1,721,123 research outputs found
Theoretical examination of thermo-migration in novel platinum microheaters
Full text linkConductometric gas sensors based on SMO films must be heated to temperatures up to 550 °C in order to initiate the molecular adsorption process at the SMO film's surface. Very often platinum is used as the microheater material. The long-term reliability of these devices are primarily associated with the mechanical stability of the micro-electro-mechanical systems (MEMS) structures used to hold the microheater suspended and thermally isolated from other integrated components, such as analog and digital circuitry. However, previous studies have shown that that electro-migration and thermo-migration phenomena could potentially exacerbate the stress build-up in platinum microheaters and contribute to their eventual failure. In this manuscript we propose a means to quantify the impact of vacancy transport on stress build-up in two novel microheater designs under electro-migration and thermo-migration phenomena. The first design is aimed at improved temperature uniformity and the second is aimed at microheater array operation, taking advantage of high temperature gradients to simultaneously provide multiple temperatures at different sensor locations. Our analysis shows that the thermo-migration force is much higher than the electro-migration force, meaning that the high thermal gradients in these devices contribute far more to vacancy transport than the atom transport induced by the electron wind. Furthermore, we calculate that our proposed designs are highly resistant to failure due to vacancy migration by calculating the mean-time-to-failure to be on the order of 1015 seconds under typical operating conditions
Miniaturized Transistors, Volume II
No full textDue to the great success of the initial Special Issue on Miniaturized Transistors, we have decided to continue addressing the ever-advancing progress in microelectronic device scaling with this second volume. Complementary Metal-Oxide-Semiconductor (CMOS) devices continue to endure miniaturization, irrespective of seeming physical limitations to scaling, helped by advancing fabrication techniques. We also observe that miniaturization does not always refer to the latest technology node for digital transistors. Rather, by applying novel materials and device geometries, we note that a significant reduction in the size of microelectronic devices for a broad set of applications can be achieved. The achievements made in the scaling of devices for applications beyond digital logic (e.g., power applications, optoelectronics, and sensors) are taking the front stage in microelectronic miniaturization. Furthermore, all these achievements are assisted by improvements in the simulation and modeling of the involved materials and device structures. In particular, process and device technology computer-aided design (TCAD) has become indispensable in the design cycle of novel devices and technologie
Miniaturized Transistors, Volume II
No full textIn this book, we aim to address the ever-advancing progress in microelectronic device scaling. Complementary Metal-Oxide-Semiconductor (CMOS) devices continue to endure miniaturization, irrespective of the seeming physical limitations, helped by advancing fabrication techniques. We observe that miniaturization does not always refer to the latest technology node for digital transistors. Rather, by applying novel materials and device geometries, a significant reduction in the size of microelectronic devices for a broad set of applications can be achieved. The achievements made in the scaling of devices for applications beyond digital logic (e.g., high power, optoelectronics, and sensors) are taking the forefront in microelectronic miniaturization. Furthermore, all these achievements are assisted by improvements in the simulation and modeling of the involved materials and device structures. In particular, process and device technology computer-aided design (TCAD) has become indispensable in the design cycle of novel devices and technologies. It is our sincere hope that the results provided in this Special Issue prove useful to scientists and engineers who find themselves at the forefront of this rapidly evolving and broadening field. Now, more than ever, it is essential to look for solutions to find the next disrupting technologies which will allow for transistor miniaturization well beyond silicon’s physical limits and the current state-of-the-art. This requires a broad attack, including studies of novel and innovative designs as well as emerging materials which are becoming more application-specific than ever before
Accelerating Flux Calculations Using Sparse Sampling
Full text linkThe ongoing miniaturization in electronics poses various challenges in the designing of modern devices and also in the development and optimization of the corresponding fabrication processes. Computer simulations offer a cost- and time-saving possibility to investigate and optimize these fabrication processes. However, modern device designs require complex three-dimensional shapes, which significantly increases the computational complexity. For instance, in high-resolution topography simulations of etching and deposition, the evaluation of the particle flux on the substrate surface has to be re-evaluated in each timestep. This re-evaluation dominates the overall runtime of a simulation. To overcome this bottleneck, we introduce a method to enhance the performance of the re-evaluation step by calculating the particle flux only on a subset of the surface elements. This subset is selected using an advanced multi-material iterative partitioning scheme, taking local flux differences as well as geometrical variations into account. We show the applicability of our approach using an etching simulation of a dielectric layer embedded in a multi-material stack. We obtain speedups ranging from 1.8 to 8.0, with surface deviations being below two grid cells (0.6⁻3% of the size of the etched feature) for all tested configurations, both underlining the feasibility of our approach
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
A Method for Simulating the Influence of Grain Boundaries and Material Interfaces on Electromigration
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