bluuebunny/crossref_metadata_2025_split huggingface dataset:
Flux Line Dynamics with Electron Holography
Authors: Tonomura Akira 
Published: April 2011

ABSTRACTFlux lines in superconducting thin films are observed statically in a holographic electron interference micrograph, and dynamically in a Lorentz micrograph with a “coherent” and 300kV electron beam. In interference microscopy, projected magnetic lines of force in a tilted Nb thin film are observed quantitatively as contour fringes drawn on an in-focus electron micrograph. Whereas in Lorentz microscopy, flux lines are observed as spots with bright and dark contrast pairs due to defocusing of the image. Although the image is blurred due to a large amount of defocusing, this method is suitable for real-time observation. By making the best use of this feature, flux line movement can be observed when the applied magnetic field or the film temperature changes.
Calculation of Stresses in Strained Semiconductor Layers
Authors: Nakajima K. 
Published: April 2011

ABSTRACTA stress calculation method is proposed by improving the force and moment balance method to calculate the stress in semiconductor layers. The following three points are improved. The first point is that the vertically precise stress distribution in multilayers can be calculated by using imaginary thin layers. The second point is that the stress can be calculated on the basis of threedimensional deformation. The third point is that the stress can be calculated in strained layers with interfacial misfit dislocations. The stress distribution in strained semiconductor layers such as InGaAs/GaAs multilayers, InGaAs/graded lnGaAs/GaAs layers and GaAs/Si structures is calculated using this improved method.
X-Ray Spectrometer with a Submicron X-Ray Beam for Ulsi Microanalysis
Authors: Yamamoto Naoki , Homma Yoshio , Sakata Shinji , Hosokawa Yoshinori 
Published: April 2011

ABSTRACTA fluorescent and diffraction X-ray spectrometer with a 0.8 μmϕ Xray beam has been developed. It allows simultaneous measurement of local strains and minute amounts of metal contaminants in fine ULSI devices. The minimum sample size for X-ray diffraction measurement with it is a 0.3 μm diameter by 0.2 μm deep volume. It is applied to analyze strain in Al lines, showing that strain in Al single-layer lines (no barrier) increases significantly as the line width is reduced below 1.5 μm. Introducing barrier metals reduces this dependence of strain on line width. It is also found that hillock and void formation has a very strong correlation to strain.
Measurement and Interpretation of Strain Relaxation in Passivated Al-0.5%Cu Lines
Authors: Besser Paul R. , Marieb Thomas N. , Bravman John C. , Flinnt Paul A. 
Published: April 2011

ABSTRACTX-ray diffraction was used to measure the strain relaxation in passivated Al-0.5%Cu lines at 200°C after cooling directly from an anneal at the passivation deposition temperature. The strain decay is fit with a stress-assisted, thermally-activated relaxation model. A high-voltage scanning electron microscope was used to image the presence and growth of voids through the passivation. The time scale of the void growth is not the same as that of the hydrostatic relaxation, indicating that voiding is not solely responsible for the observed relaxation. The relaxation of the line is modeled using a von Mises yield criterion and allowing elastic compliance of the passivation. The magnitude of the calculated relaxation agrees with the measurements. It is suggested that a combination of voiding and passivation compliance is responsible for the measured hydrostatic strain relaxation.
Electromigration Lifetimes of Single Crystal Aluminum Lines with Different Crystallographic Orientations
Authors: Joo Y.-C. , Thompson C.V. 
Published: April 2011

ABSTRACTNear-bamboo interconnects are susceptible to failure either at polygranular clusters or within bamboo grains (transgranular failure). Polygranular failure mechanisms are often dominant in lines with near-bamboo structures at test conditions, but at service conditions, transgranular failure mechanisms are expected to dominate. In order to study the temperature and current density dependence as well as the crystallographic dependence of these transgranular failure mechanisms, it is necessary to isolate them from other mechanisms. To do this, we have studied single crystal Al lines on oxidized silicon.We have tested lifetimes of passivated and unpassivated Al single crystal lines with various textures. In both passivated and unpassivated lines, the median time to failure, t50, was found to be texture-dependent, with t50(l11) > t50(133) > t50(110), and with t50(111) ∼ 10×t50(110). The activation energy for failure for both passivated and unpassivated (110) single crystal lines was about 1 eV. This value differs from that of aluminum bulk diffusion (1.4 eV), suggesting that interface diffusion is the dominant diffusion mechanism in these lines, and perhaps in bamboo regions of near-bamboo lines as well.
Stress Distribution and Mass Transport Along Grain Boundaries During Steady-State Electromigration
Authors: Scherge M. , Bauer C. L. , Mullins W. W. 
Published: April 2011

ABSTRACTStress distribution and mass flux in the plane of each grain boundary within a polycrystalline thin-film conductor have been calculated during electromigration for zero flux divergence (steady state) and various boundary conditions. Steady state, representing a balance between the (applied) electric and (induced) stress driving forces, is assumed to develop after a short transient time. Boundary conditions at the intersection of grain boundaries with the top and bottom conductor surfaces (surface junctions) and with the conductor edges (edge junctions) are assumed to be of two types: open (flux passes freely) and closed (zero flux). Flux is assumed to pass freely at the intersection of grain boundaries with each other (triple Junctions). Several grain boundary configurations are considered, including individual boundaries, single triple junctions, and combinations thereof, assuming that bottom surface junctions (conductor/ substrate interface) are closed and that top surface junctions are either open (bare conductor) or closed (passivation layer). Results clearly show the formation of incipient holes and hillocks near the intersection of triple junctions and/or closed (blocked) edge junctions with open surface junctions.
Early Electromigration Failure in Submicron width, Multilayer Al Alloy Conductors: Sensitivity to Stripe Length
Authors: Oates A. S. 
Published: April 2011

ABSTRACTThe microstructure of Al alloy integrated circuit conductors strongly affects electromigration failure of the metallization. For submicron linewidths, the microstructure is usually near - bamboo, consisting of alternate polycrystalline and bamboo segments. These polycrystalline segments appear to be much more susceptible to electromigration - induced voiding than the bamboo regions. As a result, microstructural related early failures are a significant concern. In this study we systematically vary line - length to investigate the impact of random microstructural variations on the failure distribution parameters of narrow, multilayer (Ti/TiN/Al/TiN) Al alloy conductors. We show that early failures can occur in 0.6 μm wide stripes. The impact of early void formation on conductor failure, however, is dependent on the resistance failure criterion. By increasing the value, early failures may be eliminated in long line - lengths, suggesting that the resistance failure criterion may provide a means to control the impact of early voiding on the electromigration failure.
Large Area Pulsed Laser Deposition of YBCO Thin Films and Buffer Layers on 3-Inch Wafers
Authors: Lorenz M. , Hochmuth H. , Börner H. , Natusch D. , Kreher K. 
Published: April 2011

AbstractAn arrangement for large area PLD on 3-inch wafers is proposed. In order to get a homogeneous stoichiometry and thickness distribution and small variations of superconducting properties on the 3-inch diameter, the substrate is foreseen to be rotated and additionally laterally moved up to 45 mm during deposition whereas the laser plume remains fixed.YSZ buffer layers showed thickness homogeneity of 1% within 10 mm, of 4% within 2 inch and of 8% within 3 inch diameter, respectively. For in-situ deposited YBCO thin films on r-plane sapphire with YSZ buffer layer we inductively measured within 3 inch diameter values of the critical temperature Tc(90%) from 85.9 K to 86.7 K and values of the critical current density jc(77 K) from 1 × 106 to 2 × 106 A/cm2. However, up to now the degree of epitaxy of the YBCO thin films on r-plane sapphire with YSZ buffer layer is lower compared to YBCO on MgO(100) as determined by Raman spectroscopy. Nevertheless, large area PLD seems to be a very promising technique for homogeneous coating of 3-inch wafers by epitaxial oxide thin films.
Cluster Models for Point Defect Structure in La2CuO4+δ
Authors: Wu Yue , Ellis D. E. , Mason T. O. 
Published: April 2011

AbstractWe report theoretical studies on oxygen excess defect structure of lanthanum cuprate, La2CuO4+δ, using the Local Density formalism. The self-consistent Discrete Variational method has been used to find energy levels, densities of states, charge transfer, wavefunctions and potentials for a fragment consisting of N atoms embedded in the infinite crystal. Various possible interstitial oxygen positions and relative stability have been studied, including the structure suggested by Chaillout, et al. on the basis of neutron diffraction. Calculated electronic structures have been used to predict defect-related spectroscopic consequences.
Applications of Nonlinear Optical Thin Films
Authors: Brueck S. R. J. , Myers R. A. 
Published: April 2011

AbstractMany approaches to fabrication of nonlinear optical and electro-optical thin-film materials are currently under investigation including: epitaxial inorganic films; polycrystalline inorganic materials; organic nonlinear moieties poled in polymer hosts; and poled amorphous inorganic materials. For each of these approaches there are a variety of characteristics and constraints that impact the ultimate uses. These are discussed in the context of signal processing and transmission applications such as optical interconnects and integrated optics. Almost universally, integration with the Si materials and processing that dominates current computer technology, or with the III-V materials that dominate optoelectronics technology, are major factors in the attractiveness of a technology direction. A relatively recent development is the observation of a strong nonlinearity in fused silica, χ(2) ∼ 1 pm/V, poled by modest temperature and electric-field stress. Temperature-dependent dynamic and spectroscopic measurements suggest that mobile-ion species such as Na+, as well as non-bridging oxygen bond re-orientation under a strong field, play a role in the nonlinearity.
Raman Spectroscopy of Barium Titanate Thin Films
Authors: Robins Lawrence H. , Kaiser Debra L. , Rotter Lawrence D. , Stauf Gregory T. 
Published: April 2011

AbstractRaman spectroscopy was used to examine the structure of polycrystalline and epitaxial barium titanium oxide thin films grown by metal-organic chemical vapor deposition. The Raman spectra confirmed the presence of the tetragonal ferroelectric phase of BaTiO3 and also revealed several other Ba-Ti-O phases. These films were also characterized by X-ray diffraction and TEM imaging. The structural information provided by the Raman spectra was qualitatively consistent with the X-ray and TEM results. The temperature dependencies of the Raman spectra of two films were examined in the range 25°C-175°C. Raman peaks due to tetragonal BaTiO3 were observed at temperatures well above 132°C, which is the tetragonal-cubic phase transition temperature for bulk single-crystal BaTiO3. This may indicate stabilization of the tetragonal phase by an anisotropic film-substrate interaction or by inter-grain stresses.
Incorporation of Iron Cations Into Epitaxial Sapphire Thin Films by CO-Evaporation and Subsequent Thermal Annealing
Authors: Yu Ning , Kung Harriet , Nastasi Michael , Li DeQuan 
Published: April 2011

AbstractIron-doped sapphire thin films have been successfully epitaxially grown onto sapphire single crystal substrates by electron beam deposition and subsequent thermal annealing. Amorphous A12O3 thin films, about 280–390 nm thick, cation doped with iron have been deposited on [0001] oriented sapphire substrates. Iron doping with cation concentrations (a ratio of Fe content to total cation content) up to 5 at.% can be incorporated into the octahedral sites of Al-cation sublattice during the epitaxial regrowth process at 1000–1400 C, as determined by Rutherford Backscattering Spectrometry and ion channeling measurements. Cross-sectional Transmission Electron Microscopy shows the presence of two distinct regions in the annealed films. One exhibits the epitaxial relationship with the sapphire substrate and the second region has amorphous type of contrast. External optical transmittance measurements in the ultra violet and visible light range have exhibited the absorption associated with Fe3+. This study has demonstrated a simple method of incorporating dopants into single crystal sapphire, which has potential in the fabrications of thin film planar optical waveguiles.
In-Situ Thin Film Growth of PbTiO3 By Multi Target Sputtering
Authors: Maeder Thomas , Muralt Paul 
Published: April 2011

AbstractThe in-situ reactive sputter deposition of PbTiO3 on Pt/Ti/SiO2/Si from two metallic targets was investigated. A minimal lead oxide flux of two to three times the titanium oxide flux is needed in order to obtain stoichiometric films with the perovskite structure. For higher fluxes, the Pb/Ti ratio in the film stays at the stoichiometric value 1; the orientation changes from random to <100>; and the film morphology transforms from a rough to a smooth polycrystalline film. The obtained dielectric constants vary between 40 and 150, the losses between 2 and 4 % (10 kHz). The method could be extended to PbZrxTi1-xO3 for x ≤0.7. The orientation is lost when the Pt electrodes are replaced by RuO2 electrodes.
Catalytic Combustion for Ultra-Low Emissions
Authors: Farrauto Robert J. , Larkin Matthew , Fu James , Feeley Jennifer 
Published: April 2011

AbstractCatalytic combustion is an emerging technology in which fuels can be combusted homogeneously supported by a catalyst. The catalyst allows non-flammable mixtures of fuel and air to be oxidized with the resulting heat generated used to initiate thermal or homogeneous combustion. With the proper catalysts the fuel can be combusted with efficiencies so high that unburned CO or HC emissions are less than 10 ppm. Furthermore, because the fuel-air mixtures are relatively lean compared to conventional processes the adiabatic temperatures are below that required for the formation of NOx i.e. > 1500°C. The success of this technology would eliminate the need for expensive after-treatment of emissions from gas fired power plants and boilers.This is a very demanding application, especially for natural gas fueled combustors, since the catalyst will have to initiate reaction between 400 and 500°C, at linear velocities exceeding 50 ft/sec, and retain its activity after experiencing temperatures up to 1400°C. Furthermore, the monolithic ceramic or metallic support upon which the catalyst is deposited must also retain structural integrity after experiencing high temperatures and severe thermal shock.This paper will describe the fundamental concepts of this new technology, the major technical problems being addressed and the progress being made.
Environmentally Conscious Materials and Manufacturing Processes
Authors: Narayan C. , Fenton J. , Datta M. 
Published: April 2011

AbstractEnvironmental and safety issues are becoming increasingly critical for the selection of materials and their processing techniques. While the choice of “green” materials is important from the perspective of disposal of spent or used products, the choice of environmentally sound processes is important to cut down manufacturing waste and limit the use of toxic solvents and solids. Some examples from the electronics and the aerospace industry are described.
Catalytic Decomposition of N2OON ZrO2and Co/Ni/ZrO2Systems
Authors: Zeng H. C. , Lin J. , Teo W. K. , Wu J. , Tan K. L. 
Published: April 2011

AbstractMonoclinic ZrO2and its supported catalysts Co/Ni/ZrO2for catalytic decomposition of N2O have been studied with FTIR, EDAX, XPS, and the evaluation of activity of the catalysts. It is found that monoclinic ZrO2alone has the catalytic effect for N2O decomposition although the gas decomposes on Co/Ni/ZrO2more efficiently. The XPS study shows that only Co exists in the surface region of ZrO2. In evaluation experiments, it is found that when Co/Ni exceeds a threshold concentration, the conversion of N2O is no longer accelerated with the increase of Co/Ni content. The gas decomposition on Co/Ni/ZrO2can be described as first order with respect to partial pressure of N2O. No nitrogen N(ls) photoelectrons were detected for the catalysts after N2O decomposition. Surface reactions on ZrO2and Co/Ni/ZrO2, including the behaviour of retained carbon (Cls) and N2O decomposition mechanism, will also be addressed.
Biosurfactant Production Using Mixed Cultures Under Non-Aseptic Conditions
Authors: Vipulanandan C. , Ghurye G. L. , Willson R. C. 
Published: April 2011

AbstractSurfactants increase the accessibility of adsorbed hydrocarbons and mobilize immiscible petroleum hydrocarbons for treatment. Biosurfactants have the advantage of biodegradability and non-toxicity over their synthetic counterparts, and can be produced from renewable sources. In this study the production of biosurfactant from molasses was investigated in continuously stirred batch reactors. The effects of substrate concentration, yeast extract and peptone on biomass accumulation and biosurfactant production were investigated. Biosurfactant production was quantified by surface tension reduction and critical micelle dilution (CMD). Biosurfactant production was directly correlated with biomass production, and was improved with the addition of yeast extract. Centrifugation of the whole broth reduced surface tension. The performance of the biosurfactant produced from molasses under non-aseptic condition is comparable to other published results.
Laser Cleaning - A New Surface Cleaning Method Without Pollutions
Authors: Lu Y. F. , Aoyagi Y. 
Published: April 2011

AbstractSurface contaminations are removed by laser irradiation with pulse output and short wavelength from various substrate such as magnetic head slide, glass and metals. Laser cleaning is a new dry process to remove surface organic contaminations without using ultrasonic cleaning in organic solvents. This provides a new dry process to clean different substrate surfaces and can take the place of conventional wet cleaning processes such as ultrasonic cleaning with CFC and other organic solvents. The mechanisms of laser cleaning may include laser photodecomposition, laser ablation and surface vibration due to the impact of laser pulse. It is found that short wavelength and short pulse duration are necessary for effective cleaning. It is also found that an appropriate energy density is critical to achieve effective cleaning without causing surface oxidation and secondary contamination.
Solid Freebody Forming of Ceramics from Polymerizable
Slurry
Authors: Stuffle Kevin , Mulligan Anthony , Lombardi John , Calvert Paul , Fabes Brian 
Published: April 2011

ABSTRACTA system is described for forming three-dimensional parts from a
polymerizable slurry. This liquid is delivered from a fine nozzle to build
up the component as a series of layers described from a CAD drawing of the
part. This is one of a family of solid freebody forming methods. The
layerwise process lends itself particularly to chemically syntheized
materials where shrinkage and mass transport are major problems. The
technique also has considerable potential for combining various materials
into a single component.
Cycloaliphatic Epoxide Based Sol-Gel Derived
Materials
Authors: Sigel G. A. , Domszy R.C. , Welch W. C. 
Published: April 2011

ABSTRACTScratch resistant transparent organically modified sol-gel materials
typically utilize organics as acrylates, or pre-polymer silicon or carbon
backbone material. The use of diepoxide monomers within a sol-gel matrix has
yet to be described as a means of obtaining high performance coating
materials. This paper describes the preparation and characterization of UV
curable inorganic-organic hybrid glass materials based on the incorporation
of cycloaliphatic diepoxide monomers into a sol-gel composition of TEOS and
the epoxide silane coupling agent glycidoxypropyl-trimethoxysilane. We
report aging and humidity studies along with processing conditions that
affect the silicate distribution and cationic cure of the diepoxide resin
based on solution and solid state NMR experiments. Mechanical analysis of
thin films prepared by varying processing conditions and length of the
diepoxide backbone are also discussed.
Modification of Sol-Gel Thin Films By Ion
Implantation
Authors: Hirashima Hiroshi , Adachi Kenji , Imai Hiroaki 
Published: April 2011

ABSTRACTIn order to densify and to improve the physical properties, TiO2
sol-gel films, about 100 nm in thickness, on silica glass or silicon wafer
were implanted with Ar+ or B+ ions. The refractive
index of the as-dried films increased and the IR absorption band of OH
disappeared after Ar+ implantation. Drying and densification of
sol-gel films were enhanced by Ar+ implantation. On the other
hand, the refractive index and the thickness of the films hardly changed
with B+ implantation. However, IR absorption bands of B-O bond
were observed after B+ implantation. This suggests that sol-gel
films could be chemically modified by ion implantation with reactive ion
species.
Hollow Mullite Ceramic Microspheres by Water Extraction of
Emulsified Aqueous Droplets
Authors: Liu Guoxu , Wilcox David L. 
Published: April 2011

ABSTRACTThis paper describes a novel colloidal route for the preparation of hollow
mullite ceramic microspheres with sizes in the range of 10 μm. An emulsion
technique was combined with a water extraction sol-gel process, to form an
aqueous droplet dispersion and gel the resulting droplets by extracting
water with a dehydrating liquid. The liquid-filled gelled microcapsules were
then dried and fired to form hollow ceramic microspheres. Important
processing variables controlling the microspherc morphology were determined
and a formation mechanism was proposed. Due to its potential applications in
microelectronic packaging, mullite was selected as the model material for
the present work, but the synthesis technique may be used for making other
single or multiphase ceramic compositions
Preparation of Transition Metal Oxides By A Nonhydrolytic
Sol-Gel Process
Authors: Arnal Pascal , Corriu Robert J.P. , Leclercq Dominique , Mutin P. Hubert , Vioux Andre 
Published: April 2011

ABSTRACTEtherolysis of metal chlorides offers a versatile, simple nonhydrolytic
sol-gel route to transition metal oxides. The main limitation of the process
results from the insolubility of some metal chlorides in non aqueous
solvents. The general tendency of this nonhydrolytic process is to delay
crystallization of metal oxides.
The Metal - Oxide Composite
[Fe0.2Co0.8]0.8[Fe2.38Co0.62O4]:
Hrtem and EDX Characterization
Authors: Noubeyo J. C Yamegni , Riera A. Malats I , Werckmann J. , Pourroy G. , Ehret G. , Poix P. 
Published: April 2011

ABSTRACTThe new metal-ferrite composite
[Fe0.2Co0.8]0.8[Fe2.38Co0.62O4]
is obtained by precipitation of ferrous and cobalt chloride in KOH. Further
heating under vacuum above 400°C shows a cationic exchange between metal and
spinel leading to a new composite made up of cobalt metal and cobalt doped
magnetite.HTERM and EDX observations have been carried out on both composites, i.e.,
before and after vacuum annealing, We show that cationic exchange occurs
mainly in crystals made up of spinel, CoO and amorphous nanoparticles.