 nm), we have studied the nonlinear optical response of these objects. Thisnonlinear optical characterization allows to determined the location of the tunneljunctions by an enhancement of the optical signal. The results about the properties(electrical and optical) of these tunnel junctions are presented.Once the transduction by the radio frequency antenna is achieved, this signalis transporting by a transmission line. By transposition at the nanoscale, the plasmonicswaveguides prove to be the most appropriate structure. In this case, theycould be used as an electrode or a waveguide. In this thesis work, we have studiedby leakage radiation microscopy, in the direct and reciprocal space, the simplestgeometry : plasmonic metal strips. We search to understand why these structureshave a cut-off width.

Die vorliegende Arbeit verfolgt das Ziel, Cu(Ag)-Dünnschichten als potentiellen Werkstoff für Leiterbahnen in der Mikroelektronik zu untersuchen. Für die Beurteilung dieses Materialsystems wurden vier Schwerpunkte bezüglich der Schichtcharakterisierung definiert: Herstellung, Gefüge, thermomechanische Eigenschaften, Elektromigrationsresistenz. Grundlage sämtlicher Untersuchungen ist eine geeignete Probenpräparation. In Anlehnung an Technologien, die zur Zeit bei der Herstellung von reinen Cu-Leiterbahnen Anwendung finden, erfolgte die Beschichtung der Cu(Ag)-Schichten (Dicke bis 1 µm) galvanisch aus einem schwefelsauren Elektrolyten unter Additiveinsatz auf thermisch oxidierten Siliziumwafern. Hierbei war nicht nur die Abscheidung von ganzflächigen Dünnschichten, sondern auch die Beschichtung auf strukturierte Substrate von Interesse. Die erzeugten Schichtproben werden in ihren Gefügeeigenschaften, vergleichend zu reinen Kupferschichten, charakterisiert. Hierzu zählen Korngrößen und -orientierungen, thermisches Gefügeverhalten, Einbau, Verteilung und Segregation von Silber und Fremdstoffen sowie die elektrischen Eigenschaften. Von grundsätzlicher Bedeutung für das Elektromigrationsverhalten und damit für die Zuverlässigkeit und das Leistungsvermögen sind die thermomechanischen Eigenschaften. Diese werden an ausgedehnten Schichten mit der Substratkrümmungsmessung bis zu Temperaturen von 500°C beschrieben. Die Diskussion des mechanischen Schichtverhaltens umfasst sowohl thermische als auch temporale Charakteristika. Die Untersuchungen geben einen Einblick in die wirkenden Mechanismen des Stofftransports und des Spannungsabbaus. Den Abschluss der Arbeit stellen erste Experimente zum Elektromigrationsverhalten der Cu(Ag)-Dünnschichten dar. Den Kern dieser Analysen bilden Messungen an sog. Blech-Strukturen (Materialdriftexperimente). Hierbei werden geeignete Technologien für die mikrotechnologische Herstellung von derartigen Cu(Ag)-Strukturen vorgestellt. Anhand erster Messungen wird das Elektromigrationsverhalten von Cu(Ag)-Metallisierungen in seinen Grundcharakteristika beschrieben.