bluuebunny/crossref_metadata_2025_split huggingface dataset:
Passivating Organic Coatings with Silicone Gels: The Correlation Between the Material Cure & its Electrical Reliability
Authors: Wong C. P. 
Published: March 2011

AbstractSilicone gels are becoming some of the most accepted protective coatings for VLSI integrated circuits due to their excellent electrical, thermal, and soft gel-like nature and properties, as well as their ultra-purity and ability to protect IC devices against severe environments. Recent studies indicate that proper IC Chip surface protection with high performance silicone gels in low-cost, non-hermetic plastic packaging might well replace the conventional hermetic ceramic packaging. This paper describes the use of the soft silicone gels and coatings in IC devices. It also describes the correlation between the material cure temperature and cure time versus their adhesion and electrical reliability during 85°C, 85% RH and bias accelerating testing.
The Processing and Properties of Multilayer Interconnection Structures Using Thermoset Films Derived from Bisbenzocyclobutene.
Authors: Townsend P. H. , Burdeaux D. C. , Hahn S. F. , Thomsen M. , Carr J. N. 
Published: March 2011

AbstractMultilayer interconnection structures incorporating a novel polymeric dielectric derived from a bis-benzocyclobutene(bis-BCB) monomer have been fabricated. This paper discusses the processing conditions for the construction of these circuits and describes electrical characteristics of the dielectric layers. The relative dielectric constant of the BCB film was 2.7. Thermal cycling produced no significant change in the conductance of three level metal via chains through two layers of the polymer.
Silicon Hybrid Multi-Chip Modules
Authors: Trigg Alastair D. 
Published: March 2011

AbstractThe Research Initiative on Silicon Hybrids (RISH), is one of several National Electronics Research Initiatives created under the auspices of the UK Department of Trade and Industry. Its aims are to investigate the merits of silicon hybrids, evaluate their performance and develop the technology necessary for their implementation. The paper describes the design and fabrication of silicon hybrids using thin film metal-polyimide interconnect. Several chip attach options are considered. The merits of the technology are illustrated using functional circuit demonstrators.
SiO2-TiO2-ZrO2 Gel Glasses - Reaction Kinetics and Properties
Authors: Beier W. , Frischat G. H. 
Published: March 2011

ABSTRACTSolutions have been prepared containing silicon ethoxide, titanium butoxide, and zirconium propoxide as metal organic compounds. Additions of water (for hydrolysis), solvents (ethanol, formamide), and hydrochloric acid (as a catalyst) have been varied systematically. The reaction kinetics of the hydrolysis and condensation steps in these mixtures have been studied by measuring viscosity and 29Si NMR data as a function of time. After gelling, the products have been dried and then converted to glassy materials by firing. Temperatures well below 1000 °C have been used for that. Glasses from the title system have been obtained both in bulk and in thin film form. Properties like density, specific surface, and hardness have been investigated and are reported as well.
Hafnium Metallo-Organic Films and Gels Produced by Sol-Gel Processing
Authors: Gagliardi Charles D. , Berglund Kris A. 
Published: March 2011

ABSTRACTMetallo-organic materials are often used as precursors for highly refractory oxides and hightemperature composites. The feasibility of producing hafnium metallo-organic films and gels by sol-gel techniques is demonstrated in the present study. Since hafnium alkoxides are not commercially available, their preparation is an obstacle in the development of their sol-gel processing applications. A common synthesis technique was used to produce hafnium isopropoxide, which was subsequently hydrolyzed under acid catalyzed conditions to produce films and gels. The films were prepared by spin casting and remained optically transparent. Initially, the gels were also optically transparent, but became translucent upon drying. Raman, IR, and light scattering spectroscopies were used to characterize this sol-gel process, and it is compared with the analogous processing of titanium and zirconium alkoxides.
Ceramic Processing using Inorganic Polymers
Authors: Lannumti John J. , Schilling Christopher H. , Aksay Ilhan A. 
Published: March 2011

ABSTRACTInorganic polymers are used in the formation of green compacts via sedimentation of colloidal alumina suspended in chloroform. Polymers containing highly polar components tend to produce constant density profiles of greater than 55% density, while those containing nonpolar, reactive components produce profiles with a large gradient in packing density. Density profiles describing the sedimentation behavior versus time and the final dried density of the compacts are generated via the use of gamma-ray densitometry. These polymers have the potential not only to increase green compact density but also to reduce weight losses due to “burnout” and subsequent sintering requirements by pyrolyzing to a ceramic phase.
Conversion of Alkoxide Solutions to Oxides: Evaporation of Products
Authors: Lipeles R. A. , Coleman D. J. 
Published: March 2011

ABSTRACTThe evaporation of organic by-products released during drying of 1-mm thick silicon tetramethoxide gels was analyzed using gas chromatography. The evaporation kinetics of methanol depended on the drying rate achieved by flowing dry air over the gel. For drying at flow rates less than 50 cm 3/min, exponential kinetics were observed initially with a long time constant (about 100- to 400-min). For drying rates greater than 70 cm3/min, diffusional (t−1/2) kinetics were observed initially. Cracking of the gel during drying was used to indicate the degree of stress. At low drying rates, minor cracking was observed near the edges of the gel. At high flow rates, extensive cracking was observed in samples that exhibited early t−1/2 kinetics. Monitoring the kinetics of drying is essential to optimizing the drying conditions to minimize stress and cracking in gels.
Processing of Crystalline Li(Nb, Ta)O3 Films with Preferred Orientation Through Metal Alkoxides
Authors: Hirano Shin-Ichi , Kato Kazumi 
Published: March 2011

ABSTRACTLiNbO3 and LiTaO3 are very attractive and useful materials, which have been applied to piezoelectric and electro-optic devices. The authors have synthesized the stoichiometric crystalline fine powders and films of LiNbO3 at temperatures as low as 250°C by the controlled hydrolysis of double alkoxide solutions; and this method was used to prepare Li(Nb, Ta)O3 solid solution films with and without the preferred orientation. Water used during the processing played an important role in the low-temperature crystallization and the elimination of free carbon in the films. The water for the partial hydrolysis affected the properties of alkoxide solutions for dip-coating, and the morphologies of crystalline films. Water in a mixed gas flow with oxygen during calcination accelerated the crystallization of the alkoxy-derived films at low temperatures.
Characterization and Processing of CVD Powders for Fabrication of Composite and Compound Ceramics
Authors: Hori Saburo , Shigaki Yoshiki , Hirata Yoshihiro , Yoshimura Masahiro , Sōmiya Shigeyuki 
Published: March 2011

ABSTRACTTwo-component oxide powders were prepared in the systems Al2O3-ZrO2. Al2O3-TiO2. and Al2O3-SiO2 by a CVD (chemical vapor deposition) technique using a combustion flame for the purpose of fabricating respective composite or compound ceramics. The CVD powders were spherical and ultrafine (av. 30–70 nm) with log-normal size distribution, and exhibited either very homogeneous or nanoheterogeneous structure and crystallographic metastability in phases and solid solutions. By starting from these CVD powders, not only uniform and excellent microstructure was achieved in the sintered products, but also better sinterability and novel microstructure became possible owing to the metastability which reflected the formation mechanism of two-component powders at high temperatures. CVD powders, which were previously considered difficult to sinter, proved to be excellent starting materials for fabrication of composite and compound ceramics when improved processing techniques were applied.
Zero-Shrinkage Whisker Fraction in Ceramic Matrix-Ceramic Whisker Composites
Authors: Holm Elizabeth A. , Cima M. J. 
Published: March 2011

ABSTRACTA Monte Carlo computer simulation that percolates soft-core, pseudographic whiskers in a discrete matrix has been developed, and two- and three-dimensional whisker percolation thresholds were determined for various whisker aspect ratios. The percolation thresholds were found to agree with the predictions of the excluded volume theory of percolation; moreover, the thresholds were found to coincide with the zero-shrinkage whisker fraction in ceramic matrix-ceramic particle composites.
Densification Behavior of Al2O3 Powders Containing ZrO2 Inclusions
Authors: Sudre O. , Lam D. C. C. , Lange F. F. 
Published: March 2011

ABSTRACTDensification experiments using ZrO2 single-crystal particles in an Al2O3 powder matrix were performed to examine the microstructural changes produced by constrained densification. Observations showed the formation of large, lowdensity regions within a denser material network. Enlargement of pores by desintering of necks between grains was observed during grain coarsening within these low-density regions. This pore opening behavior was also investigated in a model experiment.
Structural Problems and Non Stoichiometry in Thallium, Bismuth, and Lead Cuprates
Authors: Raveau B. , Michel C. , Hervieu M. , Groult D. , Provost J. 
Published: March 2011

ABSTRACTAn over view of the crystal chemistry of the layered bismuth, thallium and lead cuprates is presented here. The classification of these oxides is examined, and the problems of non stoichiometry, especially of extented defects and incommensurability of the structures, are discussed in connection with the superconducting properties of these materials. A particular attention is paid for the role of the lone pair cations in the structural properties of these oxides.
Single Cu-O Layer Bismuth Strontium Cuprates: Crystal Growth and Electronic Properties
Authors: Schneemeyer L. F. , Waszczak J. V. , Fleming R. M. , Martin S. , Fiory A. T. , Sunshine S. A. 
Published: March 2011

ABSTRACTThe growth of single crystals of Bi2+xSr2−yCuO6±δ from alkali chloride fluxes, typically sodium chloride is reported. Electronic properties of the resultant crystals are controlled by the melt composition and the partial pressure of oxygen during growth. Superconducting crystals with Tc's near 10K are obtained under low oxygen partial pressures from melts which are strontium-rich. Measurements of transport, tunneling and magnetoconductivity in nonsuperconducting crystals show two-dimensional localization within the CuO2 planes. Superconductivity occurs only when transport perpendicular to the planes gives rise to extended states in three dimensions.
Hrem on Grain Boundaries in Oxide Superconductors
Authors: Zandbergenl H.W. , Tendeloo G. van 
Published: March 2011

ABSTRACTHigh resolution electron microscopy has been carried out on grain boundaries in a number of superconducting oxides: YBa2Cu3O77−∂, LaCaBaCu3O7−∂, Bi2Sr2CanCun+1O2n+6+∂, and Pb2(Sr, Ca)3−xAxCu2+nO6+2n+∂. In general no amorphous material or another phase is observed at the grain boundaries. It is argued that the low critical currents in these polycrystalline materials are caused by the atomic structure of (001) interfaces at grain boundaries and concerning YBa2Cu3O7 and LaCaBaCu3O7−∂ by the intercalation of CuO layers starting from the grain boundaries.
Analysis of Superconducting Oxide by 7 MeV Alpha Particle Backscattering Analysis
Authors: Yonezawa Hiroki , Hidaka Yoshikazu , Suzuki Minoru , Shigematsu Toshio 
Published: March 2011

ABSTRACTHigh energy Ion backscattering analysis in combination with recently-developed resonance scattering analysis Is described, with a stress on precise and quantitative oxygen analysis and its successful application to the characterization and quality estimation of high Tc oxide superconductors. Particularly, the present status of high energy ion backscattering analysis, the review of analytical results for YBa2Cu3O7−x, the estimation of composition and crystalline quality of (La1−xSrx)2CuO4 by 7 MeV alpha particle backscattering analysis are described.
On the Origin of the Structural Modulation in the Bi Cuprates As Derived from 3d-Metal Substituted Phases
Authors: Tarascon J. M. , LePage Y. , McKinnon W. R. , Tselepis E. , Barboux P. , Bagley B.G. , Ramesh R. 
Published: March 2011

ABSTRACTA substitution for Cu by a 3d-metal (Fe, Co, Mn) in the superconducting Bi phases (Bi2Sr2Can−1CunOy; n = 1,2 and 3) has led to the discovery of new phases. These 3d-metal substituted phases are non-superconducting and, in contrast to the Cu-based phases, they exhibit a structural modulation that is commensurate. Single crystal x-ray studies were performed on the Bi2Sr3Fe2Oy, Bi2Sr2CoOy and Bi2Sr2MnOy compounds. A result, in common, is that the modulation is caused by the periodic insertion of a row of oxygen atoms in the Bi layers and this results in a corrugated-like slab structure. The Bi-O layers can be described as composed of alternating rocksalt-type and oxygen deficient perovskite-type blocks. For the Fe (n=2) phase the Bi atoms form ribbons (chains) in the ab plane. This is in contrast to the n=1 Co or Mn phases for which a disorder at the oxygen position is observed. Although the extra oxygen in the Bi-O layer could account for the doping mechanism in the high Tc Bi-phases, cation non-stoichiometry may also beimportant.
Identifying the Pairing Mechanism in High-Tc Superconductors
Authors: Goodenough J.B. , Manthiram A. , Zhou J. 
Published: March 2011

ABSTRACTIt is argued that the origin of the high transition temperatures observed in Ba1−xKxBiO3 and the copper-oxide superconductors with perovskite-related structures is due to two factors: (1) overlap of a partially filled σ* band of primarily cation character and a π or π* band of mostly O-2pπ parentage permits charge transfer between cation and anion subarrays with oxygen-atom displacement perpendicular to a M-O-M bond axis and (2) bondlength mismatch places the M-O-M bondlength under a compressive or tensile stress. Relief of a compressive stress by the bending of a M-O-M bond from 180° introduces a strong electron-lattice interaction with holes; a 180° Cu-O-Cu bond allows strong electronlattice coupling with electrons of a Cu2+/+ redox couple, but not with holes in a Cu3+/2+redox couple.
Comparison of the Hole Conductivities in Ceramic Cuprate Semiconductors and High-Tc Superconductors, as Reflected in the Difference between Oxygen and Copper Madelung Site Potentials
Authors: Metzger Robert K. , Torrance Jerry B. 
Published: March 2011

ABSTRACTThe Madelung energies of 18 cuprates and 1 nickelate with sheets or chains of Cu and O have been computed, along with the relevant Madelung site potentials for O and Cu. The difference between these site potentials has been shown to correlate extremely well with the conductivity of these cuprates: only if the site potential difference is intermediate can the holes (the presumed charge carriers) move more easily between Cu and O sites in the CuO2 sheets.
Composition of Superconducting La2CuO4+δ a Superconductor Doped by excess Oxygen Defects
Authors: Dabrowski B. , Hinks D. G. , Jorgensen J. D. , Richards D. R. 
Published: March 2011

ABSTRACTWe have studied mixed-phase samples of bulk LazCuO4 using neutron powder diffraction, thermogravimetric analysis and resistivity measurements. Samples fired at 950°C and slowly cooled form in the K2NiF4 structure with CuO impurities for z<2 and La2O3 impurities for z>2. Neither La-vacancies nor stacking defects were found. The bulk resistivity of the samples show semiconducting behavior which is shorted at 38K by small amounts of superconducting material. The superconductivity is due to the presence of an oxygen-rich phase with stoichiometry La2CuO4.08. The occurrence of superconductivity in pure La2CuO4.08 with the same Tc as observed in the doped La1.85 Sr0.15CuO4 indicates that the excess oxygen provides the same level of doping as metal-ion substitution.
Direct Observation of Intermixing in GAAS/AIAS Multilayers After Very Low-Dose Ion-Implantation
Authors: Bode M. , Ourmazd A. , Rentschler J.A. , Hong M. , Feldman L.C. , Mannaerts J.P. 
Published: March 2011

ABSTRACTWe combine chemical lattice imaging and digital vector pattern recognition to study quantitatively, kinetic intermixing in GaAs/AlAs multilayers. We thus obtain, with atomic plane resolution and near-atomic sensitivity, composition profiles across each interface of a multilayer stack before and after ion-implantation. Our results show significant intermixing even when only one 320 keV Ga+ ion is implanted at 77 K into each 2000 A2 area of the interface. This corresponds to an incident ion dose of 5×l012/cm2.The intermixing is not uniform along the interface. At each interface, we observe more intensely intermixed regions, whose widths correspond to those created by the damage track of a single implanted ion, as expected from Monte-Carlo simulations. It thus appears that we can directly image intermixing due to single energetic ions implanted into the multilayered GaAs/AlAs structure.
Effect of Carbon on Ion Beam Mixing of Fe-Ti Bilayers
Authors: Hirvonen J-P. , Nastasi M. , Lappalainen R. , Sickafus K. 
Published: March 2011

ABSTRACTThe influence of implanted carbon on ion beam mixing of a Fe-Ti system was investigated. Carbon was introduced into bilayer samples by implanting 13C isotopes. The implantation energies were selected to set the mean range of carbon ions in either the iron or titanium layer. The effect of implanted carbon on 400 keV Ar ion mixing in the temperature range from 0 to 300 °C was studied using Rutherford backscattering spectroscopy at the energy of 5 MeV. Changes in carbon concentration profiles were probed utilizing the resonance of the nuclear reaction l3C(p,y)14N at the proton energy of 1.748 MeV. The measurements revealed that mixing was not affected by carbon implanted into the titanium layer. However, carbon in the iron layer remarkably retarded mixing at all temperatures investigated. Significant changes in carbon depth distributions were observed only when the sample with implanted carbon in the iron layer was mixed at 300 °C. These result are explained in terms of the enhanced mobility of carbon in an evaporated iron film which allows segregation to the interface. At low temperatures, however, vacancy-carbon interaction in iron may have a contribution to the retarded ion beam mixing.
Ion-Beam Mixing and Tribology of Fe/B Multilayers
Authors: Hu Renyuan , Rehn L. E. , Fenske G. R. , Baldo P. M. 
Published: March 2011

ABSTRACTInterdiffusion of Fe and B trilayer specimens during 1-MeV Kr+ bombardment was studied using Rutherford backscattering and electron microscopy. The square of the interdiffusion distance during mixing at 300°C was found to depend linearly on the irradiation dose. Arrhenius behavior with an apparent activation enthalpy of 0.7 eV was observed for the mixing between 200 and 500°C. Electron microscopy of ion-beam mixed multilayer specimens revealed that two crystalline compounds, Fe2B and Fe3B, formed during bombardment at 450°C, while two different amorphous Fe/B phases formed at 300°C. Substantially improved adhesion and reduced friction were observed for Fe/B multilayers ion-beam mixed onto M50 steel substrates at 450°C.
Molecular Dynamics Simulations of the Interactions of Excited Electrons
Authors: Mazzone A. M. 
Published: March 2011

ABSTRACTIn this work the processes of electron-electron interaction taking place in a highly excited electron gas are analyzed on the basis of molecular dynamics simulations. The time evolution of the system is described by using either classic mechanics or a quantum mechanical representation. New aspects of the collective behaviour of the particles are born out by the simulations.
Molecular Dynamics Simulations of Ionized Cluster Beam Deposition
Authors: Hsieh Horngming , Averback R.S. , Benedek R. 
Published: March 2011

ABSTRACTFully dynamical computer simulations have been used to study the physical mechanisms of ionized cluster beam deposition. Clusters containing 92 atoms were directed at <001> surfaces with energies per cluster atom ranging from one sixth to three times the cohesive energy of the target. Simulation events employed either Lennard-Jones or Embedded Atom Method potentials. The atoms in the cluster appear to undergo local melting on impact with the substrate. Higher cluster energy increases the spreading of cluster atoms on the substrate and improves epitaxy, but it also increases interdiffusion and produces point defects.
Analysis of Scanning Tunneling Microscope Topographs of Graphite Surfaces Roughened by Ar+ Ion Bombardment
Authors: Eklund Elliott A. , Williams R. Stanley , Snyder Eric J. 
Published: March 2011

ABSTRACTThe scanning tunneling microscope (STM) has been used to investigate graphite surfaces roughened by 5 keV Ar+ ion bombardment. The (0001) surfaces of several samples were etched with the same total ion dose but with different sputter rates for each surface. STM images taken after sputtering show that the roughness of the sputtered surfaces depended on the sputter rate and that the surface topography of each sample appeared self-similar over a large range of length scales. These experimental observations agree with predictions of the recently proposed Shadow Model. The two dimensional height-height correlation function is utilized as a means of quantitative analysis for STM topographs of sputtered surfaces.
Electron Beam Induced Nanometre Hole Formation and Surface Modification in Al, Si And MgO
Authors: Bullough Tim J. , Humphreys C. J. , Devenish R. W. 
Published: March 2011

ABSTRACTA wide variety of materials which are normally undamaged when exposed to a lOOkeV electron beam in a conventional transmission electron microscope can be modified on a nanometre scale by the high current density electron probe in a dedicated scanning transmission electron microscope (STEM). A stationary 100keV STEM electron probe can produce holes typically l-5nm diameter through crystalline Al, Si and MgO tens of nanometres in thickness, while a scanned electron beam can smooth surfaces on an atomic scale.In Al the stationary electron probe in the STEM produces a row of facetted voids along the irradiated volume. The voids grow initially inwards from the electron exit surface, with each void typically 4nm in diameter and 12-24nm in length, separated by equal distances from one another. In contrast, continuous holes 1.2-1.6nm diameter form at the electron exit surface of Si when exposed to the focused electron beam. However, these holes form only at specific randomly distributed points separated from one another by 2-4nm over the surface of crystalline specimens of both n- and p-doped <001> and <111> Si.Square cross-section holes with widths of about lnm can be formed by the stationary electron probe in MgO crystals. Rastering the probe over a restricted area of MgO initially results in the rapid development of surface islands and channels which are subsequently removed to leave an atomically smooth surface.