As CMOS device sizes shrink, the channel electric field becomes higher and the hot carrier (HC) effect becomes more significant. When the oxide is scaled down to less than 3 nm, gate oxide breakdown (BD) often takes place. As a result, oxide trapping and interface generation cause long term performance drift and related reliability problems in devices and circuits. The RF front-end circuits include low noise amplifier (LNA), local oscillator (LO) and mixer. It is desirable for a LNA to achieve high gain with low noise figure, a LO to generate low noise signal with sufficient output power, wide tuning range, and high stability, and a mixer to up-convert or down-convert the signal with good linearity. However, the RF front-end circuit performance is very sensitive to the variation of device parameters. The experimental results show that device performance is degraded significantly subject to HC stress and BD. Therefore, RF front-end performance is degraded by HC and BD effects. With scaling and increasing chip power dissipation, operating temperatures for device have also been increasing. Another reliability concern, which is the negative bias temperature instability (NBTI) caused by the interface traps under high temperature and negative gate voltage bias, arises when the operation temperature of devices increases. NBTI has received much attention in recent year and it is found that NIT is present for all stress conditions and NOT is found to occur at high VG. Therefore, the probability of BD in pMOSFET increases with temperature since trapped charges during the NBTI process increase, thus resulting in percolation, a main cause of oxide degradation. The above effects can cause significant degradations in transistors, thus leading to the shifts of RF performance. This dissertation focuses on the following aspects: (1) RF performance degradation in nMOSFET and pMOSFET due to hot carrier and soft breakdown effects are examined experimentally and will be used for circuit application in the future. (2) A modeling method to analyze the gate oxide breakdown effects on RF nMOSFET has been proposed. The device performance drifts due to gate oxide breakdown are examined, breakdown spot resistance and total gate capacitance are extracted before and after stress for 0.16 um CMOS technology. (3) LC voltage controlled oscillator (VCO) performance degradation due to gate oxide breakdown effect is evaluated. (4) NBTI, HCI and BD combined effects on RF performance degradation are investigated. A physical picture illustrating the NBTI induced BD process is presented. A model to evaluate the time-to-failure (TTF) during NBTI is developed. DCIV method is used to extract the densities of NIT and NOT. Measurements show that there is direct correlation between the steplike increase in the gate current and the oxide-trapped charge (NOT). However, Breakdown has nothing to do with interface traps (NIT). (5) It is found that the degradation due to NSH stress is more severe than that of NS stress at high temperature. A model aiming to evaluate the stress-induced degradation is also developed.

MOS current mode logic (MCML) offers low noise digital circuits that reduce noise that can cripple analog components in mixed-signal integrated circuits, when compared to CMOS digital circuits. An MCML standard cell library was developed for the Cadence Virtuoso Integrated Circuit (IC) design software that gives IC designers the ability to design complex, low noise digital circuits for use in mixed-signal and noise sensitive systems at a high level of abstraction, allowing them to get superior products to market faster than competitors. The MCML standard cell library developed and presented here allows for fast development of mixed signal circuits by providing quiet digital building block gates that reduce the simultaneous switching noise (SSN) by an order of magnitude over conventional CMOS based designs [3]. This thesis project developed the following digital gates in MCML as a standard cell library for general-purpose low noise and very low noise applications: inverter, buffer, NAND, AND, NOR, OR, XOR, NXOR, 2:1 MUX, CMOS to MCML, MCML to CMOS, and double edge triggered flip-flop (DETFF).

Scope and contents: The static and dynamic electrical characteristics of silicon n-channel MOS FETs are studied down to cryogenic temperatures. Particular emphasis is directed towards the effect of interface states on the temperature dependence of both the pinch-off voltage and 1/f noise. / No abstract included. / Thesis / Master of Engineering (MEngr)

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This project will be based in an objective and as well as subjective study related to Quality of Experience in a video conference application, appear.in. Indeed the study puts emphasis on finding possible correlations between Quality of Service parameters, that in the study are represented by some of the most meaningful network parameters, and contextual parameters with Quality of Experience. To achieve this the study was based in two different scenarios using two test environments. One is based on having an all free test and the other conducted in a created test-bad for monitoring and altering network parameters to see how user respond to the changes. Both scenarios were accompanied by a survey that provided useful information about the subjective perception of different individuals that took part in the testing phase.The project is divided in two phases where we set up the required environments for the test and then we process results to find correlation between the above mentioned parameters.In the end of the project all the results and the conclusions are presented providing a clearer view for what was done. The project itself might represent a good foundation to be used in the future for other studies related to video conferencing application.

Health-related quality of life (HRQL) measures taken before and after coronary artery bypass grafting (CABG) aid in determining meaningful patient-perceived outcomes associated with alternative clinical interventions. This study compared performance of the Medical Outcomes Study Short Form-36 (MOS SF-36) subscales for Physical Functioning (PF), Role Physical (RP), Mental Health (MH), and Role Emotional (RE) against two other questionnaires, i.e. the Veteran's Specific Activity Questionnaire (VSAQ: self-efficacy for vigorous physical activity) and the Beck Depression Inventory (BDI-II: mental-emotional functioning). Seventy-one patients (59-M; 12-F; age, Mean + SD = 63 ± 8.6 years) were administered these three questionnaires just before and 3 months following CABG surgery. Score distributions were evaluated for the pre- and post-surgery measurements, as were change scores after CABG. All measures except the MOS SF-36 subscales for RP and RE showed statistically significant change after CABG (p<0.01). Only the subscales of RP and RE demonstrated substantial ceiling (21.0% and 56.3%) and floor effects (49.3% and 16.9%). Evaluation of individual change scores after CABG indicated that 59% and 62% of the patients, respectively, had clinically meaningful increases in the two measures of physical capability, i.e. PF and VSAQ. In contrast, 60% and 72% of patients, respectively, showed no clinically meaningful changes in the two measures of emotional functioning, i.e. RE and BDI-II scores. Chi-square analyses revealed that use of scales with similar definitional constructs resulted in significantly different surgical outcomes for the following: PF vs VSAQ (p<0.001), RP vs VSAQ (p<0.02); and MH vs BDI-II (p<0.0001). These findings illustrate the limitations in performance of the MOS SF-36 for assessing changes of importance in HRQL after CABG. The VSAQ and BDI-II, two simple measures of physical and emotional functioning that are fundamentally similar to those contained in the MOS SF-36, appear to be sensitive markers for detecting changes in these important outcomes after CABG surgery. / Master of Science

L’avenir de la recherche sur les maladies du cerveau repose sur le développement de nouvelles technologies qui permettront de comprendre comment cet organe si complexe traite, intègre et transfère l’information. Parmi celles-ci, l’optogénétique est une technologie révolutionnaire qui permet d’utiliser de la lumière afin d’activer sélectivement les neurones du cortex d’animaux transgéniques pour observer leur effet dans un vaste réseau biologique. Ce cadre expérimental repose typiquement sur l’observation de l’activité neuronale de souris transgéniques, car elles peuvent exprimer une grande variété de gènes et de maladies et qu’elles sont peu couteuses. Toutefois, la plupart des appareils de mesure ou de stimulation optogénétique disponible ne sont pas appropriés, car ils sont câblés, trop lourds et/ou trop simplistes. Malheureusement, peu de systèmes sans fil existent, et ces derniers sont grandement limités par la bande passante requise pour transmettre les données neuronales, et ils ne fournissent pas de stimulation optogénétique multicanal afin de stimuler et observer plusieurs régions du cerveau. Dans les dispositifs actuels, l’interprétation des données neuronales est effectuée ex situ, alors que la recherche bénéficierait grandement de systèmes sans fil assez intelligents pour interpréter et stimuler les neurones en boucle fermée, in situ. Le but de ce projet de recherche est de concevoir des circuits analogiques-numériques d’acquisition et de traitement des signaux neuronaux, des algorithmes d’analyse et de traitement de ces signaux et des systèmes electro-optiques miniatures et sans fil pour : i) Mener des expériences combinant l’enregistrement neuronal et l’optogénétique multicanal haute résolution avec des animaux libres de leurs mouvements. ii) Mener des expériences optogénétiques synchronisées avec l’observation, c.-à-d. en boucle fermée, chez des animaux libres de leurs mouvements. iii) Réduire la taille, le poids et la consommation énergétique des systèmes optogénétiques sans fil afin de minimiser l’impact de la recherche chez de petits animaux. Ce projet est en 3 phases, et ses principales contributions ont été rapportées dans dix conférences internationales (ISSCC, ISCAS, EMBC, etc.) et quatre articles de journaux publiés ou soumis, ainsi que dans un brevet et deux divulgations. La conception d’un système optogénétique haute résolution pose plusieurs défis importants. Notamment, puisque les signaux neuronaux ont un contenu fréquentiel élevé (_10 kHz), le nombre de canaux sous observation est limité par la bande passante des transmetteurs sans fil (2-4 canaux en général). Ainsi, la première phase du projet a visé le développement d’algorithmes de compression des signaux neuronaux et leur intégration dans un système optogénétique sans fil miniature et léger (2.8 g) haute résolution possédant 32 canaux d’acquisition et 32 canaux de stimulation optique. Le système détecte, compresse et transmet les formes d’onde des potentiels d’action (PA) produits par les neurones avec un field programmable gate array (FPGA) embarqué à faible consommation énergétique. Ce processeur implémente un algorithme de détection des PAs basé sur un seuillage adaptatif, ce qui permet de compresser les signaux en transmettant seulement les formes détectées. Chaque PA est davantage compressé par une transformée en ondelette discrète (DWT) de type Symmlet-2 suivie d’une technique de discrimination et de requantification dynamique des coefficients. Les résultats obtenus démontrent que cet algorithme est plus robuste que les méthodes existantes tout en permettant de reconstruire les signaux compressés avec une meilleure qualité (SNDR moyen de 25 dB _ 5% pour un taux de compression (CR) de 4.2). Avec la détection, des CR supérieurs à 500 sont rapportés lors de la validation in vivo. L’utilisation de composantes commerciales dans des systèmes optogénétiques sans fil augmente / la taille et la consommation énergétique, en plus de ne pas être optimisée pour cette application. La seconde phase du projet a permis de concevoir un système sur puce (SoC) complementary metal oxide semiconductor (CMOS) pour faire de l’enregistrement neuronal et de optogénétique multicanal, permettant de réduire significativement la taille et la consommation énergétique comparativement aux alternatives commerciales. Ceci est une contribution importante, car c’est la première puce à être doté de ces deux fonctionnalités. Le SoC possède 10 canaux d’enregistrement et 4 canaux de stimulation optogénétique. La conception du bioamplificateur inclut une bande passante programmable (0.5 Hz - 7 kHz) et un faible bruit referré à l’entré (IRN de 3.2 μVrms), ce qui permet de cibler différents types de signaux biologiques (PA, LFP, etc.). Le convertisseur analogique numérique (ADC) de type Delta- Sigma (DS) MASH 1-1-1 est conçu pour fonctionner de faibles taux de sur-échantillonnage (OSR _50) pour réduire sa consommation et possède une résolution programmable (ENOB de 9.75 Bits avec un OSR de 25). Cet ADC exploite une nouvelle technique réduisant la taille du circuit en soustrayant la sortie de chaque branche du DS dans le domaine numérique, comparativement à la méthode analogique classique. La consommation totale d’un canal d’enregistrement est de 11.2 μW. Le SoC implémente un nouveau circuit de stimulation optique basé sur une source de courant de type cascode avec rétroaction, ce qui permet d’accommoder une large gamme de LED et de tensions de batterie comparativement aux circuits existants. Le SoC est intégré dans un système optogénétique sans fil et validé in vivo. À ce jour et en excluant ce projet, aucun système sans-fil ne fait de l’optogénétique en boucle fermée simultanément au suivi temps réel de l’activité neuronale. Une contribution importante de ce travail est d’avoir développé le premier système optogénétique multicanal qui est capable de fonctionner en boucle fermée et le premier à être validé lors d’expériences in vivo impliquant des animaux libres de leurs mouvements. Pour ce faire, la troisième phase du projet a visé la conception d’un SoC CMOS numérique, appelé neural decoder integrated circuit (ND-IC). Le ND-IC et le SoC développé lors de la phase 2 ont été intégrés dans un système optogénétique sans fil. Le ND-IC possède 3 modules : 1) le détecteur de PA adaptatif, 2) le module de compression possédant un nouvel arbre de tri pour discriminer les coefficients, et 3) le module de classement automatique des PA qui réutilise les données générées par le module de détection et de compression pour réduire sa complexité. Un lien entre un canal d’enregistrement et un canal de stimulation est établi selon l’association de chaque PA à un neurone, grâce à la classification, et selon l’activité de ce neurone dans le temps. Le ND-IC consomme 56.9 μW et occupe 0.08 mm2 par canal. Le système pèse 1.05 g, occupe un volume de 1.12 cm3, possède une autonomie de 3h, et est validé in vivo. / The future of brain research lies in the development of new technologies that will help understand how this complex organ processes, integrates and transfers information. Among these, optogenetics is a recent technology that allows the use of light to selectively activate neurons in the cortex of transgenic animals to observe their effect in a large biological network. This experimental setting is typically based on observing the neuronal activity of transgenic mice, as they express a wide variety of genes and diseases, while being inexpensive. However, most available neural recording or optogenetic devices are not suitable, because they are hard-wired, too heavy and/or too simplistic. Unfortunately, few wireless systems exist, and they are greatly limited by the required bandwidth to transmit neural data, while not providing simultaneous multi-channel neural recording and optogenetic, a must for stimulating and observing several areas of the brain. In current devices, the analysis of the neuronal data is performed ex situ, while the research would greatly benefit from wireless systems that are smart enough to interpret and stimulate the neurons in closed-loop, in situ. The goal of this project is to design analog-digital circuits for acquisition and processing of neural signals, algorithms for analysis and processing of these signals and miniature electrooptical wireless systems for: i) Conducting experiments combining high-resolution multi-channel neuronal recording and high-resolution multi-channel optogenetics with freely-moving animals. ii) Conduct optogenetic experiments synchronized with the neural recording, i.e. in closed loop, with freely-moving animals. iii) Increase the resolution while reducing the size, weight and energy consumption of the wireless optogenetic systems to minimize the impact of research with small animals. This project is in 3 phases, and its main contributions have been reported in ten conferences (ISSCC, ISCAS, EMBC, etc.) and four published journal papers, or submitted, as well as in a patent and two disclosures. The design of a high resolution optogenetic system poses several challenges. In particular, since the neuronal signals have a high frequency content (10 kHz), the number of chanv nels under observation is limited by the bandwidth of the wireless transmitters (2-4 channels in general). Thus, the first phase of the project focused on the development of neural signal compression algorithms and their integration into a high-resolution miniature and lightweight wireless optogenetics system (2.8g), having 32 recording channels and 32 optical stimulation channels. This system detects, compresses and transmits the waveforms of the signals produced by the neurons, i.e. action potentials (AP), in real time, via an embedded low-power field programmable gate array (FPGA). This processor implements an AP detector algorithm based on adaptive thresholding, which allows to compress the signals by transmitting only the detected waveforms. Each AP is further compressed by a Symmlet-2 discrete wavelet transform (DWT) followed dynamic discrimination and requantification of the DWT coefficients, making it possible to achieve high compression ratios with a good reconstruction quality. Results demonstrate that this algorithm is more robust than existing approach, while allowing to reconstruct the compressed signals with better quality (average SNDR of 25 dB 5% for a compression ratio (CR) of 4.2). With detection, CRs greater than 500 are reported during the in vivo validation. The use of commercial components in wireless optogenetic systems increases the size and power consumption, while not being optimized for this application. The second phase of the project consisted in designing a complementary metal oxide semiconductor (CMOS) system-on-chip (SoC) for neural recording and multi-channel optogenetics, which significantly reduces the size and energy consumption compared to commercial alternatives. This is important contribution, since it’s the first chip to integrate both features. This SoC has 10 recording channels and 4 optogenetic stimulation channels. The bioamplifier design includes a programmable bandwidth (0.5 Hz -7 kHz) and a low input-referred noise (IRN of 3.2 μVrms), which allows targeting different biological signals (AP, LFP, etc.). The Delta-Sigma (DS) MASH 1-1-1 low-power analog-to-digital converter (ADC) is designed to work with low OSR (50), as to reduce its power consumption, and has a programmable resolution (ENOB of 9.75 bits with an OSR of 25). This ADC uses a new technique to reduce its circuit size by subtracting the output of each DS branch in the digital domain, rather than in the analog domain, as done conventionally. A recording channel, including the bioamplifier, the DS and the decimation filter, consumes 11.2 μW. Optical stimulation is performed with an on-chip LED driver using a regulated cascode current source with feedback, which accommodates a wide range of LED parameters and battery voltages. The SoC is integrated into a wireless optogenetic platform and validated in vivo. / To date and excluding this project, no wireless system is making closed-loop optogenetics simultaneously to real-time monitoring of neuronal activity. An important contribution of this work is to have developed the first multi-channel optogenetic system that is able to work in closed-loop, and the first to be validated during in vivo experiments involving freely-moving animals. To do so, the third phase of the project aimed to design a digital CMOS chip, called neural decoder integrated circuit (ND-IC). The ND-IC and the SoC developed in Phase 2 are integrated within a wireless optogenetic system. The ND-IC has 3 main cores: 1) the adaptive AP detector core, 2) the compression core with a new sorting tree for discriminating the DWT coefficients, and 3 ) the AP automatic classification core that reuses the data generated by the detection and compression cores to reduce its complexity. A link between a recording channel and a stimulation channel is established according to the association of each AP with a neuron, thanks to the classification, and according to the bursting activity of this neuron. The ND-IC consumes 56.9 μW and occupies 0.08 mm2 per channel. The system weighs 1.05 g, occupies a volume of 1.12 cm3, has an autonomy of 3h, and is validated in vivo.