bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dislocation Substructure in NiAl Single Crystals Deformed at Ambient Temperature
Authors: Shi X. , Pollock T. M. , Mahajan S. , Arunachalam V. S. 
Published: April 2011

ABSTRACTDislocation substructure in NiAI single crystals oriented for single slip and deformed at ambient temperature has been studied using weak-beam transmission electron microscopy. Deformation is localized in bands that consists mostly of near-edge dislocations, with an interspersion of a high density of elongated prismatic loops. Pure screw dislocations are not observed, but dislocations having “zigzag” configurations that are near-screw in orientation are present. A high density of jogs is observed on both near-edge and zigzag dislocation segments. The mechanisms for the development of this substructure are discussed, emphasizing the role of double cross slip and resulting glissile and sessile jogs of varying heights.
Creep Behavior of MoSi2 with Si3N4 Reinforcements
Authors: Feng C. R. , Sadananda K. 
Published: April 2011

ABSTRACTBecause of its high melting point, excellent oxidation resistance and ductility at high temperatures, MoSi2 and its composites are attractive for elevated temperature applications. In this study, the compression creep behavior of hot pressed MoSi2 with various volume fraction of Si3N4 at 1200°C, 1300°C and 1400°C were investigated. Within the stress range of 115–425MPa, the stress exponent, n, was either 1 or 5 depended on the volume fraction of Si3N4. The activation energy of creep for MoSi2-50%Si3N4 composite was 750kJ/mol. At still higher volume fraction of Si3N4, the activation energy decreases to 693kJ/mol, which is the same as that for monolithic Si3N4.
Nanometer-Scale Metal Dispersions in Polymeric Matrices
Authors: Shull K. R. , Cole D. H. , Rehn L. E. , Baldo P. 
Published: April 2011

ABSTRACTWe have investigated the diffusive properties of model metal nanoparticle dispersions in polymeric matrices of several different molecular weights. Rutherford Backscattering Spectrometry was used to measure the depth distribution of gold nanoparticles within thin layers of poly(t-butyl acrylate) (PTBA). The gold nanoparticles were created by evaporation of a discontinuous gold layer onto a thin film of PTBA. A second PTBA film was placed onto these samples to create “sandwiches” in which the gold existed between two PTBA films. Gold particle diffusion coefficients were obtained from measured gold particle depth distributions in annealed samples for which the molecular weights of the two PTBA layers were identical. The experiments revealed that particle mobility was decreased by two to three orders of magnitude compared with the predictions of the Stokes-Einstein model of particle diffusion. These results are attributed to bridging interactions between particles arising from slow exchange kinetics of polymer segments at the polymer/metal interface. Experiments for which the molecular weights of the two polymer films are different are sensitive to the ability of polymer molecules to pass through the gold particle layer. Experiments done with thermally evaporated particles are consistent with a picture in which polymer molecules are able to freely pass through the gold particle layer. Results obtained with gold deposited by electron-beam evaporation are strikingly different. The gold in this case is not able to diffuse, and polymer molecules are not able to penetrate the gold layer. These results, in addition to preliminary results from optical absorption experiments, indicate that much smaller particles are obtained by electron-beam evaporation than by thermal evaporation.
Morphology of a Blend of Zinc Neutralized Sulfonated Poly(Phenylene Oxide) or Polystyrene and an Amino Silicone
Authors: Jones Alan A. , Inglefield Paul T. , Yang Changlai , Bergquist Pamela , Shi Jiefeng , Kambour Roger P. , Wignall George D. , Migeon Henri-Noel , Martin Jean-Paul 
Published: April 2011

AbstractA polymer blend of an ionomer based on zinc neutralized sulfonated poly(phenylene oxide) or polystyrene with a silicone copolymer containing 6.45% propylamine groups in place of one of the methyl groups on a backbone silicon was prepared. Carbon-13 magic angle spinning spectra show coordination of the amine by the zinc ions. Morphological characterization was made by NMR spectroscopy based on proton spin diffusion, by small angle x-ray scattering and by energy filtered transmission electron microscopy. All experiments show domains in the range of 1 to 1000 nm and domain size can be controlled by the extent of coordination of the amine groups by the zinc ions and by thermal history. The different morphological experiments lead to an apparent hierarchy of domain sizes. The NMR experiment yields the smallest domains, 2 to 10 nm, where contrast is produced by differences in chain mobility. Small angle x-ray scattering indicates domains of 16 nm while electron microscopy indicates domains in the range of 100 to 1000 nm. The variation of the domain size between experiments may reflect the different sources of contrast in each case.
Lead and Silver Production in the Montevecchio Basin (Western Sardinia, Italy)
Authors: Ingo G.M. , Agus T. , Ruggeri R. , Amore Bonapasta A. , Bultrini G. , Chiozzini G. 
Published: April 2011

ABSTRACTLead slags and lead pieces, chronologically related to the Punic and Roman periods (IV BC - II AC), have been found at Bocche di Sciria, in the basin of the Montevecchio mine (south-western Sardinia, Italy). Furthermore, along the coast of this area over than 20 Punic and Roman shipwrecks with charges of lead ingots have been found. These materials indicate intense pyrometallurgical activities and the presence of metal production centres very close to the metal ore deposits. The microchemical studies of the slags have shown that they can be associated to a smelting process for lead and silver production. Furthermore, lead isotope analysis has been carried out for lead ores from Montevecchio and for the lead slags, litharge, lead pieces found there. The results for lead ores are in good agreement with literature and the scatter of data for slags, litharge and lead pieces suggest to rule out a lead isotope fractionation in ancient lead and silver production.
Hrtem Studies of Dislocations and Interfaces in TiAl
Authors: Mills M. J. , Wiezorek J. M.K. , Fraser H. L. 
Published: April 2011

ABSTRACTIn this paper, we summarize the results of high resolution transmission electron microscopy investigations of the structure of dislocations and interphase boundaries in Ti-Al alloys. Dislocations of the type 1/2<110] and 1/2<112] have been examined in 60° and 90° orientations, respectively, in single-phase Ti-52 at%Al. The former dislocation exhibits an extremely compact core configuration, suggesting a high complex stacking fault energy, while the latter is dissociated the scale of several nanometers in a coupled intrinsic/extrinsic stacking fault configuration. Two types of α2/γ interface structures have been observed in nearly fully-lamellar Ti-48 at%Al. The first is consistent with the common observation of structural ledges due to 1/6<112> dislocations in the interface plane. The second interface type consists of a quasi-periodic array of 1/2<110] dislocations which do not lie in the interface, and appear to be contained wholy within the γ phase. The possible implications of these observations with respect to the mechanical behavior of both single-phase γ and two-phase lamellar microstructures are discussed.
Time-Dependent Interfacial Reaction Mechanism in a Spinel-Forming Solid State Reaction Studied by TEM
Authors: Werner P. , Sieber H. , Huxebrand R. , Hesse D. 
Published: April 2011

ABSTRACTInterfacial reaction mechanisms were investigated in case of topotaxial formation of MgIn2O4 spinel on MgO crystals, which is an appropriate model system for thin film solid state reactions in ceramics. The reaction interface MgO/MgIn2O4(001), which is characterized by a large lattice misfit (+4.2%) between these cubic crystals, was investigated by transmission electron microscopy (TEM). Thin spinel films (thickness t< 0.5μm) consist of domains tilted off (≈3.5°) the exact cube-to-cube orientation into four directions, while thicker films (t> 1μm) show an accurate (001) orientation. High-resolution electron microscopy (HREM) showed that this time-dependent orientation behavior correlates with the atomic scale structure of the interface, especially with the different types of misfit dislocations. Based on these results, the misfit accommodation mechanism at the propagating reaction front in this spinel system is discussed including transitions between glide and climb processes.
Imaging the Dimers in Si (111) 7×7
Authors: Marks L. D. , Bengu E. , Plass R. , Ichimiya T. , Ajayan P. M. , Iijima S. 
Published: April 2011

ABSTRACTRecent work has demonstrated that high resolution electron microscopy in plan-view imaging mode is capable of directly imaging surfaces at a resolution of better than 2 Å. For the particular case of the Si (111) 7×7 surface, we have been able to image not only the adatoms visible in STM images, but all the atoms in the top three atomic layers including the dimers. The potential applications of this approach and its limitations will be discussed.
Application of Spatially Resolved Eels on Atomic Structure Determination of Diamond Grain Boundary
Authors: Ichinose H. , Zhang Y. , Ishida Y. , Ito K. , Nakanose M. 
Published: April 2011

ABSTRACTA new spatially resolved electron energy-loss spectrometry (EELS) method was introduced to obtain atomic structure information of grain boundaries in diamond thin films grown by chemical vapor deposition. The electron energy-loss spectra recorded from the grain boundary regions showed different feature near the energy loss corresponding to carbon ls-to-π* transition, as compared to the spectra recorded from neighboring crystalline regions. This difference was attributed to dangling bonds in atoms with planar three-fold coordination. A series of experiments are described in this paper that exclude any possible artifact in result interpretation.
Ring-Related Defects in MCZ Wafer Comparison by Electrical, Structural, and Device Properties
Authors: González F. , McQueen M. , Barbour R. , Rozgonyi G. A. 
Published: April 2011

ABSTRACTThermal cycles in advanced CMOS processing can nucleate an annular ring of oxygen precipitate-induced stacking faults (OSF-ring) via activation of bulk nuclei grown-in during the crystal pulling process. Because the OSF-ring can adversely affect device characteristics, it is important that substrates with OSF-ring characteristics be detected early in the process. Results are presented in this paper from a typical DRAM device which show that the ring can act either in a beneficial gettering mode or as a device-degrading zone, depending on the depth distribution of the OSF-ring defects and the background iron impurity concentration.
Modeling Silicon Implantation Damage and Transient Enhanced Diffusion Effects for Silicon Technology Development
Authors: Giles Martin D. , Yu Shaofeng , Kennel Harold W. , Packan Paul A. 
Published: April 2011

ABSTRACTDespite more than 20 years of effort, detailed understanding of defect-coupled dopant diffusion in silicon still falls short of what is practically required to support state-of-the-art silicon technology development. The challenge for modeling in industry is to combine the best of our physical understanding with measurements of dopant profiles for technology-relevant conditions to provide models which are as predictive and efficient as possible. This paper presents experimental results which provide insight into damage generation and annealing processes and discusses practical modeling approaches to support technology development despite our incomplete understanding of the physical processes involved.
Helium Induced Cavities in Silicon: Their Formation, Microstructure and Gettering Ability
Authors: Kaschny J. R. , Fichtner P. F. P. , Muecklich A. , Kreissig U. , Yankov R. A. , Koegler R. , Danilin A. B. , Skorupa W. 
Published: April 2011

ABSTRACTThe formation of cavity microstructures in silicon following helium implantation (10 or 40 keV; 1×1015, l×1016 and 5×1016 cm−2) and annealing (800 °C) is investigated by means of Transmission Electron Microscopy (TEM), Rutherford Backscattering Spectrometry and Channeling (RBS/C), and Elastic Recoil Detection (ERD). The processes of cavity nucleation and growth are found to depend critically on the implanted He concentration. For a maximum peak He concentration of about 5×1020 cm−3 the resulting microstructure appears to contain large overpressurized bubbles whose formation cannot be accounted by the conventional gas-release model and bubble-coarsening mechanisms predicting empty cavities. The trapping of Fe and Cu at such cavity regions is studied by Secondary Ion Mass Spectrometry (SIMS).
Chemical Trends in Electronic Properties of Gold-3D Transition Metal Impurity Pairs in Silicon
Authors: Justo J. F. , Assali L. V. C. 
Published: April 2011

ABSTRACTWe report theoretical investigations of the chemical trends in the electronic properties of substitutional gold-interstitial transition-metal complexes in silicon. The results show that the stable pairs in trigonal symmetry are formed by a covalent mechanism which includes, besides Au and TM impurities, also the Si neighbors, rather than being derived from interactions between two electrostatically bound point charges.
Oxygen Gettering and Thermal Donor Formation at Post-Implantation Annealing of Hydrogen Implanted Czochralski Silicon
Authors: Ulyashin A. G. , Bumay Yu. A. , Fahrner W. R. , Ivanovo A. I. , Job R. , Palmetshofer L. 
Published: April 2011

ABSTRACTThe effect of oxygen gettering by buried defect layers at post-implantation annealing of hydrogen implanted Czochralski (Cz) grown silicon has been investigated. Hydrogen ions were implanted with an energy of 180 keV and doses of 2.7.1016cm−2 into p-type Cz and for comparison into p-type float zone (Fz) Si. The samples were annealed at temperatures between 400 °C and 1200 °C in a forming gas ambient and examined by secondary ion mass spectrometry (SIMS) in order to measure the hydrogen and oxygen concentration profiles. Spreading resistance probe (SRP) measurements were used to obtain depth resolved profiles of the resistivity. The observed changes of the resistivity after post-implantation annealing of hydrogen implanted Cz and Fz Si can be explained by hydrogen enhanced thermal donor formation processes (oxygen or hydrogen related) and charges at the SiOx precipitates. The effective oxygen gettering in hydrogen implanted Cz silicon is attributed to hydrogen enhanced diffusion of oxygen to buried defect layers.
Influence of Underlayer and Encapsulation Process on Texture in Polycrystalline Silver Thin Films
Authors: Zeng Yuxiao , Zou Y. L. , Alford T. L. , DENG F. , Lau S. S , Laursen T. , Manfred Ullrich B. 
Published: April 2011

ABSTRACTThe texture in polycrystalline Ag thin films prepared by e-beam evaporation has been characterized by an x-ray diffraction technique as a function of underlayers and encapsulation temperatures. The Ag films deposited on Ti layers showed a strong <111> fiber texture with a fiber axis parallel to the film normal, whereas an almost random orientation was observed in the Ag films on Cr layers. This underlayer dependence of texture is associated with the lattice match between Ag and underlayer metal. In addition to <111> texture, the Ag films on Ti also exhibited a <511> texture component, which is the result of twinning of <111> -oriented grains. After the encapsulation process, the <111> texture in the Ag films on Ti was significantly improved, as evidenced by an increased (111) diffraction intensity and a slightly narrower space distribution of the texture along the fiber axis. The highly textured Ag films are expected to exhibit an improved electromigration resistance.
Polycrystalline ZnO- and ZnO:Al-Layers: Dependence of film stress and Electrical Properties on the Energy Input During the Magnetron Sputtering Deposition
Authors: Ellmer K. , Cebulla R. , Wendt R. 
Published: April 2011

ABSTRACTDoped and undoped zinc oxide fims are widely used as transparent window and contact layers in thin film solar cells. Up to now the role of film stress on the layer and solar cell properties was not investigated in detail. In this paper the influence of the energy input from the magnetron sputtering plasma on the structural and electrical layer properties was investigated. The energy input during the deposition could be varied by using a simultaneous RF- and DC-excitation at a fixed sputtering pressure. The energy and the density of the ions bombarding the substrate at floating potential have been measured by a plasma monitor and by a Langmuir probe. Plasma monitor measurements displayed the different plasma potentials and ion energies at a floating substrate. While the DC-discharge is characterized by low plasma potentials and low ion energies, the RF-mode shows up to 2.5 times higher ion energies of EAr++ ≈ 50 eV.The structural and electrical properties of doped and undoped ZnO-films, deposited with different RF/DC-power ratios can be explained by taking into account the different ion energies and densities during the deposition. Higher ion energies (RF-excitation) improve the structural quality and reduce the film stress, which decreases the specific resistance, both by a higher charge carrier mobility as well as higher carrier concentrations. The lowest resistivities and film stresses were ≈ 6–10-4 Ωcm and 0.5 GPa, respectively. Layers with different film stresses have been used to prepare CuInS2/CdS/ZnO-solar cells. Lower stress in the ZnO-films leads to higher cell efficiencies. For the first time, these results can explain why RF-sputtering is almost exclusively used for the window preparation of thin film solar cells.
The Microstructure and Electromigration Performance of Damascene-Fabricated Aluminum Interconnects
Authors: Besser Paul R. , Sanchez John E. , Field David P. , Anick Shekhar Pram , Sahota Kashmir 
Published: April 2011

ABSTRACTNovel metal deposition stack and damascene processing methods have been used to fabricate electrically isolated parallel arrays of 1.0 νm deep aluminum-alloy interconnect trenches varying in width from 0.5 μm to 16 μm. The grain size and crystallographic texture of the Al in these trenches has been characterized using transmission electron microscopy (TEM) and local electron backscattered diffraction (EBSD), respectively. Narrow lines (0.5 and 1.0 μm wide) have a bamboo microstructure, intermediate widths (2.0 μm wide) are nearly bamboo, and wide lines (4.0 μm and wider) are polycrystalline. The <111> texture of the lines degrades with decreasing linewidth. A secondary <100> component is demonstrated and its origin proposed. The electromigration reliability of the narrow damascene Al lines was measured, and the observed enhancement of damascene Al interconnects compared to conventionally-fabricated Al interconnects is correlated with the microstructure.
Microstructural Control of Amorphous Silicon Films Crystallized using an Excimer Laser
Authors: Viatella J.W. , Singh R.K. 
Published: April 2011

ABSTRACTThe results of experiments using two techniques for microstructural control of laser-annealed silicon thin films on SiO2 substrates are given. In the first set, photolithographically fabricated single-crystal silicon seed wafers in intimate contact with the silicon films are used to show that it is possible to control nucleation location during laser annealing. Laser energy density was varied from 250–450 mJ/cm2 and the resultant microstructure was characterized using transmission electron microscopy (TEM). It was found to consist of four distinct regions. Areas adjacent to the seed consisted of grains with dimensions ∼ 0.5 μm. The surrounding region consisted of larger (∼ 1 μm) rectangular grains. A third region was observed sporadically and consisted of large (∼ 1.5 μm) rectangular grains adjacent to the latter region. The fourth region occurred several microns away from the contact and consisted of a fine-grained microstructure. In the second set, fine mesh (19 μm) masks were used to selectively crystallize regions in laser-annealed films. The resultant microstructure was characterized using TEM and was found to consist of large (∼ 1.5 μm) edge grains with smaller (∼ 0.8 μm) grains just inside of the edge grains. A theoretical discussion is presented to explain the observed phenomena in both experiment sets.
Improvement of Grain-Growth and Surface Roughness in Laser-Crystallized Polycrystalline Silicon Films
Authors: Choi H.-S. , Park C.-M. , Jeon J.-H. , Min B.-H. , Han M.-K. 
Published: April 2011

ABSTRACTThe effects of nitrogen-radical treated amorphous silicon (a-Si) films on laser-crystallization behavior have been studied for the improvement of the grain-growth and the surface roughness. The radical treatments were performed by the rf (13.56 MHz) plasma-enhanced-chemical-vapor-deposition (PECVD) system with N2 gas before the laser-crystallization. The grain-size of the laser-crystallized polycrystalline silicon (poly-Si) film with 600 seconds of radical-treatment time was remarkably increased by the relaxation of solidification process caused by the possible evolution of solid phase SiNx compounds which shows the low thermal conductivity. The electrical conductivity at 30 °C was rather lager value of 3×10-5 Ω-1cm-1 than 1×10-5 Ω-1cm-1 of poly-Si without radical treatment, while the highly resistive SiNx compounds were formed. From the SEM images, the surface roughness was also improved by the selective etching of the 5%-water-diluted hydrofluoric (HF) acid on the grain boundaries which the SiNx compounds were well segregated into during the laser-crystallization.
Microstructure of and Crystal Defects in Nanocrystalline Tin Dioxide Thin Films
Authors: Pan X. , Zheng J.G. 
Published: April 2011

ABSTRACTNanocrystalline SnO2 thin films, prepared by electron beam evaporation from high purity SnO2 and post deposition annealing in air at 700°C with different times, were investigated using HRTEM. The films are composed of nanocrystalline SnO2 crystallites and pores. Many of the crystallites consist of crystal defects, such as crystallographic shearing planes (CSPs), dislocations and twin boundaries (TBs). Atomistic structures of these defects were investigated. These defects interact with each other, resulting in different configurations of crystallites. The local composition at CSP and TB steps at dislocation cores varies with the type of dislocations and CSPs and is different from the stoichiometric composition of SnO2. Thus, the electronic structure at these defects is different from that of the perfect SnO2.
Atomie and Electron Structure of Diamond Grain boundaries in a Polycrystalline Film
Authors: Ichinose Hideki , Nakanose Megumi , Zhang Yaogan 
Published: April 2011

AbstractA polycrystalline diamond film was grown on the polished surface of silicon substrate in H2-CO-O2 mixing gas. Atomic and electron structure of grain boundaries in the film was investigated by both high resolution electron microscopy and electron energy loss spectroscopy. CSL boundaries in the film showed characteristic feature in atomic structure; Σ 9 CSL boundary was parallel not to (221) plane but to (114) plane. A new line which correspond to π * state was found in addition to major σ * line in the EELS spectra of the boundary which contained three coordinate atoms. Observed π * line shows occurred change of a dangling bond (pz electron) to π state. No π * line appeared in the EELS spectra obtained from boundaries which contained no three coordinate atom such as (111) Σ 3 boundary.