bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phase Behavior of Triblock Copolymers upon Incorporation of Non-Parent, Midblock-Associating Additives
Authors: Laurer J. H. , Mulling J. F. , Bukovnik R. , Spontak R. J. 
Published: April 2011

ABSTRACTAddition of a block-selective homopolymer to a microphase-ordered block copolymer is known to result in preferential swelling of the chemically compatible microdomain. In this work, we examine the miscibility between a triblock copolymer and a relatively low-molecular-weight, chemically dissimilar, midblock-associating homopolymer and demonstrate that the homopolymer molecules residing in the swollen midblock matrix self-assemble to avoid repulsive interactions with neighboring microdomains. We extend this investigation to include systems composed of a very low-molecular-weight, midblock-associating additive (an oil). At high oil concentrations, the glassy copolymer endblocks micellize, resulting in the formation of a thermoplastic elastomer gel.
Interfacial Reaction and Electrochemical Activity of Thiokol Rubber/Conjugated Polymer Composites
Authors: Ke-Cheng Gong , Wen-Shi Ma 
Published: April 2011

ABSTRACTThe highly electroactive thiokol rubber (TR)/ conjugated polymer (eg. polyaniline (PAn) or polypyrrole (PPy)) composite films were prepared by electropolymenzation deposition via one-step process in the electrolytic solutions containing aniline or pyrrole and TR oligomer. The electrocatalysis of PAn or PPy for the electrodepolymerization (reduction)- electropolymenzation (oxidation) reaction of TR in the interface between PAn or PPy and TR is determined by cyclic voltammograms. The differeme between the oxidation potential and the reduction potential is 0.05V and 0.36V or less for TR/PAn and TR/PPy composite films, respectively The chemical bands between the nitrogen atoms of PAn or PPy and the mercaptan groups of TR (oligomer) are formed in the electropolymenzation process that is indicated by XPS. The conductivities of TR/PAn and TR/PPy composite films and the stability of the cells consisting of those films are remarkably improved after electrochemical reduction with addition of a suitable conducting carbon black.
An Examination of Contemporary Iznik-Style Turkish Ceramics
Authors: Artal-Isbrand P. , Newman R. 
Published: April 2011

ABSTRACTContemporary hand-made Iznik-style ceramics continue to be popular in Turkey. Made in some 50 workshops in Kiitahya and one workshop in Iznik, these wares generally show the same stratigraphy as the traditional Iznik wares produced during the Ottomon Empire from the 15th-17th centuries. While the materials utilized in the modern wares show some similarities to the traditional wares, the modern ceramicists have adopted many modern materials. For this paper, crossections of ceramics from four modern workshops were analyzed in an electron beam microprobe and the results compared with published information on traditional Iznik ceramics.
Mineralization in Archaeological Skin: An Interdisciplinary Approach to Conservation Processes and Contextual Relations
Authors: Cruz-Flores S. , Gama-Castro J.E. 
Published: April 2011

ABSTRACTDetermining the composition and microdeposition of minerals, and their relation with the skin, are basic in order to understand the mechanisms, dynamics and environmental conditions that take place in the burial context. The present research has been developed with the objective of obtaining information that will contribute to increasing our knowledge of the modification processes in the preserved skin, verified inside an archaeological context.
Machine Vision as a Materials Conservation Technology
Authors: Samajdar S. 
Published: April 2011

ABSTRACTConservation of archaeological monuments and artifacts is in need of precise and efficient techniques for materials condition evaluation in order to ensure accurate diagnosis followed by effective curative intervention. Machine Vision, already extensively used in the manufacturing industry, is introduced as a preservation technology to fulfill that need. Material degradation manifests itself as localized variations in the optical response (e.g., color & intensity) from the affected surface. Once captured through an appropriate recording device, the image of the surface is documented, enhanced, analyzed and displayed by use of Digital Image Processing (DIP) techniques. The resulting map of materials condition for the surface is demonstrably comprehensive, quantitative & accurate, and the process is fast and economical. Field work was done at the site of Mayan ruins in Tulum, Mexico, on the shore of the Caribbean sea. This paper focuses on a piece of structural rock having a large number of surface pores as the primary form of degradation. Employing DIP procedures, the material condition of the surface is quantitatively represented and characterized in terms of size as well as spatial distribution of the damage features. On a theoretical note, it is postulated that the sand from the beach, airborne by the sea breeze, had been the principal erosion agent. And a phenomenological model of the weathering mechanism has been developed centering on the fluid mechanical concept of terminal velocity. Close agreement between the field work data and the theoretical construct demonstrates the additional merit of the adapted technology as enabling a verifiable, and hence more meaningful, diagnosis of the weathering mechanism.
A Novel Stem-Based Mass Spectroscopic Technique: Applications to Catalytic Materials
Authors: Yang J. C. , Singhal A. , Bradley S. , Gibson J. M. 
Published: April 2011

ABSTRACTVery high angle (∼ 100mrad) annular dark-field (HAADF) images in a dedicated scanning transmission electron microscope (STEM) can be used to quantitatively measure the mass of a cluster on a support material. With knowledge of the annular dark field (ADF) detector efficiency, the absolute intensity of very HAADF images can be converted to elastic scattering cross-sections. By comparing the theoretical and experimental elastic scattering cross-sections, the number of atoms can be determined. Statistical measurement of absolute cross-sections from Re-6 clusters show good agreement with theoretical cross-sections. The experimental error corresponded to ±2 Re atoms. Our experiments demonstrate the exceptional stability of the Re-6 organometallic compound relative to Re-8 clusters. This technique is presently being applied to Pt clusters.
A Combined-Techniques Approach to Elucidating Crystalline Interface Atomic Structure
Authors: Dickey E. C. , Dra Vid V. P. , Pennycook S. J. , Nellist P. D. , Wallis D. J. 
Published: April 2011

ABSTRACTA case study is presented in which HREM, Z-Contrast Imaging and EELS are used as complementary techniques for elucidating interface structure. The NiO-ZrO2(cubic) interface is investigated along two orthogonal directions by these electron imaging and spectroscopy techniques to reveal the three-dimensional interface structure. Based on findings from this study, a protocol is suggested for using all three experimental techniques to gain a thorough understanding of interface structures.
Chemical Imaging of InGaAs/InAiAs Quantum Wells
Authors: Mountjoy G. , Crozier P. A. , Fejes P. L. , Tsui R. K. , Kramer G. D. 
Published: April 2011

ABSTRACTWe have applied high resolution chemical imaging in a transmission electron microscope to study compositional variations across InGaAs/InAIAs double quantum well structures. The structures of interest are grown on an InP substrate and consist of two 40 Å layers of InGaAs separated by 20 Å of InAlAs. For this (InGa)x(InAl)1-xAs system, we have been able to obtain compositional information with an accuracy of about 20 % and a maximum spatial resolution of 1/2 × 1/2 unit cell. The results clearly show irregularities on a monatomic scale.
Cross Sectional AFM of Oxidized Porous Silicon
Authors: Ye Weijun , Poler Jordan , Drozd B. , Hasan M. A. 
Published: April 2011

ABSTRACTMorphological studies of bulk porous-silicon (PS) are presented. Using the atomic force microscope, cleaved cross-sections of electrochemically processed porous-silicon were investigated. The porous-silicon/silicon interface was examined. Using a room temperature UV O3 generator, the porous silicon-samples were oxidized. Oxidation in air was also observed. The morphology of the oxidized porous-silicon is process dependent. AFM contrast was enhanced by selective wet chemical etching. Unusually fast oxide etching in BOE was observed. A possible oxide/PS model is proposed.
Kinetic Model of Thermal Donor Evolution
Authors: Kelton K. F. , Falster R. 
Published: April 2011

ABSTRACTKinetic aspects of thermal donor (TD) formation in Czochralski silicon are shown to be consistent with the evolution of small oxygen clusters, as described within the classical theory of nucleation. Predictions for TD generation and interstitial oxygen loss are presented. Favorable agreement with experimental data requires that the rate constants describing cluster evolution be increased over those expected for a oliffusion-limited flux based on a normal diffusion coefficient for oxygen in silicon. This may signal an anomalously high diffusion rate for temperatures less than 500°C, as has been suggested by others. However, it may instead signal an enhanced concentration of free oxygen near clusters smaller than the critical size for nucleation. This is expected when the interfacial attachment rates become comparable with the rates at which oxygen atoms arrive in the vicinity of the sub-critical clusters. The link between thermal donor generation and oxygen precipitation processes demonstrated here provides a consistent framework for better understanding and controlling oxygen precipitation in silicon. Further, the kinetic TD generation and oxygen loss data provide a new window into the dynamical processes for small clusters, which underlie all nucleation phenomena.
Low Energy Implantation and Transient Enhanced Diffusion: Physical Mechanisms and Technology Implications
Authors: Cowern N. E. B. , Collart E. J. H. , Politiek J. , Bancken P. H. L. , Van Berkum J. G. M. , Kyllesbech Larsen K. , Stolk P.A , Huizing H. G. A. , Pichler P. , Burenkov A. , Gravesteijn D. J. 
Published: April 2011

ABSTRACTLow energy implantation is currently the most promising option for shallow junction formation in the next generations of silicon CMOS technology. Of the dopants that have to be implanted, boron is the most problematic because of its low stopping power (large penetration depth) and its tendency to undergo transient enhanced diffusion and clustering during thermal activation. This paper reports recent advances in our understanding of low energy B implants in crystalline silicon. In general, satisfactory source-drain junction depths and sheet resistances are achievable down to 0.18 micron CMOS technology without the need for implantation of molecular species such as BF2. With the help of defect engineering it may be possible to reach smaller device dimensions. However, there are some major surprises in the physical mechanisms involved in implant profile formation, transient enhanced diffusion and electrical activation of these implants, which may influence further progress with this technology. Some initial attempts to understand and model these effects will be described.
Experimental Investigation of Transient Enhanced Diffusion (TED) of Phosphorus Implants in Silicon in the MeV Range
Authors: Adam Lahir S. , Law Mark E. 
Published: April 2011

ABSTRACTTransient Enhanced Diffusion (TED) is one of the biggest modeling challenges present in predicting scaled technologies. Prior work has concentrated on TED resulting from sub 200 KeV implants. However, the results applicable to the low energy regime cannot be extrapolated per se into the high energy regime. Furnace anneals have been performed and through simulations it has been observed that there is a differential diffusivity enhancement between the part of the profile before the profile peak and that beyond the profile peak. Longer saturation times compared to the low energy implants have also been observed.
Formation of Counter Doped Shallow Junctions by Boron and Antimony Implantation and Codiffusion in Silicon
Authors: Solmi S. , Canteri R. 
Published: April 2011

ABSTRACTVery shallow p+/n junctions (lower than 60 nm) have been fabricated by implanting Sb and subsequently BF2, at a higher dose, in a n-type Si substrate. The preamorphisation with Sb avoids the B channeling and increases the n-type doping in the junction region, thus confining the depth of the p layer. Furthermore, both the transient enhanced diffusion, being the B implanted in a preamorphized layer, and the standard diffusion, due to the pairing between donors and acceptors, are strongly reduced. This procedure allows us to obtain very shallow junctions even after annealings with relatively high thermal budget, like 800 C/8h, or 900 C/lh, or 950 C/15min or 1000 C/60s. Dopant diffusion is strongly affected by the direct donor-acceptor interaction. Good agreement between experimental and simulation results can only be obtained using a simulation code which takes into account the formation of neutral, near immobile, Sb-B pairs.
The Influence of Amorphizing Implants on Boron Diffusion in Silicon
Authors: Chao H. S. , Griffin P. B. , Plummer J. D. 
Published: April 2011

ABSTRACTThe transient enhanced diffusion behavior of B after ion implantation above the amorphization threshold is investigated. The experimental structure uses a layer of epitaxially grown Si, uniformly doped with B to act as a diffusion monitor. Wafers using this structure are implanted with amorphizing doses of Si, As, or P and annealed for various times at various temperatures. The experimental results show that upon annealing after Si implantation, there is a large amount of B pile-up that occurs at the amorphous/crystalline (A/C) interface while B is depleted from the region just beyond the A/C interface. This pile-up/depletion phenomenon can be attributed to the dislocation loops that form at the A/C interface. These loops act as sinks for interstitial point defects. There is also B pile-up/depletion behavior for As and P implants as well. However, this behavior may be explained by an electric field enhancement effect. While dislocation loops are known to form at the A/C interface for all of the investigated implant conditions, it appears that while they are necessary to simulate for Si amorphizing implants, they may not be necessary to simulate for As and P amorphizing implants.
Low Level Cu Contamination of Silicon During Wet Cleaning Studied by Transient Ion Drift
Authors: Heiser T. , Mchugo S. , Hieslmair H. , Weber E. R. 
Published: April 2011

ABSTRACTInterstitial copper (CUi) drift induced transient capacitance signals of a Schottky barrier are analysed after copper indiffusion at various temperatures and thermal quenching. Against the general expectation we show that most Cu impurities remain interstitially dissolved. Consequently, such transient ion drift analyses can be used to detect copper in silicon with a detection limit of the order of 1011cm−3. We applied the method to study Cu contamination of silicon samples after chemical cleaning and high temperature annealing. After a short dip into a copper contaminated aqueous solution and subsequent annealing at 1000C for 10 minutes, a strong correlation is found between the bulk copper concentration and the copper density in the solution. A density as low as 50 atomic parts per billion is found to be sufficient to induce a bulk copper concentration of about 5.1013cm−3.
Study of Point Defect Concentrations During the Fluorinated Oxidation of Silicon
Authors: Jaccodine R. J. , Kim U. S. 
Published: April 2011

ABSTRACTSome of our most important and quantitative insights on intrinsic point defects have been established as a result of the study of the influence of oxidation on their “excess” concentrations. From study of the growth and shrinkage of oxidation induced stacking faults (OSF) and from oxidation enhanced or retarded diffusion (OED-ORD) the fractional contribution of self-interstitials and vacancies can be assessed. The dominant influence on relatively thin dry or wet oxides is that of the injection of self-interstitials away from the oxidizing interface into the bulk crystal. These self-interstitials have been variously attributed to the incompleteness of oxidation or interracial stress and relaxation at the Si-SiO2 interface. We have studied the role of fluorine additives (ppm) to the dry oxidation process. This paper will discuss similar oxidation-related phenomena (OSF, OED, and ORD), confirming that under our experimental conditions with normally dry oxidation plus fluorine the active point defect injection consists mainly of “excess” vacancies. OSF anneal at lower temperatures than with nitridation processes and with a lower activation energy (1.7 eV). The study of P,B,As, Sb oxidation enhances-retarded diffusions validates the conclusion, with P,B yielding ORD instead of OED and Sb being enhanced rather than retarded as in normal oxidation. Oxidation-induced diffusion experiments not only explored the role of the specific impurity (P,B,As,Sb) but also utilized specimens with four adjacent active regions (bare Si, oxide covered Si, nitride covered Si, and the normal control oxide covered by nitride). The ratios of Ci/Ci* and Cv/Cv* for fluorine addition will be contrasted with those formed by dry oxidation.
Microstructure and Optoelectronic Properties of CdSe-Thin Films
Authors: Klement U. , Ernst F. 
Published: April 2011

ABSTRACTCdSe appears to be a promising material to replace amorphous hydrogenated silicon as the photosensitive part in the retina of the “Electronic Eye”, a camera based on thin film technique. We have investigated the influence of post-depositional annealing treatments with respect to the optimization of the photoconductive properties. TEM-, AFM- and XPS-measurements on CdSe thin films are reported. The formation of an oxide could not be detected by XPS-depth profiling of films annealed in air but chemisorption of oxygen is expected at the intergrain boundaries. Hence, high potential barriers for electron transport will be introduced. Under illumination, trapping of photo-generated holes will neutralize the charge at the intergrain boundaries leading to improved electric properties. However, the homogeneity of the photoconductive properties in CdSe is not yet satisfying. The formation of swellings and holes on the sample surface, found by AFM-measurements, can perhaps explain the inhomogeneity of the photoconductive properties. Using Si wafers as substrate material no improvement in texturing could be reached, since an amorphous CdSe-interlayer is formed.
Comparison of the Structure of Grain Boundaries in Silicon and Diamond by Molecular-Dynamics Simulations
Authors: Keblinski P. , Phillpot S. R. , Wolf D. , Gleiter H. 
Published: April 2011

ABSTRACTMolecular-dynamics simulations were used to synthesize nanocrystalline silicon with a grain size of up to 75 Å by crystallization of randomly misoriented crystalline seeds from the melt. The structures of the highly-constrained interfaces in the nanocrystal were found to be essentially indistinguishable from those of high-energy bicrystalline grain boundaries (GBs) and similar to the structure of amorphous silicon. Despite disorder, these GBs exhibit predominantly four-coordinated (sp3-like) atoms and therefore have very few dangling bonds. By contrast, the majority of the atoms in high-energy bicrystalline GBs in diamond are three-coordinated (sp2-like). Despite the large fraction of three-coordinated GB carbon atoms, they are rather poorly connected amongst themselves, thus likely preventing any type of graphite-like electrical conduction through the GBs.
In-Plane Crystallographic Texture of Bcc Metal thin films on Amorphous Substrates
Authors: Harper J.M.E. , Rodbell K.P. , Colgan E.G. , Hammond R.H. 
Published: April 2011

ABSTRACTWe show that dramatically different in-plane crystallographic textures can be produced in body centered cubic (bcc) metal thin films deposited under different conditions. The orientation distribution of polycrystalline bcc thin films on amorphous substrates often has a strong (110) fiber texture, and an in-plane texture may develop when deposition takes place with an off-normal incidence flux of energetic ions or atoms. Three orientations in Nb films have been observed in which the energetic particle flux coincides with crystal channeling directions. In-plane orientations in Mo films have also been obtained in magnetron sputtering systems. The selected orientations are reviewed, and examples are given in which the in-plane orientation of Mo deposited in two similar magnetron sputtering systems differs by a 90° rotation. The origins of in-plane texture in rectangular magnetron sputtering systems are discussed.
Analysis of Residual Stress in Polycrystalline Silver Thin Films by X-Ray Diffraction
Authors: Alford T. L. , Zeng Yuxiao , Zou Y. L. , Deng F. , Lau S. S. , Laursen T. , Manfred Ullrich B. 
Published: April 2011

ABSTRACTThe stress state of evaporated Ag films prepared on Ti underlayers before and after encapsulation process has been studied by x-ray diffraction using a “sin2ψ” technique. A low tensile stress of approximately 61 MPa was measured in the as-deposited Ag films. The stress was caused by nonequilibrium growth during film deposition and resulted in a lattice tension state in the film plane and a lattice compression state along the film normal. Thermal mismatch stress was produced by the encapsulation process at 600 °C, but most of this stress relaxed during the cooling stage, and a residual tensile stress of ∼ 320 MPa in the film plane was determined.
Study on Relaxor Ferroelectric Thin Films of Tungsten Bronze Pb1-xBaxNb2O6 by RF Magnetron Sputtering
Authors: Xiao X. , Xu N. , Li L. 
Published: April 2011

ABSTRACTFerroelectric thin films of tungsten bronze lead barium niobáte (PBN) were fabricated by radio frequency magnetron sputtering. Oriented growths of the thin films were observed along (001) in tetragonal phase and along (002) in orthorhombic phase. Excess amount of PbO (6 wt %) in the PBN targets were used to compensate Pb evaporation during sputtering deposition. Ferroelectric properties were investigated as a function of annealing temperatures. The thin film with high quality was annealed at 650 °C, while its remnant polarization (Pr) and coercive field (Ec) were equal to 47.9 μC/cm2 and 5.2 kV/cm, respectively.
Tensile Behavior of Free-Standing Gold Films
Authors: Emery R.D. , Lenshek D.X. , Behin B. , Gherasimova M. , Povirk G.L. 
Published: April 2011

ABSTRACTA method for tensile testing thin gold films is presented. Free-standing tensile specimens were prepared by evaporating 0.8 μm of gold onto a patterned oxidized silicon wafer. Using common microelectronic fabrication techniques, free-standing thin film specimens were produced that span rectangular windows in the wafer. The wafer was diced into individual tensile specimens composed of a thin film surrounded by a silicon frame. The final step before testing was to cleave the silicon frame so that the load was completely carried by the metal film. The ultimate tensile strength of the films was found to be approximately 150% greater than that of annealed bulk gold. In contrast, the measured elastic modulus for the thin film specimens was approximately the same as that documented for bulk gold.