bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reactions of Atomic and Molecular Fluorine on Silicon Surfaces
Authors: Stinespring C. D. , Freedman A. , Wormhoudt J. C. , Kolb C. E. 
Published: March 2011

AbstractThe reactions of atomic and molecular fluorine on silicon surfaces have been studied using x-ray photoelectron spectroscopy (XPS) and an ultrahigh vacuum (UHV) compatible microwave discharge effusive beam source of reactive species. The results indicate that molecular fluorine is dissociatively chemisorbed to form SiF2-like species on the surface. This reaction saturates at approximately monolayer surface coverage. Atomic fluorine also reacts initially to form SiF2-like surface species. Once the available surface sites are occupied, however, the fluorine atoms penetrate and react with silicon in the underlying layers. As the fluorine uptake increases, many of the subsurface silicon atoms become fully fluorinated. That is, the reaction product becomes SiF4-like. In contrast, preliminary studies indicate little difference in the behavior of atomic and molecular chlorine. These findings are compared with previous results for XeF2 adsorption, and their implications for plasma etching mechanism definition are discussed.
Indentation Load Relaxation Studies of Thin Film-Substrate Systems
Authors: Stone D. , Lafontaine W. , Ruoff S. , Hannula S.-P. , Yost B. , Li Che-Yu 
Published: March 2011

AbstractResults from indentation load relaxation (ILR) tests on thin film-substrate systems are reported. In the case of a 1 pum aluminum film on silicon, the data can be interpreted as reflecting both the properties of the film and the interface between film and substrate. Data from a 37μm TiN film on 304 SS are believed to reflect the combined behavior of the film and substrate.
Device Failures in Pressure Cooker Tests at 130°C
Authors: Burgess J. F. , Yerman A. J. 
Published: March 2011

AbstractThe results obtained from Moisture-Temperature-Bias testing of Power- MOSFET at 130°C and 85%RH are examined. A variety of packaging techniques were tested varying from plastic encapsulation materials/methods to fully hermetic. Unprotected devices were tested as controls. The predominant failure mechanism observed was aluminum corrosion, which was manifested initially as a leakage current increase and eventually as visually observable dissolution of aluminum and eventual open circuits.This paper examines the critical part that surface contamination plays in the corrosion process, particularly where condensed water films can form at the metal surface. The effectiveness of various plastic coating methods are viewed in the light of this concept. Aluminum lead bonds were more susceptable to corrosion than expected. A number of materials were identified that showed resistance to pressure cooker conditions.
Non-Conventional Route to Glass-Ceramics for Electronic Packaging
Authors: Gensse C. , Chowdhry U. 
Published: March 2011

AbstractThis paper describes a non-conventional route to formation of dense glass-ceramics at relatively low temperatures. Organometallic precursors were used to synthesize powders with controlled purity and stoichiometry in the MgO/A12O3/SiO2 system. These amorphous powders sintered by viscous flow to form a dense glass below 1000°C. Further heating resulted in the formation of very fine grained glass-ceramics. Beta-quartz, cordierite, and cordierite-mullite glass-ceramics were obtained with attractive properties for electronic packaging.
Characterization of Sol-Gel Derived Tantalum Oxide Films
Authors: Silverman L. A. , Teowee G. , Uhlmann D. R. 
Published: March 2011

AbstractWe have studied the densification and dielectric properties of sol-gel derived tantalum oxide thin films as the insulators in MIS capacitors. Hydrolysis of tantalum ethoxide is extremely rapid and goes to completion in ethanol. Condensation is also rapid, and goes to completion in toluene Multiple layers were applied by spin-coating up to thicknesses of 3000 Å before cracking of the coating during drying ensued. Densification occurs from room temperature to 450 C, with the original film thickness decreasing by about half in one hour at 450 C. No additional densification occurs upon heating to 750 C. The dielectric constant decreases from unfired samples to those fired at 450 C, and then increases on firing from 600 to 750 C. The value of the dielectric constant at 1 MHz for samples fired at 750 C for one hour is 20, similar to that of anodically grown Ta2O5. Leakage currents as low as 2 × 10−7 amp cm−2 have been measured for applied fields of 200,000 V cm−1.
Glass Films and Interfaces in Microelectronic Applications
Authors: Buchanan R. C. , Beck C. V. 
Published: March 2011

AbstractUse of dielectric films is integral to most microelectronic packaging, as passive components for device insulation (interlayer dielectric, passivation, diffusion layer), as thin layer capacitive structures or as insulating coatings for thin film and thick film hybrid circuits. Depending on deposition technique, film composition may include SiO2, Al2O3, Si3N4, modified silicate or phosphate glasses as insulators. Compositions as well as methodologies for film preparation on Si, glass or metal substrate by spin coating (or spraying) are discussed, including film/substrate interface characteristics and properties related to dielectric film coatings.
Metallo-Organic Decomposition (MOD) Films for Electronic Packaging
Authors: Vest Geraldine M. , Cone V. P. , Herzfeld C. J. , Bhansali A. K. 
Published: March 2011

AbstractA metallo-organic decomposition (MOD) film is one formed by thermal decomposition of a solution containing one or more metallo-organic compounds that were deposited onto a substrate. This process yields metal, glasses, or polycrystalline ceramic films directly without passing through the powder stage. Conductor films studied include a screen printable gold and a screen printable and ink jet printable silver. Dielectric films studied include a low K lead borosilicate glass and a variety of ferroelectric compositions.
Characterization of Surface Modified Carbon Fibers and Their Epoxy Composites by Small Angle X-Ray Scattering
Authors: Stoll Bernhard , Fellers J. F. , Lin J. S. 
Published: March 2011

AbstractThis paper correlates the interlaminar shear strength of 7 different carbon fiber/epoxy composite with structural characteristics determined by Small Angle X-ray Scattering (SAXS) measurements. The carbon fibers were all of the same type but had different surface treatments. The SAXS patterns of the fibers and of the composites showed a highly nonlinear Guinier region which could not be approximated by traditional linear regression. A new approach to the Guinier approximation was developed to treat this nonlinear curve using a polynomial of second order. The radius of gyration (RG) of the fibers, as determined by this new method, correlated clearly with both the extent of the surface treatment and the interlaminar shear strength of the composite. Also the difference in scattering between a dry fiber and a glycerine soaked fiber provides a way to characterize the changes obtained by surface treatments. These methods provide new ways to estimate the efficiency of a surface treatment and its effect on the interlaminar shear strength by analyzing the SAXS patterns of the fibers.
First Cumulant for Chains with Constraints
Authors: Akcasu A. Z , Hammouda B , Stockmayer W. H , Tanaka G. 
Published: March 2011

AbstractThe Fixman-Kovac formulation of chain dynamics with constraints is used to calculate the first cumulant Q(q) of the dynamic scattering function. This general formalism is applied to the case of freely jointed chains. It is shown that the large q limit (q being the scattering wavenumber) of Q(q) for a chain of N bonds in the absence of hydrodynamic interaction is proportional to the ratio (2N+3)/3(N+l) representing the fraction of unconstrained degrees of freedom of the chain. The inclusion of hydrodynamic interaction seems to enhance the apparent segmental diffusion. The use of constrained chain dynamics has no appreciable effects, however, on the behavior of Q(q) in the small and intermediate q regions for long enough chains. This formalism can be used to interpret neutron (spin echo) scattering experiments from semiflexible polymers in solution.
Scattering Studies on Mixtures of Poly(Ethylene Oxide) with Poly(Methyl Methacrylate)
Authors: Russell T. P. , Ito H. , Wignall G. D. 
Published: March 2011

AbstractMolten and semi-crystalline mixtures of PEO and PMMA have been investigated by small angle neutron and X-ray scattering. It has been found that the Flory Huggins interaction parameter, evaluated from the intermolecular scattering function, is quite small and is apparently dominated by entropic contributions. Scattering profiles from the semi-crystalline mixtures clearly show that the PMMA is incorporated within the amorphous phase between the crystalline PEO lamellae.
A Molecular Orbital Model of Melting and Glass Formation
Authors: Eberhart M. E. , Johnnson K. H. , O'Handley R. C. 
Published: March 2011

ABSTRACTSCF-Xα-SW calculations have been performed on the glass forming crystal of Ni2B. The resulting molecular orbital topology near the fermi level is similar to that previously obtained by SCF-Xα-SW calculation on the glass forming crystals of Pd-Si and Cu-Zr. These similarties, it is conjectured, indicate melting is an electronically driven phase transition and that liquid and glass structures are more the result of electronic than kinetic factors. It is shown that the molecular orbital model of melting in transition metals will generate structures similar to those resulting from the dense random packing of hard spheres method, and the molecualr orbital mechanism admits, in a qualitative way, the explanation of a broad range of liquid and glass properties.
Rapid Solidification of Metastable Materials
Authors: Liebermann Howard , Walter John 
Published: March 2011

ABSTRACTThere are numerous processing methods available for the fabrication of rapidly-solidified metastable alloys. Examples include splat quenching, melt-spinning, surface melting and quenching, melt atomization and solidification, and deposition by sputtering and evaporation. Experimental aspects of each of these fabrication methods will be discussed. These include solidification and quench rate, process control, and final product morphology and microstructure. Some properties of an amorphous alloy prepared by several of these processing methods will be discussed.
Electronic Structure of CuZr and PdSi Metallic Glasses
Authors: Leon Francisco A. , Johnson Keith H. 
Published: March 2011

ABSTRACTThe local electronic structures of representative amorphous alloys have been calculated using the SCF-Xα-SW cluster molecular orbital method. Prototype cluster models have been constructed for Cu-Zr and Pd-Si alloys which exemplify two major classes of binary (A-B) glass-forming systems, namely: (1) metallic glasses based on noble or transition elements (e.g., A=Cu) toward the right of the periodic table and transition elements (e.g., B=Zr) toward the left of the periodic table; (2) metalloid glasses based on transition elements (e.g., A=Pd) toward the middle of the periodic table and nonmetallic elements (e.g., B=Si) toward the right of the periodic table. The calculated electronic structures are in good quantitative agreement with, and provide an interpretation of, published photoelectron spectra for the above amorphous alloys.
The Effects of Ribbon Thickness and Annealing Temperature on the AC Magnetic Properties of the Fe81.5B14.5Si3C1 Alloy
Authors: Ihiuangp S.C. , Frischmann G. , Luborsky F.E. , Livingston J.D. , Mogro-Campero A. 
Published: March 2011

ABSTRACTThe a.c. magnetic properties measured at 60 Hz are found to be strongly affected by ribbon thickness and annealing temperature. These magnetic results are further characterized by observations on magnetic domain structure, crystallization, stress relaxation, and ribbon surface finish.
Influence Of Cr, Mn, Co and Ni on the Crystallization Behaviour of (Fel−xMx)y Metalloid1−y Metallic Glasses
Authors: Bergmann H. W. , Brokmeier U. 
Published: March 2011

ABSTRACTThe influence of Cr, Mn, Co and Ni on the thermodynamic properties (molar heat of fusion, heat of crystallization and melting temperature), crystallization behaviour and hardness was studied in (Fe1-xMx)83B17 as a function of the x content. The crystallization behaviour can be described by three parameters which enables an extrapolation to longer times.
Localized Shear Deformation of Amorphous Metals
Authors: Li J.C.M. 
Published: March 2011

ABSTRACTThe characteristics of localized deformation in amorphous metals are reviewed. All the available evidences seem to suggest that dislocations are responsible for shear localization. These dislocations seem to require a stress concentration for their nucleation. Once nucleated, they are capable of producing both forward and reverse shear in a narrow band, much like the dislocations in crystalline materials.
The Effect of Hydrogen on an Iron Based Amorphous Alloy
Authors: Shahani H. , Soderhjelm H. , Nygren Mats 
Published: March 2011

ABSTRACTIn this· investigation we have systematically studied the brittleness and the atomic structure in an Fe(SiBC) alloy. Different amounts of hydrogen have been dissolved in the alloy. It has then been studied at different cooling rates.Hydrogen gas of different partial pressures was dissolved into the melt. The alloy was then rapidly quenched by a chill block melt spinning method. The cooling rates were changed by changing the velocity on the chilling roll. The brittleness and the atomic structure were examined by bending tests and x-ray diffraction.X-ray diffractions showed that the ribbons were amorphous when the cooling rate was sufficient. Amorphous ribbons without any hydrogen were ductile, crystalline ribbons of this alloy were brittle. The ribbons with dissolved hydrogen and amorphous structure were brittle even at small amounts of hydrogen. At the highest cooling rates the ribbons with low hydrogen content were ductile. There seems to be a connection between the hydrogen content and the amorphous ribbons ductility. The hydrogen content only has a slight influence to amorphous structure.
Preferred Orientation in Splat-Quenched Materials
Authors: Blake N.W. , Rames F.A. , Smith R.W. 
Published: March 2011

ABSTRACTHigh purity, splat-quenched metal ribbons, produced by the melt spinning technique, were examined for preferred orientation using x-ray diffraction. Of the materials tested (Zn, Cd, Ag, Bi, Pb, Sb, Mg, Sn) all except Sn exhibited some degree of preferred orientation in the plane of the metal ribbon. the hcp metals Zn and Cd showed an extreme degree of preferred orientation with the 002 plane being closely parallel to the ribbon plane. The Zn ribbon was analysed more closely with a view to its use as a crystal monochromator for x-ray diffraction. The high purity Zn was found to have some instability of preferred orientation with increase in time and temperature. The orientation was found to be effectively stabilized by the intentional addition of impurities, or by the use of lower purity (99.99%) Zn. In this form, the Zn ribbon could be used as a crystal analyser for x-ray diffraction with both intensity and resolution comparable to that of the 1011 plane in Quartz.
Pseudo-Elastic Behaviour in Rapidly-Quenched Dilute Tin Alloys
Authors: Callernfault W.M. , Smith R.W. 
Published: March 2011

ABSTRACTRibbons of pure tin (99.9999%) and dilute Sn-Ge alloys, prepared by melt spinning using a 4′ diameter copper cylinder, were strained in tension. Reversible strains of a few percent were recorded in the dilute alloys but not in the pure tin. X-ray diffraction examination suggests that this pseudoelasticity is due to twinning rather than a martensitic transformation.
Surface Melting of Cast Iron With a High Power Laser Beam
Authors: Nilsson Ylva 
Published: March 2011

ABSTRACTAn investigation is done on partial surface hardening and alloying on cast iron by means of a high power laser beam. Samples of cast iron have been covered with alloying material i.e. Ti, Cr, Si, V and Nb respectively. The samples were irradiated with a 2.5 kW laser beam. A partial melting of the surface occured and the alloys were dissolved. The carbide structure in the resolidified part was governed by the alloy addition. The carbide structure was metallographicly analysed. The effect of different parameters as beam diameter, scanning rate, power and alloy content have been investigated and the crack frequency has been evaluated.
Transmission Electron Microscopy of RSP Fe/Cr/Mn/Mo/C Alloy
Authors: Rayment J. J. , Thomas G. 
Published: March 2011

ABSTRACTRapid solidification processing (RSP) has been carried out on an Fe/Cr/Mn/Mo/C alloy using both electron-beam melting and piston-and-anvil techniques. Preliminary TEM results show RSP produces a refined duplex microstructure of ferrite and martensite, with a typical ferrite grain size of 0.50–3.0 microns. This RSP microstructure is significantly different from that observed in the conventionally austenitized and quenched alloys—a lath martensitic microstructure with thin films of retained interlath austenite. The morphological change produced by RSP is accompanied by an increase in hardness from 48Rc to 61Rc (^ 480 to 720 VHN). It is intended to use electron-beam specimens to examine the potential beneficial effect of RSP upon sliding wear resistance and, by careful TEM studies, it will be possible to characterize the microstructure and its role in the hardness and wear behavior of the RSP alloy.
Grazing Incidence X-ray Scattering Study of Defect Structures in MBE GaAs/Si Using Synchrotron Radiation
Authors: Laderman S. S. , Kortright J. , Scott M. , Fischer-Colbrie A. 
Published: March 2011

ABSTRACTDefect structures in thin, MBE grown, GaAs/Si(001) heteroepitaxial films were studied with grazing incidence x-ray scattering techniques. The diffuse scattering associated with GaAs having the predominant epitaxial orientation varied strongly with the penetration depth of the x-rays. Well directed streaks corresponding to planar faults were observed and easily distinguished from a broad and more randomly oriented background. Bragg peaks corresponding to twinned GaAs were also studied. The probability of twinning was seen to be much higher about the {111} planes whose normals, when projected onto the sample surface, lay parallel to the off-orientation direction than about the {111} planes whose normals, when projected onto the sample surface, lay perpendicular to the off-orientation direction. The intensity and breadth of the twin reflections were analyzed to estimate the corresponding defect density. The depth dependence of the twinning probability was seen to vary with growth parameters.
Characterization of GaAs and Ge Films on (100) Silicon
Authors: Baribeau J.-M. , Houghton D.C. , MaignÉ P. , Moore W.T. , Devine R.L.S. , Denhoff M.W. , Stoner R.J. , Mccaffrey J. , Jackman T.E. 
Published: March 2011

ABSTRACTA UHV MBE apparatus in which the deposition of both group IV and group III-V components is possible without breaking vacuum has been utilized to compare the growth of GaAs epilayers on non-polar Si(100) and Ge coated Si(100) substrates. In addition, a comparison of GaAs epilayers grown on substrates cleaned by ex-situ techniques and on substrates given all UHV in-situ surface preparation was made. Defect reduction by the incorporation of strained-layer superlattice dislocation filters and by post-growth rapid thermal anneal (RTA) thermal cycles was also investigated. Optical and material properties comparable to MBE grown GaAs/GaAs were obtained for GaAs grown on Ge coated Si(100) substrates.
Comparative Studies of the Structural, Electrical and Opto-Electronic Properties of Epitaxial GaAs Layers Grown On Either Si, Ge Or Ge Coated Si Substrates By Mocvd
Authors: Abdul Awai M. , Lee El Hang , Chan Eric Y. , Lum R.M. , Klingert J.K. , Sheng T.T. , Hopkins L.C. , Opila R.L. 
Published: March 2011

ABSTRACTWe report the epitaxial growth of GaAs films on bulk Si, Ge and Ge coated Si substrates by MOCVD. This work is directed at comparing the structural, electrical, optical and optoelectronic properties of the GaAs films grown on these substrates. The quality of the GaAs films was evaluated by a number of techniques including X-ray, TEM, RBS, I-V and C-V. We have also obtained good photoresponse for Au-GaAs/Si, Au-GaAs/Ge and Au-GaAs/Ge/Si Schottky diodes at 0.87μm. We have observed significant differences in defect density, strain, crystalline quality, structural order, doping density depth-profile, dark current, diode ideality factor, photoresponse, inter-diffusion and interface structure among these three different structures. The GaAs/Ge structure exhibited the best structural and electrical characteristics of all. The GaAs/Ge/Si structure showed material properties and Schottky diode performance that are better than those of the GaAs/Si stucture. Although Ge and Si both out-diffuse into GaAs, that the out-diffusion of Si into GaAs appears to cause more degradation in the electrical and optoelectronic properties of GaAs.
Strain Measurements in Si/Si0.5Ge0.5 Superlattices by He Ion Channeling
Authors: Mantl S. , Kasper E. , Jorke H. J. 
Published: March 2011

ABSTRACTHe ion channeling experiments have been performed on molecular beam grown Si/SiGe superlattices to determine the strain fields. Angular yield scans provide directly the tetragonal strains in the layers. In Si/Si0.5Ge0.5 superlattices grown on (100) Si only the SiGe layers are strained. Almost equal but opposite strains in the Si and SiGe layers have been found in a Si/Si0.5Ge0.5 superlattice deposited on a 230 nm thick SiO.71Ge0.29 buffer layer. Strain symmetrization yields the minimum elastic energy and thus to the most stable structure.
Epitaxial Ge Films on Si Substrates
Authors: Mccalmont J.S. , Robinson D. , Lakin K.M. , Shanks H.R. 
Published: March 2011

ABSTRACTThin films of germanium have been prepared using an ultrahigh vacuum ionized-cluster beam (ICB) system. The dopant concentration of the films was varied by alloying the germanium source material with aluminum, a p-type dopant. X-ray diffraction analysis of the films has shown that an epitaxial (100) germanium film can be deposited on a (100) silicon substrate with a substrate temperature as low as 300°C. The results confirm that ICM deposition can be used to prepare epitaxial germanium films, but ionization of the clusters does not appear to affect the film growth.
Electrical Transport in Ultrathin Films of CoSi2 on Si(111)
Authors: Hensel J. C. , Phillips J. M. , Batstone J. L. , Augustyniak W. M. , Unterwald F. C. 
Published: March 2011

ABSTRACTWe have performed electrical transport measurements on ultrathin films of epitaxial CoSi2 on Si(111) with film thickness ranging down to ∼10A. The resistivities exhibit temperature dependences characteristic of a metal and a thickness dependence which rises steeply with decreasing thickness suggestive of a quantum size effect. At the lowest temperatures (≲ 10K) the resistivities of the thinner films increase logarithmically with inverse temperature characteristic of transport in the weak localization regime as has been confirmed by magnetoresistance measurements. Hall effect measurements establish that carrier densities (holes) in the ultrathin films are essentially identical to those in bulk CoSi2, i.e. 26 × 1022 cm−3.