1,720,956 research outputs found
Suspended Gate Silicon Nanodot Memory
No full textThe non-volatile memory market has been driven by Flash memory since its invention more than three decades ago. Today, this non-volatile memory is used in a wide variety of devices and systems from pen drives, mp3 players to cars, planes and satellites. However,the conventional floating gate memory technology in use for flash memory is facing a serious scalability issue, the tunnel oxide thickness cannot be reduced to less than 7nm as pointed out in the latest international technology roadmap for semiconductors (ITRS2010) [1]. The limit imposed on the tunnel oxide layer reduces the programming and erasing times, the scalability and endurance among other parameters. To overcome those inherent issues, this research is focused on the co-integration of nano-electromechanical systems (NEMS) with metal-oxide-semiconductor (MOS) technology in order to generate a new non-volatile and high speed memory. The memory device that we are proposing is a high-speed non-volatile memory structure called the Suspended Gate Silicon Nanodot Memory (SGSNM) cell. This non-volatile memory device features a MOSFET as a readout element, a silicon nanodot (SiNDs) monolayer as the floating gate and a movable suspended control gate isolated from the floating gate by an oxide layer and by an air-gap. The fundamental component in this novel device is the introduction of a doubly-clamped beam as a movable control gate, in which through this element, the programming and erasing operations take place. To understand the behaviour of the doubly-clamped beam structure, it is analysed by using analytical models such as the doubly-plate capacitor model and also by using two- and three-dimensional (2D and 3D) finite element method (FEM) analysis. The programming and erasing operations within the SGSNM occur when the suspended control gate is in contact with the tunnel oxide layer. This is the point at which the quantum-mechanical tunnelling mechanism (Fowler-Nordheim) takes place. Through this mechanism, the electrons are allowed to tunnel from the suspended control gate into the memory node and vice versa as a function of the applied voltage (bias). The tunnelling process is numerically analysed by implementing the Tsu-Esaki equation and the transfer matrix method within a homemade program which calculates the current density as a function of the tunnel oxide material and thickness. Both the suspended control gate and tunnelling process are implemented as analog behavioural models within the SGSNM cell that is simulated by using a commercial circuit simulator. From a transient analysis of the suspended control gate, it was found that the suspended control gate takes 0.8 nsec in pull-in on the tunnel oxide layer for a 1 ?m-long doubly-clamped structure. In contrast, the time that the memory node takes in charge and discharge is 1.7 nsec. Hence, the programming and erasing times are a combination between the mechanical pull-in and the charging time, which is 2.5 nsec due the fact that to both operations are symmetrical. Moreover, the suspended control gate was successfully fabricated and suspended. This process was performed by depositing a thin layer of aluminium (500 nm) over the sacrificial layer (poly-Si) by using an e-beam evaporator, which was patterned with doubly-clamped beam features through the photolithographic process. By using a combination of wet and dry etching processes, the aluminium and the sacrificial layer were successfully removed without affecting the substrate (Si-based) or the suspended control gate beam. In addition, Capacitance - Voltage measurements were performed on a set of doubly-clamped beams from which the pull-in effect was successfully obtained. Finally, the footprints for the memory device fabrication process were developed and sketched within the document as well as the design of three photomask
Fabrication and characterisation of a double-clamped beam structure as a control gate for a high-speed non-volatile memory device
No full textWe report the fabrication and characterisation of a suspended double-clamped beam structure that is implemented as a movable control gate within a hybrid high-speed non-volatile memory device. This structure features a foundation of SiO2/Si layers over which a poly-Si layer (sacrificial) is deposited by using a low-pressure chemical vapour deposition (LPCVD) and as a movable control gate, an aluminium (Al) layer is deposited by using an e-beam evaporator. The Al layer is patterned with double-clamped beam structures by using photolithography and through a combination of wet and dry etching processes, the structures are successfully suspended and characterised by using a C–V meter. From the structure characterisation, the pull-in curve is successfully obtained and due to unexpected large short-range forces such as the van der Waals forces, the pull-out curve is not observed. In order to clarify this issue, a numerical analysis is performed in which the structural materials under test shown the influence of such short-range forces on the structure and a solution to override them is propose
NEMS-MOS and NEMS-SET hybrid functional systems for advanced information processing and extreme sensing
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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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