Download or read book Modelling of Czochralski Crystal Growth for Advanced Control Design written by Danielle Andrea Wilson and published by . This book was released on 2002 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modeling Dynamics and Control of the Czochralski Crystal Growth Process written by Ning Duanmu and published by . This book was released on 2006 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Czochralski crystal growth is a widely used technology for manufacturing semiconductor crystals. Currently, semiconductor manufacturers desire to increase the crystal diameter in order to minimize the unit cost per chip during wafer processing while also reducing dislocation density and micro defect level in order to fabricate circuits with decreasing line widths. However, the ability to meet these advanced manufacturing objectives is limited by the current process control architecture since it has not been explicitly designed to deal with important process complexities including the nonlinear and time varying dynamics and cross coupled physics. In order to design a better control system, a process model is developed to reflect the real equipment features of commercial scale Czochralski crystal growth furnaces and capture the fundamental process physics governed by heat and mass transport processes. The model is used to study the system dynamic characteristics and input-output relations in order to develop an improved control structure and control algorithm.
Download or read book Modeling and Control of the Czochralski Crystal Growth Process written by Denise Marie Martinez and published by . This book was released on 2001 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Analysis of the Czochralski Crystal Growth Models Designated for Optimal Control written by Irena Pawłow and published by . This book was released on 1995 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Integrated Intelligent Modeling Design and Control of Crystal Growth Processes written by and published by . This book was released on 2000 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Growth of single crystals is the critical beginning step for electronic, opto-electronic, MEMS and many other devices. This MURI program took an integrated approach towards modeling, design and control of crystal growth processes and in conjunction with growth and characterization experiments developed much better understanding of growth phenomena and materials defects. It led to the development of most comprehensive and accurate models that account for conduction, convection and volumetric, spectral radiation heat transfer, oscillatory and turbulent flows, transport and segregation of dopants and impurities, phase change, an applied magnetic and/or electric field, and generation and multiplication of crystal defects. Using state-of-the-art adaptive grid generation techniques and parallel algorithms, the models can perform three-dimensional, dynamic simulations. While establishing white beam x-ray topography as the leading technique for crystal characterization, this research led to many new theories for grow the behavior and defects. Advanced model-based control algorithms were developed for in-situ synthesis and Czochralski growth. Notable among many successful technology transfer projects are: AFRL-developed one-step in-situ synthesis and growth of indium phosphide crystals, growth of large diameter silicon carbide crystals, 500 mm diameter silicon tube growth, transport model for hydrothermal growth, wire saw technology and high yield polysilicon production. Besides involving numerous faculty, the project succeeded in training a large number of postdoctoral fellows and undergraduate and graduate students in crystal growth.
Download or read book Simulation of a Feedback Control System for Czochralski Crystal Growth written by Cédric Westphal and published by . This book was released on 1995 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Crystal Growth Processes Based on Capillarity written by Thierry Duffar and published by John Wiley & Sons. This book was released on 2010-03-30 with total page 566 pages. Available in PDF, EPUB and Kindle. Book excerpt: Crystal Growth Processes Based on Capillarity closely examines crystal growth technologies, like Czochralski, Floating zone, and Bridgman. The up-to-date reference contains detailed technical and applied information, especially on the difficulty of crystal shape control. Including practical examples and software applications, this book provides both theoretical and experimental sections. Edited by a well-respected academic with over twenty-five years of experience in this field, the text is an excellent resource for professionals in crystal growth as well as for students in understanding the fundamentals and the technology of crystal growth.
Download or read book Delay Modeling and Long range Predictive Control of Czochralski Growth Process written by Dhaval Shah and published by . This book was released on 2009 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work presents the Czochralski growth dynamics as time-varying delay based model, applied to the growth of La3Ga5.5Ta0.5O14 (LGT) piezoelectric crystals. The growth of high-quality large-diameter oxides by Czochralski technique requires the theoretical understanding and optimization of all relevant process parameters, growth conditions, and melts chemistry. Presently, proportional-integral- derivative (PID) type controllers are widely accepted for constant-diameter crystal growth by Czochralski. Such control systems, however, do not account for aspects such as the transportation delay of the heat from crucible wall to the crystal solidification front, heat radiated from the crucible wall above the melt surface, and varying melt level. During crystal growth, these time delays play a dominant role, and pose a significant challenge to the control design. In this study, a time varying linear delay model was applied to the identification of nonlinearities of the growth dynamics. Initial results reveled the benefits of this model with actual growth results. These results were used to develop a long-range model predictive control system design. Two different control techniques using long range prediction are studied for the comparative study. Development and testing of the new control system on real time growth system are discussed in detail. The results are promising and suggest future work in this direction. Other discussion about the problems during the crystal growth, optimization of crystal growth parameters are also studied along with the control system design.
Download or read book Student Augmentation for Crystal Growth Research written by and published by . This book was released on 1999 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Three graduate students and one undergraduate student were supported to pursue research in the area of crystal growth and complement the research activities of AFOSR/DARPA MURI project on integrated intelligent modeling, design and control of crystal growth processes. One doctoral student worked on integrating the radiation heat transfer model into MASTRAPP, the crystal growth model developed by the Consortium for Crystal Growth Research. He also built a parallel processing algorithm. The other two Masters and one undergraduate students worked in the area of experimental methods to develop database for model validation. These students have developed a three-dimensional temperature field visualization technique using liquid crystals as tracers and digital imaging software for 3D reconstruction. Reconstruction of 3D field from a series of 2D images is a novel technique and can be used for flow and heat transfer analysis that is inherently three-dimensional and oscillatory, e.g., melt flow in Czochralski crystal growth.
Download or read book Crystal Growth from the Melt written by Georg Müller and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 145 pages. Available in PDF, EPUB and Kindle. Book excerpt: 1 The content ofthis article is based on a German book version ) which appeared at the end of the year 1986. The author tried to incorporate - as far as possible - new important results published in the last year. But the literature in the field of "convection and inhomogeneities in crystal growth from the melt" has increased so much in the meantime that the reader and the collegues should make allowance for any incompleteness, also in the case that their important contributions have not been cited. This could for example hold for problems related to the Czochralski growth. But especially for this topic the reader may be refered to the forthcoming volume of this series, which contains special contributions on "Surface Tension Driven Flow in Crystal Growth Melts" by D. Schwabe and on "Convection in Czochralski Melts" by M. Mihelcic, W. Uelhoff, H. Wenzl and K. Wingerath. The preparation of this manuscript has been supported by several women whose help is gratefully acknowledged by the autor: Mrs. Gisela Neuner for the type writing, Mrs. Abigail Sanders, Mrs. Fiona Eels and especially Prof. Nancy Haegel for their help in questions of the English language and Mrs. Christa Weber for reading corrections. Also the good cooperation with the Springer Verlag, especially Mrs. Bohlen and with the managing editor of Crystals, Prof. H. C. Freyhardt, who critically read the manuscript, is acknowledged.
Download or read book Handbook of Crystal Growth written by Tatau Nishinaga and published by . This book was released on 1994 with total page 755 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Crystal Growth Technology written by Hans J. Scheel and published by John Wiley & Sons. This book was released on 2011-09-22 with total page 521 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book top experts treat general thermodynamic aspects of crystal fabrication; numerical simulation of industrial growth processes; commercial production of bulk silicon, compound semiconductors, scintillation and oxide crystals; X-ray characterization; and crystal machining. Also, the role of crystal technology for renewable energy and for saving energy is discussed. It will be useful for scientists and engineers involved in crystal and epilayer fabrication as well as for teachers and graduate students in material science, chemical and metallurgical engineering, and micro- and optoelectronics, including nanotechnology.
Download or read book Handbook of Crystal Growth written by Peter Rudolph and published by Elsevier. This book was released on 2014-11-04 with total page 1420 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vol 2A: Basic TechnologiesHandbook of Crystal Growth, Second Edition Volume IIA (Basic Technologies) presents basic growth technologies and modern crystal cutting methods. Particularly, the methodical fundamentals and development of technology in the field of bulk crystallization on both industrial and research scales are explored. After an introductory chapter on the formation of minerals, ruling historically the basic crystal formation parameters, advanced basic technologies from melt, solution, and vapour being applied for research and production of the today most important materials, like silicon, semiconductor compounds and oxides are presented in detail. The interdisciplinary and general importance of crystal growth for human live are illustrated.Vol 2B: Growth Mechanisms and DynamicsHandbook of Crystal Growth, Second Edition Volume IIB (Growth Mechanisms and Dynamics) deals with characteristic mechanisms and dynamics accompanying each bulk crystal growth method discussed in Volume IIA. Before the atoms or molecules pass over from a position in the fluid medium (gas, melt or solution) to their place in the crystalline face they must be transported in the fluid over macroscopic distances by diffusion, buoyancy-driven convection, surface-tension-driven convection, and forced convection (rotation, acceleration, vibration, magnetic mixing). Further, the heat of fusion and the part carried by the species on their way to the crystal by conductive and convective transport must be dissipated in the solid phase by well-organized thermal conduction and radiation to maintain a stable propagating interface. Additionally, segregation and capillary phenomena play a decisional role for chemical composition and crystal shaping, respectively. Today, the increase of high-quality crystal yield, its size enlargement and reproducibility are imperative conditions to match the strong economy.Volume 2A - Presents the status and future of Czochralski and float zone growth of dislocation-free silicon - Examines directional solidification of silicon ingots for photovoltaics, vertical gradient freeze of GaAs, CdTe for HF electronics and IR imaging as well as antiferromagnetic compounds and super alloys for turbine blades - Focuses on growth of dielectric and conducting oxide crystals for lasers and non-linear optics - Topics on hydrothermal, flux and vapour phase growth of III-nitrides, silicon carbide and diamond are explored Volume 2B - Explores capillarity control of the crystal shape at the growth from the melt - Highlights modeling of heat and mass transport dynamics - Discusses control of convective melt processes by magnetic fields and vibration measures - Includes imperative information on the segregation phenomenon and validation of compositional homogeneity - Examines crystal defect generation mechanisms and their controllability - Illustrates proper automation modes for ensuring constant crystal growth process - Exhibits fundamentals of solution growth, gel growth of protein crystals, growth of superconductor materials and mass crystallization for food and pharmaceutical industries
Download or read book The Modeling Simulation and Control of Transport Phenomena in a Thermally Destabilizing Bridgman Crystal Growth System written by Paul Julio Sonda and published by . This book was released on 2003 with total page 520 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bulk Crystal Growth written by D. T. J. Hurle and published by Elsevier. This book was released on 2016-06-06 with total page 671 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volume 2 is divided into 2 parts. Part A reviews the principal techniques used for bulk single crystal growth from melt, solution and vapour and for industrial mass crystallisation starting, in chapter 1, with nature's techniques. The growth of synthetic crystals of a wide range of materials for research and commercial use is covered in depth, with emphasis placed on those techniques which are of current importance: techniques of only historical interest have not been included. Part B covers the basic mechanisms and dynamics of melt and solution growth covering segregation, melt convection, stress in the cooling crystal, polyphase solidification, growth in gels, spherulitic crystallisation and the numerical modelling of Bridgman and Czochralski growth processes.
Download or read book Nonlinear Modelling and Control of Czochralski Crystal written by Abdellah Mokhtari and published by . This book was released on 1988 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Segregation and Shape Control in Czochralski Crystal Growth written by Ming-Hsien Lin and published by . This book was released on 1995 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt:
