bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation Of Copper And Copper-Barium-Yttrium Sols From Metal 2-(2-Ethoxyethoxy)Ethoxides and Conversion Of Copper-Barium-Yttrium Alkoxide Precursors to Ba2YCu3O7−δ.
Authors: Scozzafava Mary Rose , Rhine Wendell E. , Cima Michael J. 
Published: March 2011

ABSTRACTThe hydrolysis of copper 2–(2-ethoxyethoxy)ethoxide solutions and barium-yttrium copper 2–(2-ethoxyethoxy)ethoxide solutions were investigated. Copper sols with particle sizesof 3–10 nm have been prepared from THF solutions. Sols from barium-yttrium-copper alkoxides were also prepared in THF with particle sizes of 4–10 nm as determined by transmission electron microscopy (TEM) and 50–80 nm as determined by photon correlation. Compositional analysis showed that the sols had a similar composition to the parent solution. Choice of atmosphere and solvent system played an important role in the progress of the hydrolysis reaction. Powders obtained from barium-yttrium-copper solutions can be converted to Ba2YCu3O7−δ.
Chemical Synthesis of Aluminum Nitride Powders
Authors: Coffman Phillip R. , Petuskey William T. , Dey Sandwip K. 
Published: March 2011

ABSTRACTAn organoaluminum precursor was synthesized by a low temperature reaction and characterized by NMR, FTIR and mass spectrometry. This compound was pyrolyzed under several experimental conditions to obtain aluminum nitride powders. The pyrolyzed products were subsequently characterized by XRD and SEM. The mechanisms of precursor development and subsequent pyrolysis are discussed.
Incorporation of Polyaniline Into a Silica Gel Via the Sol-Gel Technique
Authors: Nishida F. , Dunn B. , Knobbe E.T. , Fuqua P.D. , Kaner R.B. , Mattes B.R. 
Published: March 2011

ABSTRACTThe sol-gel process has been used to incorporate a conjugated polymer, polyaniline, in silica gel. The emeraldine base form of the polymer is partially solubility in aprotic polar solvents which are compatible with the sol. The effect of sol environment on the emeraldine base form of polyaniline was investigated. The soluble emeraldine base form is maintained at pH ≥ 2.4 enabling good optical quality gels to be synthesized. The type of alkoxysilane and the water ratio used in preparing the sol influence the solubility of the emeraldine base.
Vanadium Pentoxide Gels: Structural Development and Rheological Properties
Authors: Bailey J.K. , Nagase T. , Pozarnsky G.A. , Mecartney M.L. 
Published: March 2011

ABSTRACTCryogenic transmission electron Microscopy (cryo-TEM) and rheological characterization were conducted in order to understand structural development of vanadium pentoxide gels during processing. Sols were prepared by ion exchange from sodium metavanadate solutions. Cryo-TEM revealed that fine threads about 1.5nm wide initially form and grow into ribbons approximately 25nm wide and at least 1000nm long. The threads appear to self assemble into the ribbons. During this structural development, the dynamic viscosity increased. Upon steady shearing of the sols, the system exhibited thixotropy, i.e. the viscosity decreased with time under constant shear stress and subsequently rheopexy, the viscosity increased with time. Comparison of the structure before and after shearing indicated that during the rheological experiments aggregation of small particles or fragments was occurring.
High Resolution Tem of Organic Aerogels and Inorganic Aerogels
Authors: Ruben George C. , Pekala Richard W. 
Published: March 2011

ABSTRACTA base catalyzed silica aerogel and three base catalyzed resorcinol-formaldehyde (RF) aerogels were imaged with a new vertical platinum-carbon (Pt-C) replication technique. In deep gels single molecular chains can be visualized with transmission electron microscopy (TEM) with 9–10 Å thick Pt-C replicas backed with 110–130 Å of carbon [2]. The three RF aerogels produced with [Resorcinol]/[Catalyst] ratios (R/C) of 50, 200, and 300 had densities of 0.103, 0.063, and 0.065 gm/cc and had surface areas of 905, 580, and 390 m2/gm, respectively. The gel connectors and junctions in RF 300 and RF 200 were composed of 210±30 Å and 140±10 Å beads which were joined by polymeric chains covering an area less than half the bead's diameter and within a bead diameter's distance. The gel connectors and junctions in RF 50 were frequently composed of beads of about 120±10 Å joined over an area larger than half the bead's diameter. Similar to the silica aerogel (0.065 gm/cc, 113±10 Å beads), the beads were frequently connected over several bead diameter's distance from each other.
A New Synthetic Route to Organic Aerogels
Authors: Pekala R.W. , Alviso C.T. 
Published: March 2011

ABSTRACTThe aqueous, sol-gel polymerization of melamine with formaldehyde, followed by supercritical extraction, leads to the formation of a new type of organic aerogel. Synthetic conditions (e.g. reaction time, pH) affect the density, transparency, and microstructure of the resultant aerogels. Unlike previous organic aerogels based upon resorcinol-formaldehyde, the melamine-formaldehyde aerogels are both colorless and transparent. Low densities (0.1–0.8 g/cc), high surface areas (∼1000 m2/g), and optical clarity are only a few of the promising characteristics of this new material.
Pre-Resonance Raman Characterization of Metal-Organic Films from Titanium Alkoxide Carboxylate Complexes
Authors: Gagliardi Charles D. , Dunuwila Dilum , Berglund Kris A. 
Published: March 2011

ABSTRACTMetal-organic films were produced at ambient temperatures and pressures by the controlled hydrolysis of carboxylic acid and titanium isopropoxide mixtures. Pre-resonance Raman spectroscopy was used to study the effect of the organic acid chain length upon the nature of the resulting film. Propionic, butyric, valeric, hexanoic, and octanoic acids were studied, resulting in a proposed correlation between film quality and certain spectroscopic features of the alkoxide carboxylates. The choice of the carboxylic acid and the presence of an appropriate amount of water were shown to be critical in the development of a good film.
XPS Characterization of Mixed Carbides Obtained from Polymer Precursors
Authors: Granozzi Gaetano , Glisenti Antonella , Soraru Gian D. 
Published: March 2011

ABSTRACTPolymer precursors for Si-C, Si-Ti-C-O and Si-Al-C-O systems have been obtained from polycarbosilane and the corresponding metal alkoxides. X-ray Photoelectron Spectroscopy (XPS) has been used to follow the structural evolution of these preceramic compounds during the pyrolysis process.
Chemically Derived Yttria-Stabilized Zirconia for Plasma-Spraying
Authors: Sherif Fawzy G. , Herman H. 
Published: March 2011

ABSTRACTYttria-stabilized zirconia powders were prepared by three chemical routes utilizing emulsion hydrolysis techniques. Metal alkoxides, acetates and mixtures of alkoxides and acetates were used as starting materials. Under controlled hydrolysis conditions, particles with different morphology and size were obtained. Spherical or granular particles in the range of 20–60u in diameter were formed. The grain size varied from 0.1–0.2u. The powders were applied successfully as plasma spray coatings. The chemical uniformity was demonstrated by the presence of 100% non-transformable tetragonal zirconia in the powder and in the coating.
Transpiration Cooled Porous Type Vi Silica Rocket Windows
Authors: Fosmoe II Albert G , Hench Larry L. 
Published: March 2011

ABSTRACTA novel use of sol-gel derived porous Type VI silica for high performance rocket guidance system windows is evaluated. The samples produced for this study were optically transparent hydrofluoric and/or nitric acid catalyzed tetramethylorthosilicate (TMOS) xerogel monoliths with average pore radii of 1.2, 5.0, and 8.Onm. Maximum He transpiration velocities of up to 3 cm/sec, 3 times the velocity needed for transpiration cooling, are measured for a 5.0 nm sample at 3.2 MPa. Transpiration velocities of 0.6 cm/sec result in cooling effects as large as 44°C from 160°C.
Morphology Control In Precursor Ceramic Powder Production By The Electrical Dispersion Reactor
Authors: Harris Michael T. , Scott Timothy C. , Basaran Osman A. , Byers Charles H. 
Published: March 2011

ABSTRACTThe Electrical Dispersion Reactor (EDR) allows the continuous production of composite oxide ceramic precursor materials. Silica particles in the form of highly porous shells are produced by the hydrolysis of tetraethylorthosilicate as the continuous phase and water-ammonia as the disperse phase, reflecting the diffusion of the silicon moiety into the dispersed phase. Alternately, denser silica particles result when aqueous solutions of sodium metasilicate are dispersed in a continuous phase containing acetic acid in 2-ethyl-1-hexanol. Additionally, spherical particles in the size range 0.1 to 2 microns are produced from the dispersion of aqueous solutions containing cupric chloride or a mixture of cupric chloride, yttrium nitrate, and barium nitrate (3:1:2 molar ratio) into a continuous organic phase containing ammonia.
Effect of Nitrous Oxide Gas on Cvd Diamond Film Deposition
Authors: Koinuma H. , Yoshimoto M. , Takagi Y. , Sawaoka A. B. , HaHashimoto T. , Nagai T. , Shiraishi T. 
Published: March 2011

ABSTRACTThe addition of nitrous oxide (N2O) gas in the hot-filament chemical vapor deposition of carbon film from mixtures of methane and hydrogen was found to increase remarkably the content of diamond structure in the film. Increased particle size and crystal orientation parallel to the (111) direction were also obtained by the N2O addition. Mass spectrometry revealed that the vapor phase reaction was scarcely affected by the N2O addition.
Synthesis of Superconducting Perovskite by Coprecipitation of Hydroxides
Authors: Valente-Campion I. , Barboux P. , Mazerolles L. , Michel D. , Morineau R. , Livage J. 
Published: March 2011

ABSTRACTThe synthesis of the superconducting perovskite YBa2Cu3O7 using hydroxides as starting precursors has been investigated. Hydroxides are homogeneously coprecipitated from mixed alcohol-water solutions without loss of barium. Upon heat-treatment the perovskite phase rapidly forms around 750°C. However, it remains tetragonal even after long time annealing in oxygen ambient. This is related to an unusual microtwinning in the (ac) plane.
Preparation of Bi-Pb-Sr-Ca-Cu-O Superconductor By Thermal Decomposition of an Edta Colloid
Authors: Koo H.S. , Chiang C.K. , Huang Y.T. , Tu G.C. 
Published: March 2011

ABSTRACTHigh-Tc superconducting Bi-Pb-Sr-Ca-Cu oxide with zero resistance temperature at above lOOK has been synthesized via the use of ethylenediamine-tetra-acetate(EDTA) colloid and corresponding metal nitrates. Remarkable sinterability of the precursor requires shorter time to achieve superconducting phases than conventional solid-state reactions. Superconducting properties were measured electrically and magnetically. The thermal decomposition, X-ray diffraction and microstructural characteristics of the precursor and the sintered samples were also discussed.
Solution-Derived Yba2Cu,Sub3O7−Δ. Thin Films And Barrier Layers
Authors: Whitwell G. E. , Wandass J. H. , Cambria F. M. , Antezzo M. F. 
Published: March 2011

ABSTRACTHydrolyzed metal alkoxide solutions were spin-coated on Si substrates with subsequent thermal processing. Barrier layers of alkaline earth oxides, perovskites, Y2O3, ZrO2 and others were produced. Characterization was performed via SEM, XRD, ESCA, Auger depth profiling and resistivity measurements. Barrier layer films were fairly smooth with some cracking and pitting present. Si migration was severe for alkaline earth thin films on Si wafers. Some perovskite films on Si showed formation of Ba-Si-O phases at the Si interface. Thin films of 1–2–3 on barrier layers of SrTiO3 or ZrO2 on Si showed Ba pileup at the Si interface and were not superconducting. 1–2–3 layers deposited on single crystal ZrO2 were superconducting and showed onset temperatures of 90 K with zero resistance reached at about 55 K.
Evaluation Of YBa2Cu3O7-δ Sol-Gel Derived Films On Sapphire Substrates Produced From Different Cu(Ii) Alkoxide Groups.
Authors: Kenzer D.S. , Teepe M.R. , Moore G.A. , Kordas G. 
Published: March 2011

ABSTRACTYttrium methoxyethoxide, barium methoxyethoxide and various copper(II) alkoxide groups were used as precursors for the formation of YBa2Cu3O7-δ stable sols in a 2- methoxyethanol / methyl ethyl ketone / toluene / diisopropyl ketone solvent system. Sol fractal dimensions were varied with the sol concentration and with the addition of pyridine. Strong correlation was found between the wettability and the fractal dimensions of the various precursors as determined by contact angle measurements. YBa2Cu3O7-δ thin films were deposited on sapphire substrates using a dip-coating technique. The films were fired at 850°C under flowing oxygen or an ozone/oxygen mixture. Although the ozonetreatments helped in the formation of single YBa2Cu3O7-δ phase, they contributed to extensive cracking in the films. The different copper(II) alkoxide precursors had little effect on final film microstructure.
Aspects Of Chemistry and Chemical Processing Of Organically Modified Ceramics
Authors: Schmidt Helmut K. 
Published: March 2011

ABSTRACTFor the synthesis of composites on a nano or molecular level, chemical or physical methods have to be used since mechanical procedures cannot be employed for these systems. If organics have to be included, low temperature processing has to be used for the synthesis of the inorganic component in order not to damage the organic component. Sol-gel techniques are an appropriate means to synthesize oxidic networks by soft chemistry, and various systems of organically modified ceramics (ORMOCERs) have been developed so far. It has been shown that the synthesis parameter can be used to tailor the material properties in a wide range. A review over the chemistry and chemical properties of ORMOCERs and several examples of material developments will be given.
Hydrolysis of Aluminum -Are All Gels Created Equal?
Authors: Wood T. E. , Siedle A. R. , Hill J. R. , Skarjune R. P. , Goodbrake C. J. 
Published: March 2011

ABSTRACTThe nuclearity and structure of aluminum cations generated by the hydrolysis of aluminum salt solutions depends markedly on the method of preparation. This speciation affects not only the thermochemistry of processes leading to ceramics, but the microstructures of the ceramics themselves. A brief review of aluminum ion hydrolysis is presented along with a study of the thermal evolution of gels derived from aluminum salt solutions via several different hydrolysis methods. The observation of 5 - coordinate aluminum in a bulk transition alumina by MAS-NMR is reported. A new, high defect precursor of η-alumina dubbed “high-5 alumina” is described and the far reaching implications of this discovery are discussed.
Modelling Diffusion in and From Polysilicon Layers
Authors: Hill C. , Jones S.K. 
Published: March 2011

AbstractThe physical processes involved in dopant redistribution during heat treatments of polysilicon layers are described, and one and two—dimensional models based on these are presented. The quantitative effects of the physical parameters determining arsenic andboron distributions in bipolar VLSI emitter—base structures are demonstrated, andclose correspondence shown with available experimental data. Areas needing new models are outlined, and an approach to the modelling of epitaxial alignment is proposed.
In-Situ Doped Polycrystalline Silicon Deposited by Rapid Thermal Chemical Vapor Deposition Using Tertiarybutylphosphine
Authors: Liao Jimmy C. , Kim Ki-Bum , Maillot Philippe 
Published: March 2011

AbstractThe effects of using tertiarybutylphosphine (TBP) as a source of phosphorus dopants during polycrystalline silicon (polysilicon) deposition in a rapid thermal processor (RTP) was investigated using TEM, SIMS, spectrophotometry, and 4-point probe analysis. It was found that the introduction ot TBP significantly inhibited the deposition of polysilicon on silicon dioxide, but only slightly reduced the growth rate of polysilicon on polysilicon. The introduction of TBP during the last 20% of the deposition time formed a thin phosphorus-rich layer on the top surface. Adsorption of the phosphorus was found to be gas-transport-limited. Incorporation of the dopant into the rest of the polysilicon layer was accomplished with an in-situ anneal (RTA) in nitrogen, resulting in a resistivity as low as 720 μΩ-cm.The grain size of the polysilicon was found to increase with deposition temperature, however was not affected by the introduction of the dopant, or any subsequent anneal. It ispostulated that unincorporated phosphorus, and oxygen and carbon in the grain boundariesprevent the combination and growth of silicon crystals.
Supersaturated P-Type Polycrystaline Films Produced by Rapid Thermal Annealing of High Dose Boron Ion Implants for Interconnects and Shallow Junction Diffusion Sources
Authors: Raicu B. , Current M.I. , Keenan W.A. , Mordo D. , Brennan R. , Holzworth R. 
Published: March 2011

AbstractHighly conductive p+-polysilicon films were fabricated over Si(100) and SiO2 surfaces using high-dose ion implantation and rapid thermal annealing. Resistivities close to that of single crystal silicon were achieved. These films were characterized by a variety of electrical and optical techniques as well as SIMS and cross-section TEM.
Electrical and Optical Properties of Polysilicon Sheets for Photovoltaic Devices Grown From Powder
Authors: Urli Natko B. 
Published: March 2011

AbstractIn a search for low-cost and high efficiency solar cell manufacturing, several techniques of growing thin silicon sheets from powder have been adopted, such as: plasma spraying on various substrates, zone-melting using incoherent focussed light as heat source, and low-angle horizontal pulling of thin ribbon over the melted tin-lead support. Undoped, and n- and p-type silicon powders of various grain sizes have been used as starting materials, with pure graphite, quartz, or low-cost ceramics serving as temporary or permanent substrates. N+/p +/n junctions, and back surface fields were formed by implanting PF 5 and BF 3+ ions in a glow discharge ion implanter at ultralow energies (less than 1 keg) and high total ion doses. Ion induced damage was annealed by RTP in the incoherent light furnace at temperatures as low as 700°C.Structural and optoelectronic properties of as-grown and processed thin polysilicon sheets were determined by Raman spectroscopy, spectral response, and electrical transport measurements. A sharp peak at 520 cm−1 in the Raman spectra, associated with TO ((Г) phonons, indicated a good crystallinity of polysilicon sheets. High values of short-circuit currents, and an almost flat spectral response down to 400 nm, without intentionally applying a surface passivating oxide, illustrate the advantage of the applied novel technologies.
Effects of Arsenic Segregation and Electron Trapping on the Capacitance-Voltage Behavior of Polysilicon and Polycide Gates
Authors: Lin J. , Batra S. , Park K. , Lee J. , Banerjee S. , Sun S. , Yeargain J. , Lux G. 
Published: March 2011

AbstractThis paper discusses the effects of dopant segregation and electron trapping on the capacitance-voltage characteristics of arsenic-implanted polysilicon and amorphous Si gate MOS structures fabricated with and without a TiSi2 layer. The effects of gate bias, annealing temperature, silicide formation and polysilicon grain microstructure on the C-V characteristics have also been studied. The results show that insufficient arsenic redistribution at 800°C, coupled with carrier trapping at polysilicon grain boundaries and dopant segregation in TiSi2 causes depletion effects in the polysilicon gate and in turn, an anomalous capacitance-voltage behavior. The depletion tends to increase the “effective” gate oxide thickness and thereby degrade MOS device performance. Higher temperature anneals (≥ 900°C) are sufficient to achieve degenerate doping in the polysilicon gates and avoid the depletion effects.
Application of Polysilicon in Advanced IC - Technologies
Authors: Kabza Herbert , Meister Thomas F. , Schaber Hans 
Published: March 2011

AbstractThe progress in IC technology is unthinkable without the extensive use of polysilicon for a wide variety of purposes. These range from simple passive components like resistors and contacts through more complex structures such as recrystallized layers for SOI and 3D techniques, poly-Si filled isolation trenches and electrodes of DRAM capacitors to active device applications, i.e. MOS gates and poly-Si emitters in bipolar transistors. As silicide or in combination with such polysilicon allows practical local interconnects.
Polycrystalline Silicon in ULSI Technologies: Challenges for Deep-Submicron Structures
Authors: Wong Catherine Y. , Ning Tak H. 
Published: March 2011

AbstractPolysilicon is a key material widely used in MOSFET, bipolar, and BICMOS devices. As these technologies evolve into the deep submicron regime, several issues emerge in the applications of polysilicon that must be addressed. In sub-0.5µm MOSFET, fabrication and reliability of n + poly for NMOS and p + poly for PMOS should be studied. In bipolar technology, scaling limits of polysilicon emitter must be investigated. Understanding polysilicon, both in terms of its basic material and process characteristics and its characteristics in specific integrated process and/or integrated device structures, is definitely required in order to realize the full potential of ULSI technologies.
Polysiliodn Annealing and its Inflience on Floating Gate Eeprom Degation
Authors: Seim Rakesh B. , Andeion L. B. 
Published: March 2011

AbstractExperimental results on the influence of prooessing on degradation of thin silicon dioxide films are reported. The high temperature polysilicon oxidation degrades the integrity and robustness of thermally grown dry oxide as shown by constant current charge to breakdown measuremeits.Furthermore the influence of high temperature processing on the charge trapping properties of the tunnel oxide (silicon dioxide) are ascertained. The details of electron trapping its capture cross section, areal concentration and trapping efficiency as studied by high field dark current-voltage method is presented. Generally, the dominant −15 electron trap with a large capture cross section of 10 cm2 is observed and is believed to be due to phosphorus near polysilicon/thin oxide interface. In addition the QBD reduction is correlated to outdiffusion of water from the thin oxide as seen by reduction in the hysteretic instability of I-V curves.
Impact of Various Polysilicon Deposition Process on Thin Gate-Oxide Properties in Submicron CMOS Technology
Authors: Roy P. K. , Kook T. , Kannan V. C. , Felton G. J. , Powell R. A. , Velaga A. N. 
Published: March 2011

AbstractThe dielectric quality (defect density, Do and breakdown strength, Fbd) of 150Å SiO2 gate oxide (GOX) films grown by conventional or stacked oxidation scheme are discussed from the leakage measurements of polysilicon capacitors on test structure simulating our submicron CMOS process. Various polysilicon (poly) deposition processes from silane pyrolysis (570°C -620°C) were used by the low pressure chemical vapor deposition (LPCVD) technique. Both in situ and ex situ poly doping by phosphorus (P) were used to ascertain their impact on the GOX properties. The substructural characteristics of the poly/SiO2 and SiO2/Si interfaces generated by various combinations of GOX and poly deposition processes were done by the high resolution TEM lattice fringe technique under phase contrast mode.