Tagged repair techniques for defect tolerance in hybrid nano/CMOS architecture

We propose two new repair techniques for hybrid nano/CMOS computing architecture with lookup table based Boolean logic. Our proposed techniques use tagging mechanism to provide high level of defect tolerance and we present theoretical equations to predict the repair capability including an estimate of the repair cost. The repair techniques are efficient in utilization of spare units and capable of targeting upto 20% defect rates, which is higher than recently reported repair techniques

Belle II Technical Design Report

The Belle detector at the KEKB electron-positron collider has collected almost 1 billion Y(4S) events in its decade of operation. Super-KEKB, an upgrade of KEKB is under construction, to increase the luminosity by two orders of magnitude during a three-year shutdown, with an ultimate goal of 8E35 /cm^2 /s luminosity. To exploit the increased luminosity, an upgrade of the Belle detector has been proposed. A new international collaboration Belle-II, is being formed. The Technical Design Report presents physics motivation, basic methods of the accelerator upgrade, as well as key improvements of the detector.Comment: Edited by: Z. Dole\v{z}al and S. Un

Development of a microfluidic device for gaseous formaldehyde sensing = Développement d\u27un dispositif microfluidique pour la détection de formaldéhyde à l\u27état gazeux

Formaldehyd (HCHO) ist eine chemische Verbindung, die bei der Herstellung einer großen Zahl von Haushaltsprodukten verwendet wird.Charakteristisch ist seine hohe Flüchtigkeit aufgrund einer niedrigen Siedetemperatur ($T = - 19\ ℃$). Daher ist HCOH fast überall als Luftschadstoff in Innenräumen vorhanden. Die Miniaturisierung analytischer Systeme zu Handheld-Gerät hat das Potenzial, nicht nur effizientere, sondern auch empfindlichere Instrumente für die Echtzeitüberwachung dieses gefährlichen Luftschadstoffs zu ermöglichen. Die vorliegende Doktorarbeit präsentiert die Entwicklung eines Mikrofluidik-Geräts für die Erfassung von HCHO basierend auf der Hantzsch-Reaktion.Hierbei wurde der Schwerpunkt auf die Komponente für Fluoreszenzdetektion gelegt. Es wurde eine umfangreiche Literaturrecherche durchgeführt, die es erlaubt, den Stand der Technik auf dem Gebiet der Miniaturisierung des Fluoreszenzsensors zusammenzufassen. Auf Grund dieser Studie wurde ein modulares Fluoreszenzdetektionskonzept vorgeschlagen, das um einen CMOS-Bildsensor (CIS) herum entwickelt wurde. Zwei dreischichtige Fluidikzellenkonfigurationen (Konfiguration 1: Quarz - SU-8 3050 - Quarz und Konfiguration 2: Silizium - SU-8 3050 - Quarz) wurden in Betracht gezogen und parallel unter den gleichen experimentellen Bedingungen getestet. Die Verfahren der Mikrofabrikation der fluidischen Zellen wurden detailliert beschrieben, einschließlich des Integrationsprozesses der Standardkomponenten und der experimentellen Verfahren. Der CIS-basierte Fluoreszenzdetektor bewies seine Leistungsfähigkeit, eine anfängliche HCHO-Konzentration von 10 µg/L vollständig in 3,5-Diacetyl-1,4-dihydrolutidin (DDL- derivatisiert) sowohl für die Quarz- als auch für die Silizium-Fluidikzellen zu detektieren. Beide Systemewiesenein Abfragevolumen von 3,5 µL auf. Ein offensichtlich höheres Signal-Rausch-Verhältnis (SNR) wurde für die Silizium-Fluidzelle ($\text{SNR}_{\text{silicon}} = 6.1$) im Vergleich zur Quarz-Fluidzelle ($\text{SNR}_{\text{quartz}} = 4.9$) beobachtet. Die Verstärkung der Signalintensität in der Silizium-Fluidzelle ist wahrscheinlich auf den Silizium-Absorptionskoeffizienten bei der Anregungswellenlänge zurückzuführen,$a\left( \lambda_{\text{abs}} = 420\ nm \right) = 5 \bullet 10^{4}\text{cm}^{- 1}$. Dieser Koeffizient ist ungefähr fünfmal höher als der Absorptionskoeffizient bei der Fluoreszenzemissionswellenlänge $a\left(\lambda_{\text{em}} = 515\ nm \right) = 9.25 \bullet 10^{3}\text{cm}^{- 1}$. HCHO wird aufgrund seiner relativ hohen Konstanten für das Henry-Gesetz sehr schnell in ein flüssiges Reagenz aufgenommen. Somit hängt die Auswahl des molekularen Einfangverfahrens (Schwallströmung, Ringströmung oder membranbasierte Strömungswechselwirkung) von derLeistungsfähigkeit des Fluoreszenzdetektors ab. Ein vorläufiges Konzept, das auf der Verwendung einer Gas-Flüssigkeitsmembran-basierten Wechselwirkung zum ständigen Abfangen des gasförmigen HCHO basiert, wurde eingeführt. Hierzu wurden kompatible Materialien und Herstellungsmethoden identifiziert. Darüber hinaus wurden CFD-Simulationen durchgeführt, um die Mikrokanallänge unter verschiedenen hydrodynamischen Bedingungen abzuschätzen, die für eine vollständige HCHO-Derivatisierung erforderlich sind. Eine Verbesserung und Vereinfachung auf der Grundlage von sehrnempfindlichen Fluoreszenzdetektoren mit niedrigen Detektionsgrenzen könnte zukünftig basierend z. B. auf Schwallströmung oder Ringströmung möglich sein

Biosensors

A biosensor is defined as a detecting device that combines a transducer with a biologically sensitive and selective component. When a specific target molecule interacts with the biological component, a signal is produced, at transducer level, proportional to the concentration of the substance. Therefore biosensors can measure compounds present in the environment, chemical processes, food and human body at low cost if compared with traditional analytical techniques. This book covers a wide range of aspects and issues related to biosensor technology, bringing together researchers from 11 different countries. The book consists of 16 chapters written by 53 authors. The first four chapters describe several aspects of nanotechnology applied to biosensors. The subsequent section, including three chapters, is devoted to biosensor applications in the fields of drug discovery, diagnostics and bacteria detection. The principles behind optical biosensors and some of their application are discussed in chapters from 8 to 11. The last five chapters treat of microelectronics, interfacing circuits, signal transmission, biotelemetry and algorithms applied to biosensing

Investigation of Optical and Structural Properties of GeSn Heterostructures

Silicon (Si)-based optoelectronics have gained traction due to its primed versatility at developing light-based technologies. Si, however, features indirect bandgap characteristics and suffers relegated optical properties compared to its III-V counterparts. III-Vs have also been hybridized to Si platforms but the resulting technologies are expensive and incompatible with standard complementary-metal-oxide-semiconductor processes. Germanium (Ge), on the other hand, have been engineered to behave like direct bandgap material through tensile strain interventions but are well short of attaining extensive wavelength coverage. To create a competitive material that evades these challenges, transitional amounts of Sn can be incorporated into Ge matrix to form direct bandgap GeSn alloys that have led to the increasing possibility of engineering a suite of low-cost, light emission sources that applies to a wide range of infrared photonics and optoelectronics systems. Hence, the importance of studying the structural and optical properties of these GeSn heterostructures cannot be overemphasized. The first part of this dissertation investigates the structural and optical properties of SiGeSn/GeSn/SiGeSn quantum wells (QWs) where the photoluminescence (PL) behaviors of thick (22 nm in well) and thin (9 nm in well) GeSn QW samples are compared. Using PL results from two excitation lasers (532 nm and 1550 nm lasers) as well as studying their respective optical transitions, the result reveals that the thicker well sample shows i) a more direct bandgap outcome in addition to a much lower ground energy Г valley; ii) a higher carrier density within the well, and iii) an increased barrier height coupled with improved carrier confinement. All of these resulted in a significantly enhanced emission that allows for the first-ever estimation of GeSn QWs quantum efficiency (QE) while also suggesting a path towards efficient mid-infrared devices. To further improve the carrier confinement while also reducing the carrier leakage in the thicker well design, a SiGeSn/GeSn/GeSn/SiGeSn separate confinement heterostructure (SCH) is introduced. The sample is characterized and the optical properties are compared with the previously reported 9 nm and 22 nm well non-SCH samples. Based on the optical transition analysis, the SCH QW also shows significantly higher carrier confinement compared to reference samples. In addition to these studies, an attempt is made to investigate advanced quantum well structures through an all-inclusive structural and optical study of SiGeSn/GeSn/SiGeSn multi-quantum wells (MQWs). The resulting analysis shows evidence of intermixing diffusion during growth. The second part of this work provides insights into the behavior of annealed GeSn bulk samples near the indirect-to-direct transition point. The study attempts to provide connections between the strain, composition, and defect densities before and after annealing. The result reveals the impact of annealing on a sample may either i) lower the strain giving rise to an increased PL while reducing the energy separation or ii) introduce misfit dislocation/ surface roughness leading to an affected or decreased PL. Finally, this work also explores the low-temperature capability of our in-house plasma-enhanced ultra-high vacuum chemical vapor deposition system through the growth of Si-on-Ge epitaxy and pressure-dependent growth of GeSn bulk heterostructures

An analysis of MRAM based memory technologies

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2006.Includes bibliographical references (leaves 66-68).MRAM is a memory (RAM) technology that uses electron spin to store information. Often been called "the ideal memory", it can potentially combine the density of DRAM with the speed of SRAM and non-volatility of FLASH memory or hard disk, and all this while consuming a very low amount of power. However, it is the need for a fast and non-volatile computer memory that has been the key driver for evolution of this technology. At the moment, MRAM is in its final stages of development and much of the current research concentrates on issues like reducing the write current, increasing the density and making the process more reproducible. A lot of companies are pursuing research on this technology and are likely to introduce it into the market in the near future. However, it will be a while before MRAM can replace conventional memories. Nevertheless, since MRAM can resist high radiation, and can operate in extreme temperature conditions, it is likely that we will see the first MRAM in applications that need such properties.by Rangarajan Vijayaraghavan.M.Eng

Automated analysis of heterogeneous catalyst materials using deep learning

Heterogeneous catalyst materials play a key role in modern society, as many processes in the chemical and energy industry rely on them. Optimising their performance is directly connected to a large potential of reductions in energy consumption, and thus to a more sustainable future. A fundamental part in the optimisation process is represented by materials characterisation. This is often done using in situ (Scanning) Transmission Electron Microscopy ((S)TEM) imaging in order to obtain a full understanding of the catalyst performance in different environments and temperatures at high resolution. However, the analysis of corresponding dynamical datasets is often time-consuming and requires manual intervention alongside tailored post-processing routines. At the same time, the emergence of direct electron detectors allowing for the acquisition of datasets at kiloHertz frame rates, as well as novel imaging techniques raised data generation rates significantly and created a need for new, reliable and automated data processing techniques. This work introduces nNPipe as Deep Learning based method for the automated analysis of morphologically diverse heterogeneous catalyst systems. The method is based on two Covolutional Neural Networks (CNNs) that were exclusively trained on computationally generated HRTEM image simulations and allow for rapid and precise analysis of raw 2048 x 2048 experimental HRTEM images. The performance of nNPipe is demonstrated in a realistic automated imaging scenario where statistically significant material properties are inferred accurately. Moreover, time-efficient and reproducible retraining methods based small experimental datasets are described for both, further performance improvements and adaption to new imaging scenarios. In this context, a potentially new pathway for the generation of suitable training datasets obtained by thousands of mostly non-expert annotations is highlighted. Finally, the analytical capacities of the nNPipe method are showcased on time-resolved datasets in two advanced applications scenarios: i) Live image analysis during sample acquisition and ii) Analysis of the particle coalescence of an in situ heated Pd/C catalyst