A Kinetic and Mechanistic Study of the Chemical Vapor Deposition of Titanium Dioxide Using Alkoxide Precursors PDF Download

Author: Carl Pete Fictorie
Publisher:
ISBN:
Category :
Languages : en
Pages : 494

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Author: Polly Wanda Chu
Publisher:
ISBN:
Category :
Languages : en
Pages : 434

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Thin titanium dioxide films were produced by metalorganic chemical vapor deposition on sapphire(0001) in an ultrahigh vacuum (UHV) chamber. A method was developed for producing controlled submonolayer depositions from titanium isopropoxide precursor. Film thickness ranged from 0.1 to 2.7 nm. In situ X-ray photoelectron spectroscopy (XPS) was used to determine film stoichiometry with increasing thickness. The effect of isothermal annealing on desorption was evaluated. Photoelectron peak shapes and positions from the initial monolayers were analyzed for evidence of interface reaction. Deposition from titanium isopropoxide is divided into two regimes: depositions below and above the pyrolysis temperature. This temperature was determined to be 300 deg C. Controlled submonolayers of titanium oxide were produced by cycles of dosing with titanium isopropoxide vapor below and annealing above 300 deg C. Precursor adsorption below the pyrolysis temperature was observed to saturate after 15 minutes of dosing. The quantity absorbed was shown to have an upper limit of one monolayer. The stoichiometry of thin films grown by the cycling method were determined to be TiO2. Titanium dioxide film stoichiometry was unaffected by isothermal annealing at 700 deg C. Annealing produced a decrease in film thickness. This was explained as due to desorption. Desorption ceased at approximately 2.5 to 3 monolayers, suggesting bonding of the initial monolayers of film to sapphire is stronger than to itself. Evidence of sapphire reduction at the interface by the depositions was not observed. The XPS O is peak shifted with increased film thickness. The shifts were consistent with oxygen in sapphire and titanium dioxide having different O is photoelectron peak positions. Simulations showed the total shifts for thin films ranging in thickness of 0.1 to 2.7 nm to be -0.99 to -1.23 eV. Thick films were produced for comparison.

Author: Elizabeth Larson Crane
Publisher:
ISBN:
Category :
Languages : en
Pages : 336

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Author: Michel Houssa
Publisher: CRC Press
ISBN: 1420034146
Category : Science
Languages : en
Pages : 614

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The drive toward smaller and smaller electronic componentry has huge implications for the materials currently being used. As quantum mechanical effects begin to dominate, conventional materials will be unable to function at scales much smaller than those in current use. For this reason, new materials with higher electrical permittivity will be requ

Author: Jinwoo Cheon
Publisher:
ISBN:
Category :
Languages : en
Pages : 302

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Category : Dissertations, Academic
Languages : en
Pages : 806

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Category : Dissertation abstracts
Languages : en
Pages : 784

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Author: Hugh O. Pierson
Publisher: William Andrew
ISBN: 1437744885
Category : Technology & Engineering
Languages : en
Pages : 458

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Book Description
Handbook of Chemical Vapor Deposition: Principles, Technology and Applications provides information pertinent to the fundamental aspects of chemical vapor deposition. This book discusses the applications of chemical vapor deposition, which is a relatively flexible technology that can accommodate many variations. Organized into 12 chapters, this book begins with an overview of the theoretical examination of the chemical vapor deposition process. This text then describes the major chemical reactions and reviews the chemical vapor deposition systems and equipment used in research and production. Other chapters consider the materials deposited by chemical vapor deposition. This book discusses as well the potential applications of chemical vapor deposition in semiconductors and electronics. The final chapter deals with ion implantation as a major process in the fabrication of semiconductors. This book is a valuable resource for scientists, engineers, and students. Production and marketing managers and suppliers of equipment, materials, and services will also find this book useful.

Author: Rungthiwa Methaapanon
Publisher:
ISBN:
Category :
Languages : en
Pages :

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The demand of smaller, higher capacity and higher performance devices in microelectronics has driven the necessity of uniform, conformal, and pinhole-free thin film production. Furthermore, the design toward more complex structures and higher aspect ratios requires the processes to be highly controllable, down to the nanoscale. Atomic layer deposition (ALD) is a powerful technique that produces thin films with these desired properties, through a series of alternating self-limited surface reactions. The self-saturated nature of the technique allows for precise thickness control at the atomic scale. Despite increasing interest in ALD, there is still a lack of understanding of the mechanisms behind the process at a molecular level. The nucleation and growth fundamentals are crucial for better control and development of the process and, hence, need to be systematically studied. Due to the vulnerability of the reactions to ambient conditions, ex situ analysis techniques alone may not provide complete information on the surface chemistries needed to elucidate the mechanisms governing the processes. In situ analysis techniques, which allow surface investigation without disruption from contaminants and other species, are required. Therefore, in this work we have designed and constructed various in situ systems for this purpose. The in situ systems are ALD reactors integrated with different analysis tools, able to operate as fully functional deposition system so as to replicate the actual conditions of typical ALD reactors. Through in situ X-ray photoelectron spectroscopy (XPS), we studied ALD of TiO2 at 100 °C using titanium tetrachloride (TiCl4) and water (H2O) on two different surfaces. The initial growth rate on hydroxyl-enriched silicon dioxide (SiO2) is found to be higher than on hydrogen-terminated silicon. The XPS results provide evidence of Si-O-Ti bonds on the SiO2 surface and Si-Ti bonds on the hydrogen-terminated Si surface, without a trace of interfacial oxide. However, a silicon oxide layer forms at the interface between Si and TiO2 after vacuum annealing, concurrent with the reduction of TiO2. The results hence suggest TiO2 as an oxygen source for silicon oxidation under these conditions. In addition, we studied ruthenium thermal ALD using a new precursor, bis(2,4-dimethylpentadienyl) ruthenium, and oxygen. The process is achievable at a low operating temperature of 185 °C. Variation in the exposure time and pressure of oxygen has significant effects on the nucleation, growth rate and composition of the deposited ruthenium films. We propose that the subsurface oxygen formation, which involves slow diffusion of oxygen, is a rate-limiting step in the RuO2 formation process. The crystal growth and structures of Ru and RuO2 deposited on amorphous SiO2 by the same ALD process were measured by ex situ and in situ synchrotron X-ray diffraction. Interestingly, in situ XRD studies reveal that RuO2 films initially nucleate as metallic Ru crystallites. The hindered formation of subsurface oxygen in small nanocrystals is hypothesized as the cause that prohibits the growth of the initial oxide. Although metallic ruthenium films are textured with a (002) preference in the growth direction, RuO2 films nucleating on the metallic Ru nanoparticles have no preferential orientation. We also studied surface chemistries of Ru reactions during half ALD cycles via in situ synchrotron photoemission spectroscopy (PES). After long oxygen exposures, Ru oxide and carbon-oxygen species, which localize near the top surface, were detected. The peak intensities of these species noticeably decreased after reaction with the Ru precursor, indicating the reactions of Ru precursor with both O-Ru and O-C species. In brief, we fabricated and utilized in situ ALD/analysis systems, together with ex situ analysis tools, for studies of TiO2 ALD and Ru/RuO2 ALD. The studies not only demonstrate the power of the in situ systems for mechanistic studies, but also provide information on possible bond formation, surface reactions, and nucleation and growth mechanisms in the ALD processes.

Author: Gertjan Koster
Publisher: Woodhead Publishing
ISBN: 0081029462
Category : Science
Languages : en
Pages : 534

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Epitaxial Growth of Complex Metal Oxides, Second Edition reviews techniques and recent developments in the fabrication quality of complex metal oxides, which are facilitating advances in electronic, magnetic and optical applications. Sections review the key techniques involved in the epitaxial growth of complex metal oxides and explore the effects of strain and stoichiometry on crystal structure and related properties in thin film oxides. Finally, the book concludes by discussing selected examples of important applications of complex metal oxide thin films, including optoelectronics, batteries, spintronics and neuromorphic applications. This new edition has been fully updated, with brand new chapters on topics such as atomic layer deposition, interfaces, STEM-EELs, and the epitaxial growth of multiferroics, ferroelectrics and nanocomposites. Examines the techniques used in epitaxial thin film growth for complex oxides, including atomic layer deposition, sputtering techniques, molecular beam epitaxy, and chemical solution deposition techniques Reviews materials design strategies and materials property analysis methods, including the impacts of defects, strain, interfaces and stoichiometry Describes key applications of epitaxially grown metal oxides, including optoelectronics, batteries, spintronics and neuromorphic applications