38 research outputs found

    Comparação de desempenho entre arquiteturas de distribuição de clock baseadas em interconexões de cobre e de nanotubo de carbono

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    Monografia (graduação)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Elétrica, 2014.Nesta monografia será realizado o estudo sobre o desempenho de arquiteturas de distribuição de clock de alta velocidade baseadas em interconexões de nanotubos de carbono e de cobre. As arquiteturas de distribuição estudadas serão: H-tree X-Tree e Mesh Tree. Dessa forma, os modelos de circuitos do SWCNT bundle (single-walled carbon nanotube bundle) e do cobre serão apresentados e o estudo comparativo do desempenho destes materiais será realizado, considerando diferentes comprimentos das interconexões. Além disso, o efeito destas interconexões será analisado com buffers em seus terminais, também para diferentes dimensões. Com este propósito, as interconexões e os circuitos serão simulados usando o software LTSPICE

    Análise do desempenho de interconexões de nanotubo de carbono e de cobre em circuitos NANO-CMOS

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    Monografia (graduação)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Elétrica, 2012.Nesta monografia será realizado o estudo de nanotubos de carbono como possíveis substitutos do cobre em interconexões em circuitos integrados NANO-CMOS. Dessa forma, os modelos de circuitos do SWCNT (single-walled carbon nanotube) e do cobre serão apresentados e o estudo comparativo do desempenho destes materiais será realizado, considerando diferentes comprimentos das interconexões. Além disso, o efeito destas interconexões será analisado no multiplicador de 4 bits, também para diferentes comprimentos. O multiplicador utilizado é implementado utilizando modelos de transistores NANO-CMOS diversos. Com este propósito, as interconexões e demais circuitos serão simuladas usando o software LTSPICE

    Estudo sobre o consumo de energia em redes-em-chip baseadas em dispositivos nanoeletrônicos

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    Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Elétrica, 2017.A evolução da indústria eletrônica que permitiu a implementação de arquiteturas de múltiplos núcleos foi motivada principalmente pelo consumo de energia, pois elas oferecem melhor desempenho e menor dissipação de potência do que os sistemas de processamento único. Com o aumento do número de núcleos em um único chip, a arquitetura de comunicação que interliga esses núcleos começou a ganhar importância. Assim, para resolver os problemas de interconectividade e comunicação dos sistemas em chip, a arquitetura de comunicação do tipo redes-em-chip (NoC - Network-on-Chip) tem sido proposta como uma solução altamente estruturada pela comunidade científica. Estimativas do consumo de energia das arquiteturas de comunicação devem ser realizadas no início do projeto, pois a comunicação do chip representa uma porção significante do total de energia e área consumida pelo chip. Neste contexto, este trabalho objetiva estudar sobre o consumo de energia em NoCs baseadas em dispositivos nanoeletrônicos, por meio de um modelo analítico previamente apresentado. Para obter o consumo total de energia da comunicação do chip, esse modelo utiliza como base alguns parâmetros, tais como, a energia das interconexões e dos roteadores, e a distribuição de probabilidade de comunicação. O objetivo principal deste trabalho é verificar quantitativamente qual a contribuição da nanoeletrônica na redução do consumo de energia, na arquitetura de comunicação do tipo NoC, com ênfase no estudo das interconexões. Desta forma, são feitas simulações para verificar o comportamento da latência e da energia das interconexões que conectam os roteadores da rede, em função dos nós de tecnologia, bem como, é realizada a comparação do consumo de energia entre redes com roteadores nanoeletrônicos e redes com roteadores CMOS. Por fim, é realizada uma análise comparativa entre o consumo de energia de redes com interconexões de cobre e nanotubo de carbono, utilizando roteadores nanoeletrônicos. Os resultados obtidos neste trabalho mostram que a nanoeletrônica é uma tecnologia que aparenta ser uma solução promissora na redução do consumo de energia dos futuros chips e dispositivos.The evolution of the electronic industry that allowed the implementation of multi-core architectures was motivated mainly by the energy consumption, since they offer better performance and less power dissipation than the single processing systems. With the increase in the number of cores on a single chip, the communication architecture that interconnects these cores began to gain importance. Thus, to solve the problems of interconnectivity and communication of the systems in chip, Networks-on-Chip (NoC) communication architecture has been proposed as a solution highly structured by the scientific community. Estimates of the energy consumption of communication architectures should be carried out at the beginning of the project because the communication of the chip represents a significant portion of the total energy and area consumed by the chip. In this context, this work aims to study energy consumption in NoCs based on nanoelectronic devices, through an analytical model previously presented. To obtain the total energy consumption of the chip communication, this model uses as base some parameters, such as the energy of the interconnections and the routers, and the Communication Probability Distribution. The main objective of this work is to verify quantitatively the contribution of nanoelectronics in the reduction of energy consumption in NoC communication architecture, with emphasis on the study of interconnections. In this way, simulations are performed to verify the latency and energy behavior of the interconnections that connect the routers of the network, as a function of the technology nodes, as well as, the comparison of the energy consumption between networks with nanoelectronic routers and networks with CMOS routers is made. Finally, a comparative analysis was performed between the energy consumption of networks with copper and carbon nanotube interconnections using nanoelectronic routers. The results obtained in this work show that nanoelectronics is a technology that appears to be a promising solution in reducing the energy consumption of future chips and devices

    Solid State Circuits Technologies

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    The evolution of solid-state circuit technology has a long history within a relatively short period of time. This technology has lead to the modern information society that connects us and tools, a large market, and many types of products and applications. The solid-state circuit technology continuously evolves via breakthroughs and improvements every year. This book is devoted to review and present novel approaches for some of the main issues involved in this exciting and vigorous technology. The book is composed of 22 chapters, written by authors coming from 30 different institutions located in 12 different countries throughout the Americas, Asia and Europe. Thus, reflecting the wide international contribution to the book. The broad range of subjects presented in the book offers a general overview of the main issues in modern solid-state circuit technology. Furthermore, the book offers an in depth analysis on specific subjects for specialists. We believe the book is of great scientific and educational value for many readers. I am profoundly indebted to the support provided by all of those involved in the work. First and foremost I would like to acknowledge and thank the authors who worked hard and generously agreed to share their results and knowledge. Second I would like to express my gratitude to the Intech team that invited me to edit the book and give me their full support and a fruitful experience while working together to combine this book

    Challenges and solutions for large-scale integration of emerging technologies

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    Title from PDF of title page viewed June 15, 2021Dissertation advisor: Mostafizur RahmanVitaIncludes bibliographical references (pages 67-88)Thesis (Ph.D.)--School of Computing and Engineering and Department of Physics and Astronomy. University of Missouri--Kansas City, 2021The semiconductor revolution so far has been primarily driven by the ability to shrink devices and interconnects proportionally (Moore's law) while achieving incremental benefits. In sub-10nm nodes, device scaling reaches its fundamental limits, and the interconnect bottleneck is dominating power and performance. As the traditional way of CMOS scaling comes to an end, it is essential to find an alternative to continue this progress. However, an alternative technology for general-purpose computing remains elusive; currently pursued research directions face adoption challenges in all aspects from materials, devices to architecture, thermal management, integration, and manufacturing. Crosstalk Computing, a novel emerging computing technique, addresses some of the challenges and proposes a new paradigm for circuit design, scaling, and security. However, like other emerging technologies, Crosstalk Computing also faces challenges like designing large-scale circuits using existing CAD tools, scalability, evaluation and benchmarking of large-scale designs, experimentation through commercial foundry processes to compete/co-exist with CMOS for digital logic implementations. This dissertation addresses these issues by providing a methodology for circuit synthesis customizing the existing EDA tool flow, evaluating and benchmarking against state-of-the-art CMOS for large-scale circuits designed at 7nm from MCNC benchmark suits. This research also presents a study on Crosstalk technology's scalability aspects and shows how the circuits' properties evolve from 180nm to 7nm technology nodes. Some significant results are for primitive Crosstalk gate, designed in 180nm, 65nm, 32nm, and 7nm technology nodes, the average reduction in power is 42.5%, and an average improvement in performance is 34.5% comparing to CMOS for all mentioned nodes. For benchmarking large-scale circuits designed at 7nm, there are 48%, 57%, and 10% improvements against CMOS designs in terms of density, power, and performance, respectively. An experimental demonstration of a proof-of-concept prototype chip for Crosstalk Computing at TSMC 65nm technology is also presented in this dissertation, showing the Crosstalk gates can be realized using the existing manufacturing process. Additionally, the dissertation also provides a fine-grained thermal management approach for emerging technologies like transistor-level 3-D integration (Monolithic 3-D, Skybridge, SN3D), which holds the most promise beyond 2-D CMOS technology. However, such 3-D architectures within small form factors increase hotspots and demand careful consideration of thermal management at all integration levels. This research proposes a new direction for fine-grained thermal management approach for transistor-level 3-D integrated circuits through the insertion of architected heat extraction features that can be part of circuit design, and an integrated methodology for thermal evaluation of 3-D circuits combining different simulation outcomes at advanced nodes, which can be integrated to traditional CAD flow. The results show that the proposed heat extraction features effectively reduce the temperature from a heated location. Thus, the dissertation provides a new perspective to overcome the challenges faced by emerging technologies where the device, circuit, connectivity, heat management, and manufacturing are addressed in an integrated manner.Introduction and motivation -- Cross talk computing overview -- Logic simplification approach for Crosstalk circuit design -- Crostalk computing scalability study: from 180 nm to 7 nm -- Designing large*scale circuits in Crosstalk at 7 nm -- Comparison and benchmarking -- Experimental demonstration of Crosstalk computing -- Thermal management challenges and mitigation techniques for transistor-level- 3D integratio

    Réalisation, caractérisation et modélisation de nanofils pour application RF

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    Les composants nano électroniques ont fait l'objet d'intérêt marqué, au sein de la communauté des concepteurs de circuits radiofréquence au cours de ces dernières années. Non seulement ils peuvent présenter des caractéristiques intéressantes, mais ils offrent la perspective d'améliorations de la miniaturisation des composants les plus avancés. Les nanotubes de carbone et les nanofils conducteurs sont attendus comme pouvant potentiellement constituer des blocs utilisables dans les futurs circuits aux très faibles dimensions. Les conducteurs métalliques sont utilisés depuis longtemps pour réaliser des composants passifs dans les circuits intégrés radio fréquence, cependant très peu de travaux ont été menés sur des conducteurs ayant des dimensions nanométriques et fonctionnant dans le domaine millimétrique. L'objectif de cette thèse est d'exploré les propriétés RF de conducteurs métalliques aux dimensions nanométriques et la possibilité de les intégrés dans des circuits utilisant des technologies CMOS. Dans cette thèse, des lignes de transmission et des antennes intégrées sur puce, utilisant des nanofils conducteurs, ont été conçues et réalisées en utilisant un processus de fabrication "top-down". Les caractéristiques en terme de transmission de signal ont été observées expérimentalement dans le domaine millimétrique par la mesure de paramètres S. Deux types de lignes ont été conçus : des lignes micro-ruban de faible épaisseur et des lignes coplanaires. Les caractéristiques en fonction de la fréquence du signal d'excitation ont été analysées. Différents paramètres comme la largeur, l'épaisseur, le nombre de nanofils et la distance entre les nanofils ont été étudiés. De plus, un modèle de propagation basée sur des ondes quasi-TEM a été proposé pour obtenir une compréhension fine du comportement physique des nanofils. Par ailleurs, une étude approfondies concernant les techniques d'épluchage (de-embedding) a été menée afin d'améliorer la précision des mesures. En parallèle, des antennes dipôle et IFA, utilisant des nanofils, ont été réalisées pour tester la transmission sans ligne de propagation. Différentes dimensions de conducteurs et différents types de substrats ont été utilisés pour étudier leurs propriétés et obtenir les meilleures performances.Nano-electronic devices have attracted much attention for the radio frequency engineering community in recent years. They not only exhibit compelling characteristics but show promises to enhance the miniaturization of modern devices. Carbon nanotubes and conducting nanowires are believed to be potential building blocks for ultra-small chip of the future. Metallic wires have long been utilized as the passive components in the RF integrated circuit but there are very few studies on their nanoscale counterpart particularly up to millimeter-wave frequencies. The focus of this thesis is to explore RF properties of metallic nanowires and their potentials to be integrated in CMOS communication technology. In this thesis, transmission lines and on-chip antennas integrated with metallic nanowires were developed enabled by top-down fabrication processes. The signal transmission properties of such devices were characterized well into the mm-wave regime based on two-port S-parameters measurement. Two types of nano-transmission lines were designed: thin film microstrip lines and coplanar waveguides. Their transmission characteristics as a function of frequencies were analysed. Different parameters like the linewidth, thickness, number of nanowires, and the distance between the wires were examined. In addition, a quasi-TEM propagation model was proposed to provide a further insight into the physical behaviours of the nanowires. Moreover, a comprehensive study regarding the de-embedding techniques was carried out in order to improve measurement accuracy. Meanwhile, on-chip dipoles and planar meander-line inverted F antenna were implemented to test the wireless signal transmission of the metallic nanowires. Various wires dimensions and substrates were designed to exploit their characteristics thus facilitating better transmission.SAVOIE-SCD - Bib.électronique (730659901) / SudocGRENOBLE1/INP-Bib.électronique (384210012) / SudocGRENOBLE2/3-Bib.électronique (384219901) / SudocSudocFranceF

    Tuning cellular functionality and mechanobiology via carbon nanotubes based scaffolds

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    La rigenerazione tissutale che occorre in seguito all\u2019insorgere di malattie e/o lesioni attraverso l\u2019organizzazione delle cellule in organi/tessuti, \ue8 fortemente indebolita dagli stimoli meccanici e biochimici esercitati dall\u2019ambiente extracellulare danneggiato, i quali impattano definitivamente sul destino cellulare. Per guidare l\u2019abilit\ue0 rigenerativa dei tessuti, possono essere sfruttati biomateriali mimanti la complessa architettura fisiologica. La matrice extracellulare (ECM), tuttavia, \ue8 caratterizzata da un intricato network di elementi nanostrutturati che si adattano agli input cellulari fornendo gli stimoli attraverso i quali le cellule attivano i percorsi di meccanotrasduzione necessari per la modulazione delle loro funzioni. Poich\ue9 le cellule normalmente interagiscono con queste nanostrutture presenti nel loro ambiente, un requisito fondamentale per i biomateriali mimetici \ue8 il fatto di possederli. Non \ue8 sorprendente, quindi, il grande interesse rivolto ai nanotubi di carbonio (CNTs) negli ultimi decenni, grazie alle tante similarit\ue0 con la ECM, morfologiche e dimensionali, oltre alle loro peculiari propriet\ue0 chimico-fisiche e meccaniche. Essi hanno inequivocabilmente dimostrato la loro abilit\ue0 di potenziare l\u2019attivit\ue0 elettrica della rete neurale. Negli studi precedenti, CNTs purificati erano depositati su substrato di vetro mediante drop-casting. Qui, abbiamo dimostrato, per la prima volta, che i CNTs cresciuti direttamente su substrati di silicio tramite deposizione chimica da fase vapore catalitica (CCVD) preservano lo stesso effetto di potenziamento con il vantaggio, per\uf2, di poter modulare facilmente le propriet\ue0 della matrice a base di carbonio che possono essere utilizzate senza la necessit\ue0 di alcuna purificazione chimica e/o funzionalizzazione semplificando notevolmente il loro uso. Con lo scopo di sfruttare le potenzialit\ue0 del nostro tappeto di CNTs come biomateriale artificiale per la rigenerazione tissutale, sono richiesti risultati sperimentali da tecniche complementari. Tuttavia, i nostri substrati cresciuti su silicio, mancano della trasparenza ottica, primariamente a causa del silicio stesso. Questo limita l\u2019uso di tutte quelle tecniche di caratterizzazione che richiedono di visualizzare le cellule \u2018attraverso\u2019 il campione (l\u2019elettrofisiologia e la microscopia in campo chiaro). Con tale scopo, abbiamo sviluppato una nuova strategia per fabbricare substrati trasparenti di CNTs (tCNTs) attraverso il CCVD direttamente su un substrato trasparente e controllando accuratamente la loro lunghezza. Abbiamo dimostrato che tali supporti a base di carbonio inducono su colture ippocampali lo stesso potenziamento sinaptico, in precedenza osservato per i substrati tradizionali (drop-casted-CNTs). Abbiamo investigato, inoltre, la loro abilit\ue0 di supportare la crescita del complesso tessuto neuronale come le colture Entorinali-Ippocampali (EHCs) dimostrando, per la prima volta, che il nostro nanomateriale pu\uf2 aiutare riconnessione funzionale dei tessuti neuronali lesionati. I tCNTs possono anche essere sfruttati per migliorare le attuali strategie adottate per i trattamenti delle malattie cardiovascolari (CAVD) che ad oggi non determinano una soluzione a lungo termine. In particolare, il nostro interesse \ue8 stato rivolto alla calcificazione della valvola aortica (CAVD), legata a variazioni della ECM, in termini di composizione, organizzazione e propriet\ue0 meccaniche. Di conseguenza, sulla base del ruolo cruciale della ECM in questa malattia e considerando, inoltre, le similarit\ue0 tra CNTs ed ECM, abbiamo studiato il loro effetto sulle cellule valvolari interstiziali (pVICs), costituenti principali della valvola aortica. Abbiamo dimostrato che essi possono fornire un ambiente fisiologico per lo \u2018sviluppo\u2019 delle VICs in cui la quantit\ue0 dei miofibroblasti, legato alla CAVD, \ue8 simile a quello caratterizzante le valvole sane.Natural tissue self-regeneration, occurring at the onset of injury or disease through the self-organization of cells into organs/tissues, is strongly impaired by mechanical and biochemical cues from the damaged extracellular environment, which impact cell fate. To drive tissue self-renewal ability, artificial biomaterials mimicking the complex architecture of the physiological cell microenvironment are highly desired. The natural extracellular matrix (ECM), however, displays an intricate network of nanoscale structures, whose morphology adapts to cell input, providing in turn mechanical cues to the surrounding cells which activate the biochemical and mechano-transduction pathways necessary for the modulation of their functions. Since cells normally interact with typical nanometer-scale elements present in their environment, nanoscale features are the first essential requirement for the design of biomimetic scaffolds. In this context, it is not surprising that carbon nanotubes (CNTs), owning various similarities with the native ECM, physico-chemical and mechanical properties, have captured increased attention. CNTs unequivocally demonstrated their ability to perturb electrical activity of neuronal networks. In previous studies, cell cultures were grown on purified CNTs deposited on supporting surfaces via drop casting. Here, we demonstrate that CNTs directly grown on a supporting silicon surface by catalytic chemical vapor deposition (CCVD) technique bear the same potentiating effect, with the added value of easy modulation of the CNT matrix properties. In our approach we developed a novel and well-controllable synthesis method leading to the realization of various CNTs-based architectures which could be employed as-produced, without the necessity of any chemical purification /functionalization, thus significantly simplifying their use. To further exploit the potential of our CNTs for tissue regeneration, experimental results from complementary techniques are required. Such substrates grown on silicon surfaces, however, lack of optical transparency, preventing its exploitation with all the investigation techniques requiring to optically visualize cells \u2018through\u2019 the specimens (electrophysiology and bright field microscopy). Therefore, we developed a novel strategy to fabricate transparent carbon nanotubes substrates (tCNTs) by synthesizing these carbon nanostructure via CCVD directly on a transparent substrate (i.e. fused silica) and finely controlling their length. We demonstrated that this original fabrication \u201crecipe\u201d gives rise to CNT carpet able to induce the same synaptic potentiation in hippocampal cells we observed in the case of opaque CNT films and drop-casted layers. We further investigated the ability of tCNTs to support the growth of complex neuronal tissues as intact and lesioned Entorhinal-Hippocampal slice cultures (EHCs), demonstrating that our nanomaterial can help in promoting a successful reconnection and functional cross talk between the two slices after the lesion. CNTs-based scaffolds can be exploited also to improve the standard strategies adopted for the treatments of cardiovascular diseases (CVD) which currently do not lead to a long-term solution. In particular, our interest has been directed towards calcific aortic valve diseases (CAVD), strongly related to significant changes in ECM organization, composition and mechanical properties. Therefore, based on the crucial role of ECM properties have on the progression of this disease and considering also the peculiar CNTs ability to structurally emulate the native ECM, we interfaced our novel tCNTs scaffold with porcine valve interstitial cells (pVICs), the predominant constituent of aortic valve. We demonstrated that tCNTs substrates can provide a physiological environment for VICs development in which the amount of myofibroblasts, related to CAVD, is similar to that characterizing healthy valves
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