bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structural Processes in Gold-Based Metallization During the Formation of Ohmic Contacts to GaSb
Authors: Piotrowska A. , Kańifiska E. , Guziewicz M. , Mizera E. , Dynowska E. , Lin X. W. , Rouvimov S. , Weber Z. Liliental , Kwiatkowski S. 
Published: April 2011

AbstractAnnealing behavior of Au, AuZn, and AuSb metallization on GaSb have been investigated by the combined use of RBS, XRD, TEM, and I-V characterization. The results give evidence that the thermally activated contact reaction strongly depends on the particular elements incorporated in the Au layer. Pure Au reacts with GaSb at 100°C. The addition of Zn to Au metallization increases the thermal stability of the metallization/semiconductor system to 200°C. Antimony, forming with gold the AuSb2 phase in metallization, provides the most stable ohmic contact system.
Low Resistivity Mo-W Alloy for A-Si Tft Gate Electrode
Authors: Hara Y. , Atsuta M. , Oka T. , Tsuji Y. , Ogawa Y. , Takemura M. , Ikeda M. , Suzuki K. 
Published: April 2011

AbstractAmong various requirements for the a-Si TFT-LCD gate electrode, low resistivity is becoming more emphasized with the increase of display size and information content as well as process feasibility. We have developed a low resistivity Mo-W alloy as a material for gate buslines.The Mo-W film was formed by DC magnetron sputtering using Ar or Kr as the working gas. The resistivity of the fabricated film was 16 μΩ-cm when deposited with Ar, and decreased to a value as low as 13 μΩ-cm with Kr, which was less than a half that of the conventional Mo-Ta film. Inverted staggered a-Si TFTs having Mo-W gate electrodes formed with Kr were fabricated, and good transfer performance with thermal- and electrical stability was obtained. The applicability of the new alloy to LCDs with large area and high resolution was shown.
Diffusion Barrier Property of Sputtered Molybdenum Nitride Films for Dram Copper Metallization
Authors: Park Jong-Wan , Lee Jeong-Youb 
Published: April 2011

AbstractDiffusion barrier property of sputtered molybdenum nitride films for DRAM copper metallization was investigated as a function of annealing temperature. Molybdenum nitride thin films on silicon remained stable upon annealing 650°C-30min, but h-MoSi2 and t-MoSi2 were formed after the heat treatment at 700°C and Mo5Si3 phase was formed at 850°C. Increasing the annealing temperature decreased the stress of the γ-Mo2N/Si film down to about 0.8×1010dyne/cm2 at 800°C due to the reduction of the intrinsic stress component. Copper films on silicon substrates separated by thin layers of molybdenum nitride remained stable during the heat treatment at 600°C, but they began to fail as a diffusion barrier after the heat treatment at 650°C, when molybdenum silicides and copper silicide were thought to be formed. On heating, Cu/γ-Mo2N/Si films were affected by thermal stress as due to the thermal expansion coefficient between copper and molybdenum nitride thin films. Furthermore, interlayer interactions between copper and silicon increased with increasing the annealing temperature. The interlayer reactions were investigated by Rutherford backscattering spectrometry, X-ray photoelectron spectrscopy and Nomarski microscopy.
Energy-Filtered Tem of Ag-Co Thin Films
Authors: Scott John Henry J. , Majetich Sara. A. 
Published: April 2011

AbstractTEM grids containing Ag65Co35 thin films were annealed under protocols corresponding to maximum giant magnetoresistance (GMR) response in thicker films. These films were examined using high resolution TEM, electron energy loss spectroscopy (EELS), and electron spectroscopic imaging (ESI), which revealed small (50 nm diameter) Ag particles and very small (approximately 2 nm diameter) clusters in a suspending matrix of Ag-Co alloy. Cobalt maps did not reveal individual cobalt clusters, indicating that if such clusters exist, they are smaller than the 1–2 nm resolution limit of the technique.
Embrittlement of Cracks at Interfaces
Authors: Thomson Robb , Emeritus  , Carlsson A. E. 
Published: April 2011

AbstractThis paper presents a synopsis of already published work for cracks on interfaces and new results on the effect of changing the chemistry of the atoms at the interface. Once the appropriate cut-off for the oscillatory singularity in the interface analysis is determined, the physics of the crack is determined in terms of an appropriate driving force for a particular event of interest, and a lattice resistance to the event. Analytic approximations are available for the driving forces, and the lattice resistance is determined on the basis of a block construction for the lattice. We show that for the case where the chemical bonding at the interface is different from that in the matrix, the same ideas are applicable, provided the different chemistry is incorporated correctly in the lattice resistance construction.
A Tight-Binding Model Beyond Two-Center Approximation
Authors: Wang C. Z. , Tang M. S. , Pan Bicai , Chan C. T. , Ho K. M. 
Published: April 2011

AbstractWe present a tight-binding model which goes beyond the traditional two-center approximation and allows the hopping parameters and the repulsive energy to be dependent on the bonding environment. We show that this model works well for metallic as well as covalent systems.
Formation Energy, Stress, and Relaxations of Low-Index Rhodium Surfaces
Authors: Filippetti Alessio , Fiorentini Vincenzo , Stokbro Kurt , Valente Riccardo , Baroni Stefano 
Published: April 2011

AbstractAb initio local-density- functional- theory calculations of formation energies, surface stress, and multilayer relaxations are reported for the (111), (100), and (110) surfaces of Rh. The study is performed using ultrasoft pseudopotentials and plane waves in a parallel implementation.
Valence-Band Offset at the Zn-P Interface Between ZnSe and III-V Wide Gap Semiconductor Alloys: A First-Principles Investigation
Authors: Bernardini F. , Nieminen R. M. 
Published: April 2011

AbstractWe present a first-principles calculation of the valence-band offset at the (001) interface between ZnSe and III-V lattice-matched alloys based on Al, Ca, In, P elements, namely Al0.5In0. 5P and Ga0.1n0.5P. Among the different possible interface geometries we have focused on the P-terminated alloy in contact with the Zn-terminated ZnSe crystal. The results of this study show the existence of a very low band offset at the abrupt interface, both for the ideal geometry and for the relaxed atomic positions. The investigation of the electronic interface band structure reveals the presence of a low-lying half-filled interface band related to the Zn-P bond.
Atomic Force And Scanning Electron Microscopy Of Corrosion And Fatigue Of An Aluminum-Copper Alloy
Authors: Kowal K. , DeLuccia J. , Josefowicz J.Y. , Laird C. , Farrington G.C. 
Published: April 2011

AbstractThe morphological features of 2024-T3 aluminum alloy were delineated using atomic force microscopy (AFM) during separate and combined actions of corrosion and fatigue.In-situ AFM corrosion studies in hydrochloric acid environments without mechanical deformation showed accelerated dissolution in the vicinity of second phase precipitates leading to intergranular corrosion. During fatigue in air, AFM images revealed steps along grain boundaries, as well as parallel extrusions and intrusions during the early stages of fatigue life. At later stages of mechanical deformation persistent slip bands (PSBs) were observed on the sample's surface. Cracks were observed to nucleate and propagate along PSBs. For experiments where samples were subjected to the simultaneous action of a corrosive environment and mechanical deformation, intergranular cracking was observed during the early stages of fatigue life. The corrosive environment was observed to accelerate the crack nucleation process.
The Roles Of Atomic-Scale Dynamics And Structure In The Brittle Fracture Of Silica
Authors: Swiler Thomas P. , Varghese Tansen , Simmons Joseph H. 
Published: April 2011

AbstractWe modeled the initiation of fracture in vitreous silica at various strain rates using molecular dynamics simulations. We avoided biasing the location for fracture initiation within the sample so that we could study the effects of dynamics and structure on determining the path to fracture, defined as the particular bonds that break during the course of fracture. We sought to show that the path to fracture would be primarily determined by the local variations in the structure of the vitreous phase at low strain rates, with diminished sensitivity on structural variations at higher strain rates. However, the results of our model indicate that the path to fracture is dependent not only on the initial structure of the system and the applied strain rate, but also on the initial phase of the thermal vibrations. This underscores the importance of atomic dynamics in determining the path to fracture in brittle materials and provides a justification for extending the analysis of fracture surfaces to the near-atomic scale.
Fracture Process Control For A Peel-Apart Imaging Film
Authors: Choi H.-C. , Kniazzeh A. , Habbal F. 
Published: April 2011

AbstractPeeling delamination and image-layer fracture of a multilayer imaging film is analyzed by a simple beam approximation. Criteria for propagation of the delamination cracks and tensile failure of the imaging layer are established. The critical role of substrate strain in controlling tensile strain in the imaging layer is explored. For the case of a thin imaging layer with a fracture strain below a critical level, image layer fracture occurs while the leading-edge delaminations length is comparable to the layer thickness. Experimental Helios film image quality is optimized at a small level of substrate tensile strain where delamination length at leading and trailing edges of small holes is balanced and small and where hole size is minimized.
Cooperative Dislocation Generation And The Brittle-To-Ductile Transition
Authors: Khantha M. , Pope D. P. , Vitek V. 
Published: April 2011

AbstractThe characteristic features of the brittle-to-ductile transition are explained using a model of cooperative dislocation generation. In two dimensions, the onset of the ductile behavior corresponds to a thermally-driven, stress-assisted dissociation of many atomic-size dislocation dipoles in the vicinity of the crack tip above a critical temperature Tc. The instability is caused by thermally induced screening of dislocation interactions as in the Kosterlitz-Thouless phase transition. However, the critical temperature is well below the melting temperature in the presence of a stress. The nature of dislocation dynamics in the vicinity of the crack tip is also described and its role in the onset of the cooperative instability is examined. The origin of the correlation between the strain-rate dependence of the transition temperature and the temperature dependence of dislocation mobility is explained.
Structures of New Nitrides Prepared using Solid Oxide Precursors
Authors: Houmes Joel D. , Bem David S. , Loye Hans-Conrad Zur 
Published: April 2011

ABSTRACTSeveral novel transition metal nitrides and oxynitrides were synthesized via ammonolysis of solid state oxide precursors at temperatures ranging from 700°C-900°C and reaction times ranging from 12 hours to 4 days. The products were characterized by powder X-ray diffraction and their structures were determined by powder X-ray Rietveld refinement. The relationships between the structures of these nitrides and oxynitrides, and their similarity to the structures of the transition metal dichalcogenides, is discussed.
Spins, Phonons, and Hardness
Authors: Gilman John J. 
Published: April 2011

ABSTRACTIn crystals (and/or glasses) with localized sp3 or spd-bonding orbitals, dislocations have very low mobilities, making the crystals very hard. Classical Peierls-Nabarro theory does not account for the low mobility. The breaking of spin-pair bonds which creates internal free-radicals must be considered. Therefore, a theory based on quantum mechanics has been proposed (Science, 261, 1436 (1993)). It has been applied successfully to diamond, Si, Ge, SiC, and with a modification to TiC and WC. It has recently been extended to account for the temperature independence of the hardness of silicon at low temperatures together with strong softening at temperatures above the Debye temperature. It is quantitatively consistent with the behaviors of the Group IV elements (C, Si, Ge, Sn) when their Debye temperatures are used as normalizing factors; and appears to be consistent with data for TiC if an Einstein temperature for carbon is used. Since the Debye temperature marks the approximate point at which phonons of atomic wavelengths become excited (as contrasted with collective acoustic waves), this confirms the idea that the process which limits dislocation mobility is localized to atomic dimensions (sharp kinks).
Effect of Boron on Polytype Phase Transformation Occurring During Sintering of Si-C-B Powders Obtained By Combustion (SHS)
Authors: Gierlotka S. , Stel'makh S. , Palosz B. 
Published: April 2011

ABSTRACTSilicon carbide powders were synthesized by SHS method with boron added in various quantities as either amorphous elemental or boric acid additive. The powder samples were then heat treated at a selected temperature (up to 22000°C). Crystallographic structure of the powders were analyzed by means of X-ray powder diffraction technique. It was found that boron added in the form of H3BO3 tends to precipitate in the form of small clusters and does not dissolve evenly in the SiC lattice. Upon annealing the boron clusters dissociate. The boron atoms diffusing across the SiC lattice generate a large number of stacking faults with simultaneous transformation of hexagonal polytype 6H (α-phase) present in as-synthesized powders into the cubic 3C (βphase) modification.
Phase and Disorder Investigations in Boron Nitride Thin Films Grown by Pecvd
Authors: Depero L. E. , Sangaletti L. , Schaffnit C. , Rossi F. , Gibson P. N. 
Published: April 2011

ABSTRACTBased on X-ray diffraction and infrared spectroscopy measurements, BN thin films grown by PECVD on silicon substrates have been studied with the aim of identifying the thin film phase. In a set of samples, while the infrared spectra showed characteristic bands of the hexagonal phase, X - ray diffraction patterns only displayed reflections belonging to the cubic BN phase. Therefore, structural models have been developed to explain the apparent inconsistency between the two sets of experimental data. In particular, static disorder effects - which have been introduced in the model starting from the sp2 hybridization of the ordered hexagonal phase, as suggested by the infra-red spectroscopy results - allowed a consistent interpretation of the X-ray diffraction patterns. For another set of samples, which also showed a characteristic hexagonal signal in the IR data, the XRD pattern could not be indexed with any of the BN phases. In this case, the presence of molecular and ionic phases, associated with impurities, was considered in structural modeling studies.
Microstructural Development to Toughen Sic
Authors: Moberlychan W. J. , Cannon R. M. , Chan L. H. , Cao J. J. , Gilbert C. J. , Ritchie R. O. , De Jonghe L. C. 
Published: April 2011

ABSTRACTSiC offers a promise for high strength applications at high temperature; however, poor fracture resistance has inhibited its utility. Recent developments to control microstructure during hot pressing have improved fracture toughness >3 fold, while also improving strength 50% above that of a commercial SiC, Hexoloy. This ABC-SiC (designated for the Al, B, and C additives) utilizes liquid phase sintering to obtain full densification at 1650°C, and to induce the β-3C to α-4H phase transformation below 1900°C. Interlocking, plate-like, α grains, coupled with a thin (˜1 nm) amorphous layer, provide for tortuous intergranular fracture and high toughness.This study focuses on the developing microstructure; how the α-4H polytype grows as a stacking modification of the β-3C grains, and how amorphous grain boundaries and crystalline triple point phases develop and interact with the crack geometry. HR-TEM and Image-Filtered EELS characterize the amorphous grain boundaries. Field Emission - SEM, EDS and Auger Electron Spectroscopy characterize the fracture morphology and the chemistry of grain boundaries and triple points. Electron Diffraction and HR-TEM depict an epitaxial relationship between triple point phases (Al8B4C7 and A14O4C) and matrix α-SiC grains, the development of which affects the mechanical toughening. The transformation to toughen SiC is compared to the well-studied transformation processing in Si3N4. A distinct advantage is the interlocked nature of the plate-like grains which causes strong elastic bridging behind the crack tip.
Preparation of Polycrystalline Cds Thin Films by Chemical Bath Deposition
Authors: Lee Eun A , Kim Bum-Soo , Shin Sung Ho , Park Jung Il , Park Kwang Ja 
Published: April 2011

ABSTRACTWe prepared CdS thin films from a solution containing cadmium acetate, thiourea, ammonia, and ammonium acetate. We varied fabrication conditions such as the concentrations of reactants, reaction temperature, and heat treatment, to investigate the changes in structural and optical properties of the film. Effects of substrate on the properties were also investigated.
Atmospheric Pressure Chemical Vapor Deposition of Titanium Nitride from Titanium Bromide And Ammonia
Authors: Gordon Roy G. , Frisbie Ross W. , Musher Joshua , Thornton John 
Published: April 2011

ABSTRACTTitanium nitride films were formed by chemical vapor deposition from titanium tetrabromide and ammonia at atmospheric pressure and substrate temperatures from about 400 to 600 °C. Although titanium tetrabromide is a highly hygroscopic solid at room temperature, it can be handled conveniently as a very concentrated liquid solution (85 weight percent) in bromine as a solvent. This solution can be vaporized by a direct liquid injection system. Alternatively, the solution can be pumped into a bubbler, from which the bromine solvent is then removed by fractional distillation. Rutherford Backscattering Spectroscopy was used to determine that the bromine content of TiN deposited at 500°C was about one atomic per cent. Growth rates were about 17 nm/min, and electrical resistivity was found to be about 200 μΩ-cm.
Deposition And Characterization Of Silicon And Carbon Nitride
Authors: Myers A. F. , Tucker D. A. , Bozeman S. P. , Camphausen S. M. , Powers M. J. , Bruley J. , Hren J. J. , Cuomo J. J. 
Published: April 2011

ABSTRACTWe attempted to deposit carbon nitride films on flat Si (111) substrates and on sharp <111>-oriented silicon needles in a radio frequency (rf) inductively coupled plasma system utilizing a graphite source and a nitrogen plasma. The resultant polycrystalline films were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Auger electron spectroscopy (AES), and electron energy loss spectroscopy (EELS). Both selected area electron diffraction (SAED) and lattice imaging were used to identify and characterize the particles, which grew as faceted crystals up to 1 Rm in size. From SAED, high resolution TEM, and EELS, it was found that the particles on the Si needles were α-Si3N4 and that those on the Si wafer were mostly β-Si3N4 and β-C3N4, with some β-C3N4 possible. Auger quantitative analysis suggests that β-C3N4 could be stabilized by the presence of silicon, resulting in a material with compositions CxSiyNz.
CVD Growth of SiC on Ultrathin SOi2: A Step Towards Development of a Compliant Substrate for SiC and III-V Compounds
Authors: Namavar Freydoon , Colter P. , Cremins-Costa A. , Gagnon E. , Perry D. 
Published: April 2011

ABSTRACTThis paper addresses the initial stage of epitaxial growth of SiC on thin (about 300A) and thick (2000Å) Si films. Our results as obtained by Rutherford backscattering spectroscopy (RBS), Auger spectroscopy, and plan-view/cross-sectional TEM, demonstrate epitaxial growth of 3C-SiC structures on ultrathin Si films (even under non-optimized growth conditions). These preliminary results indicate that the crystalline quality of SiC on thin SIMOX is better than that grown on thick SIMOX or bulk Si substrates. Growth of SiC epi on thin Si will pave the way for growth of SiC directly on SiO2 (a compliant substrate) by carbonization of the entire thin Si top layer of SIMOX.
Oxidation Studies of Silicon Oxynitride Using X-Ray Photoelectron Spectroscopy and Transmission Electron Microscopy
Authors: Manessis D. , Du H. , Singer I. L. , Larker R. 
Published: April 2011

ABSTRACTSilicon oxynitride (Si2N2O) ceramics were oxidized in 1 atm dry oxygen at 11 00IC and 13000C. The oxidized samples were studied using x-ray photoelectron spectroscopy and crosssectional transmission electron microscopy in conjunction with energy dispersive x-ray analysis. TEM characterization revealed the chemical abruptness of the SiO2 and Si2N2O interface. Further investigation indicated the inclusions of residual SiO2 in Si2N2O, which contributed to the broad XPS elemental distribution in the oxide-substrate interface region.
Unimolecular Precursors to Binary Metal Sulfides: Mechanistic and Structural Correlations
Authors: Schluter Rodney D. , Kräuter Gertrude , Rees William S. 
Published: April 2011

ABSTRACTThe roles which ligand size and stability play in influencing solid-state thermolyses products and phases are developed for a group of metal thiolate compounds. The exploration includes Pb(SR)2 [R = t-Bu, i-Bu, s-Bu], Cd(SR*)2 [ R* = i-Pr, I-Bu, Bz], ClHgSR** [ R** = i- Pr, neo-Pent, Bz] and In(SR***)3 [R*** = 2,4,6-(i-Pr)3C6H2, 2-CH3O-5-CH3C6H3, o- C6H4CH2N(CH3)2]. In several examples, the precursors have been characterized by single crystal X-ray diffraction. In most cases, solid-state decomposition products have been identified by XRPD, and volatile decomposition products have been identified by GC/MS. All precursors have been studied by TGA.
A Novel Self-Assembled Collagenous Matrix which Serves as a Template for Oriented Growth of Hydroxyapatite Crystal
Authors: Christiansen D. L. , Pins G. D. , Huang E. K. , Silver F. H. 
Published: April 2011

AbstractCollagen fibers self-assembled from solutions of molecular type I collagen were mineralized at pH 9.5, by exposure to super-saturated solutions of calcium and phosphate for a one week period in a double diffusion chamber. Uniaxial tensile mechanical properties increased with mineralization and electron microscopy of the mineral formed within the fiber was morphologically similar to the mineral phase of calcified tissues. Selected area electron diffraction confirms the presence of hydroxyapatite crystal. Further, the aligned fibrillar substructure serves as a template for the orientation of the c-axis diffraction maxima of the hydroxyapatite. These results indicate that an aligned system composed exclusively of selfassembled type I collagen fibrils serves as a scaffold for oriented growth of mineral analogous to calcification in vertebrate bone.
Polystyrene Surfaces Terminated with a Single Functionality of Alcohol
Authors: Sun J.Q. , Bello I. , Lau W.M. , Lipson R.H. , Lin Z.D. 
Published: April 2011

AbstractPolymer surfaces terminated with a specific chemical functionality are attractive for biomaterial applications because of the predictability and selectivity of surface reactions towards the anchoring of a biochemical agent to the polymer. In the present work, engineering of surface functionality was performed using OH radicals generated in gas phase by the reaction between a hot filament and water molecules in vacuum. The generation of OH was confirmed by laser induced fluorescence spectroscopy. The incorporation of oxygen and formation of alcohol groups on polystyrene were confirmed by x-ray photoelectron spectroscopy. High resolution electron energy loss spectroscopic data also showed that for polystyrene with an uptake of less than a monolayer equivalent of oxygen, C-OH was the only detectable surface functionality containing oxygen.