Multi Scale Modeling Of Chemical Vapor Deposition

Multi-scale modeling of chemical vapor deposition (CVD) is a very broad topic because a large number of physical processes affect the quality and speed of film deposition. These processes have different length scales associated with them creating the need for a multi-scale model. The three main scales of importance to the modeling of CVD are the reactor scale, the feature scale, and the atomic scale. The reactor scale ranges from meters to millimeters and is called the reactor scale because it corresponds with the scale of the reactor geometry. The micrometer scale is labeled as the feature scale in this study because this is the scale related to the feature geometries. However, this is also the scale at which grain boundaries and surface quality can be discussed. The final scale of importance to the CVD process is the atomic scale. The focus of this study is on the reactor and feature scales with special focus on the coupling between these two scales. Currently there are two main methods of coupling between the reactor and feature scales. The first method is mainly applied when a modified line of sight feature scale model is used, with coupling occurring through a mass balance performed at the wafer surface. The second method is only applicable to Monte Carlo based feature scale models. Coupling in this second method is accomplished through a mass balance performed at a plane offset from the surface.

(Cont.) In order to model selective epitaxy, the mask is represented as a hard wall boundary condition, and overgrowth on (111)A facets is included. With this model, we investigate the effects of the unknown parameters and the growth conditions on film morphology evolution. The observed trends are in agreement with the experimental data. Since KMC simulations are limited to small surfaces and short deposition times we propose algorithms for linking the KMC and mesoscale feature shape evolution models. Finally, the feasibility of linking the coupled KMC-mesoscale model and the reactor or reactor-feature scale models is assessed.

This book offers a timely and complete overview on chemical vapour deposition (CVD) and its variants for the processing of nanoparticles, nanowires, nanotubes, nanocomposite coatings, thin and thick films, and composites. Chapters discuss key aspects, from processing, material structure and properties to practical use, cost considerations, versatility, and sustainability. The author presents a comprehensive overview of CVD and its potential in producing high performance, cost-effective nanomaterials and thin and thick films. Features Provides an up-to-date introduction to CVD technology for the fabrication of nanomaterials, nanostructured films, and composite coatings Discusses processing, structure, functionalization, properties, and use in clean energy, engineering, and biomedical grand challenges Covers thin and thick films and composites Compares CVD with other processing techniques in terms of structure/properties, cost, versatility, and sustainability Kwang-Leong Choy is the Director of the UCL Centre for Materials Discovery and Professor of Materials Discovery in the Institute for Materials Discovery at the University College London. She earned her D.Phil. from the University of Oxford, and is the recipient of numerous honors including the Hetherington Prize, Oxford Metallurgical Society Award, and Grunfeld Medal and Prize from the Institute of Materials (UK). She is an elected fellow of the Institute of Materials, Minerals and Mining, and the Royal Society of Chemistry.

Semiconductor equipment modeling has in recent years become a field of great interest, because it offers the potential to support development and optimization of manufacturing equipment and hence reduce the cost and improve the quality of the reactors. This book is the result of two parallel lines of research dealing with the same subject - Modeling of Tungsten CVD processes -, which were per formed independently under very different boundary conditions. On the one side, Chris Kleijn, working in an academic research environment, was able to go deep enough into the subject to laya solid foundation and prove the validity of all the assumptions made in his work. On the other side, Christoph Werner, working in the context of an industrial research lab, was able to closely interact with manufacturing and development engineers in a modern submicron semiconductor processing line. Because of these different approaches, the informal collaboration during the course of the projects proved to be extremely helpful to both sides, even though - or perhaps because - different computer codes, different CVD reactors and also slightly different models were used. In spite of the inconsistencies which might arise from this double approach, we feel that the presentation of both sets of results in one book will be very useful for people working in similar projects.

IMA Volumes 135: Transport in Transition Regimes and 136: Dispersive Transport Equations and Multiscale Models focus on the modeling of processes for which transport is one of the most complicated components. This includes processes that involve a wdie range of length scales over different spatio-temporal regions of the problem, ranging from the order of mean-free paths to many times this scale. Consequently, effective modeling techniques require different transport models in each region. The first issue is that of finding efficient simulations techniques, since a fully resolved kinetic simulation is often impractical. One therefore develops homogenization, stochastic, or moment based subgrid models. Another issue is to quantify the discrepancy between macroscopic models and the underlying kinetic description, especially when dispersive effects become macroscopic, for example due to quantum effects in semiconductors and superfluids. These two volumes address these questions in relation to a wide variety of application areas, such as semiconductors, plasmas, fluids, chemically reactive gases, etc.

Multiscale Modeling for Process Safety Applications is a new reference demonstrating the implementation of multiscale modeling techniques on process safety applications. It is a valuable resource for readers interested in theoretical simulations and/or computer simulations of hazardous scenarios. As multi-scale modeling is a computational technique for solving problems involving multiple scales, such as how a flammable vapor cloud might behave if ignited, this book provides information on the fundamental topics of toxic, fire, and air explosion modeling, as well as modeling jet and pool fires using computational fluid dynamics. The book goes on to cover nanomaterial toxicity, QPSR analysis on relation of chemical structure to flash point, molecular structure and burning velocity, first principle studies of reactive chemicals, water and air reactive chemicals, and dust explosions. Chemical and process safety professionals, as well as faculty and graduate researchers, will benefit from the detailed coverage provided in this book. Provides the only comprehensive source addressing the use of multiscale modeling in the context of process safety Bridges multiscale modeling with process safety, enabling the reader to understand mapping between problem detail and effective usage of resources Presents an overall picture of addressing safety problems in all levels of modeling and the latest approaches to each in the field Features worked out examples, case studies, and a question bank to aid understanding and involvement for the reader

This book—the first of its kind—presents general methods for feedback controller synthesis and optimization of multiscale systems, illustrating their application to thin-film growth, sputtering processes, and catalytic systems of industrial interest. The authors demonstrate the advantages of the methods presented for control and optimization through extensive simulations. Included in the work are new techniques for feedback controller design and optimization of multiscale process systems that are not included in other books. The book also contains a rich collection of new research topics and references to significant recent work.