An Examination of Precursor Chemistry and Its Effect on Microstructure Development in Chemical Vapor Deposition of Titanium Dioxide and Aluminum Thin Films

An Examination of Precursor Chemistry and Its Effect on Microstructure Development in Chemical Vapor Deposition of Titanium Dioxide and Aluminum Thin Films PDF Author: Charles John Taylor
Publisher:
ISBN:
Category :
Languages : en
Pages : 314

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Precursor Chemistry of Advanced Materials

Precursor Chemistry of Advanced Materials PDF Author: Roland A. Fischer
Publisher: Springer Science & Business Media
ISBN: 9783540016052
Category : Science
Languages : en
Pages : 240

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Material synthesis by the transformation of organometallic compounds (precursors) by vapor deposition techniques such as chemical vapor deposition (CVD) and atomic layer deposition (ALD) has been in the forefront of modern day research and development of new materials. There exists a need for new routes for designing and synthesizing new precursors as well as the application of established molecular precursors to derive tuneable materials for technological demands. With regard to the precursor chemistry, a most detailed understanding of the mechanistic complexity of materials formation from molecular precursors is very important for further development of new processes and advanced materials. To emphasize and stimulate research in these areas, this volume comprises a selection of case studies covering various key-aspects of the interplay of precursor chemistry with the process conditions of materials formation, particularly looking at the similarities and differences of CVD, ALD and nanoparticle synthesis, e.g. colloid chemistry, involving tailored molecular precursors.

Ultrahigh Vacuum Metalorganic Chemical Vapor Deposition and in Situ Characterization of Nanoscale Titanium Dioxide Films

Ultrahigh Vacuum Metalorganic Chemical Vapor Deposition and in Situ Characterization of Nanoscale Titanium Dioxide Films PDF 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.

The Chemical Vapor Deposition of Zirconium Dioxide from Zirconium Tetra-tert-butoxide and Zirconium Nitrate

The Chemical Vapor Deposition of Zirconium Dioxide from Zirconium Tetra-tert-butoxide and Zirconium Nitrate PDF Author: David Jeffrey Burleson
Publisher:
ISBN:
Category :
Languages : en
Pages : 438

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Dissertation Abstracts International

Dissertation Abstracts International PDF Author:
Publisher:
ISBN:
Category : Dissertations, Academic
Languages : en
Pages : 856

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Directory of Graduate Research

Directory of Graduate Research PDF Author:
Publisher:
ISBN:
Category : Chemistry
Languages : en
Pages : 1846

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Faculties, publications and doctoral theses in departments or divisions of chemistry, chemical engineering, biochemistry and pharmaceutical and/or medicinal chemistry at universities in the United States and Canada.

Thermal and Dynamic Processes in Deposition, Growth, and Etching of Materials

Thermal and Dynamic Processes in Deposition, Growth, and Etching of Materials PDF Author: Shrikant Prabhakar Lohokare
Publisher:
ISBN:
Category :
Languages : en
Pages : 574

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Chemical vapor deposition (CVD) is becoming an increasingly important manufacturing process for the fabrication of VLSI and ULSI devices. A major challenge in optimizing a CVD process is developing an understanding of the complex mechanistic pathways followed. The first section in this thesis reports studies on the thermal and dynamical activation of surface bound alkyl species which play a vital role in the form of intermediates in metal-organic chemical vapor deposition. The particular systems of interest are those of aluminum CVD precursors. Models of these intermediates are obtained by thermal decomposition of alkyl iodides. The results provide an insight into the complex reaction patterns involved in the thermal reactions and rate-structure sensitivities of the alkyl species in the presence of the coadsorbed halogen atom. Multiple reaction pathways including metal etching processes which bear direct implications to the synthesis of organometallics and metal etching, are identified. It is becoming apparent that chemistry at surfaces, whether it be heterogeneous catalysis, semiconductor etching, or chemical vapor deposition, is controlled by much more than the nature and structure of the surface. Also, nonthermal activation of autocatalytic reactions is often required for the nucleation and growth of thin films in devices so that the stability of the device structure is maintained. Dynamical pathways followed in these high pressure and energy processes have to be well understood. The second part of these studies describe an investigation of collision-induced reaction of alkyl intermediates using supersonic inert gas atomic beams. Selective activation of a thermodynamically favored unimolecular decomposition reaction is initiated by hyperthermal collisions. Quantitative estimations of the reaction cross sections are made using straightforward hard sphere energy transfer dynamics. This successful demonstration of collision-induced activation of large, multiatomic moieties has paved the way for proposed studies (now underway in our group) on actual CVD precursors with known barriers to nucleation and growth. In the second section, the reaction mechanisms and kinetics of competitive dissociation, disproportionation, and thin film growth processes involved in the chemical vapor deposition of metal-silicide thin films are investigated. Metal-silicides are widely used as interconnect and gate materials in devices and also as corrosion resistant materials. Reactivity of silane and disilane with copper is studied in detail using temperature programmed reaction, Auger electron, Fourier transform infrared reflection absorption spectroscopies and low energy electron diffraction. For both the precursors, the structural chemistry and product distributions of adsorbed intermediates found at low temperatures are quite rich but significantly differ at the mechanistic level. It is shown quantitatively that disilane is almost 2-3 orders of magnitude more reactive than silane due to its facile Si-Si bond dissociation. However, in both cases, kinetics of silicon deposition and silicide formation are limited by the site-blocking effect of surface bound hydrogen generated by the decomposition of the silyl fragments. An ordered silicide overlayer is readily formed at higher coverages effected above dihydrogen desorption temperatures. This bimolecular process has to compete with an associative reaction which leads to the formation of silane. The results obtained from the different spectroscopic data show that the growth process involves an intriguing set of coupled reactions in which deposition, island growth, and Si etching effectively compete in a complex manner. Understanding of these parameters and the reaction mechanisms involved, enables the application of this process for the vapor phase growth of silicide thin films.

Scientific and Technical Aerospace Reports

Scientific and Technical Aerospace Reports PDF Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 704

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American Doctoral Dissertations

American Doctoral Dissertations PDF Author:
Publisher:
ISBN:
Category : Dissertation abstracts
Languages : en
Pages : 848

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Chemical Vapor Deposition and Characterization of Titanium Dioxide Thin Films

Chemical Vapor Deposition and Characterization of Titanium Dioxide Thin Films PDF Author: David Christopher Gilmer
Publisher:
ISBN:
Category :
Languages : en
Pages : 314

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