bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sub-Boundary Formation and Suppression in Silicon films Recrystallized by Scanned Zone Melting
Authors: Pfeiffer Loren , Gibson J. M. , Kovacs T. 
Published: March 2011

ABSTRACTWe observe that the formation of low angle grain boundaries (sub-boundaries) depends strongly on the thickness of the recrystallized Si film. The average lateral spacing between adjacent sub-boundaries increases from 40 μm for 4000Å films to 500 μm for unseeded Si films 30 μm thick. For seeded 30 μm Si films on 1.6 mm by 1.6 mm buried oxide islands, areas exceeding 1.0 mm by 1.0 mm have been recrystallized which are free of all sub-boundaries, but which contain dislocations in other configurations.
An Auger Electron Spectroscopy (AES) Investigation into the Effect Annealing on the Phase Distribution of Ion Implanted Oxygen in Silicon
Authors: Tuppen C G , Davies G J , Taylor M R , Heckingbottom R 
Published: March 2011

ABSTRACTBuried oxide layers, formed by high dose ion implantation, have been examined using Auger depth profiling. The phase distribution of oxygen in the wings of the implant profile and effects of high temperature annealing, have been investigated. Ion beam induced cascade mixing, which occurs during sputter etching, limits the minimum detectable size of SiO2 precipitates. However, it is possible to minimise this effect by reducing the ion beam energy. At very small precipitate sizes (<100Å) silicon atoms at the edge of the precipitate particles will make a major contribution to the Si KLL Auger spectrum. A previously reported theoretical model has been expanded to take account of this phenomenon.
X-ray Microanalysis and High Resolution Imaging of Ge-Au-Ni Metal Layers on Gallium Arsenide
Authors: Fathy D. , Krivanek O. L. , Spence J. C. H. , Paulson W. M. 
Published: March 2011

ABSTRACTOhmic contacts to GaAs have been studied using a high resolution TEM, an SEM and a STEM with an energy dispersive x-ray attachment. Two different deposition sequences of the constituent Au-Ge-Ni metals yielded specific contact resistivities that varied by one order of magnitude. Crosssection images of the interface between the GaAs and the metal Au-Ge-Ni layers following alloying showed protrusions at the interface. Contacts with low specific resistivities showed deeper protrusion and also significantly more Ge and Ni in the GaAs.
Low Temperature (150–250°C) Deposition of n+ and p+ Microcrystalline Silicon for VLSI Device Contacts
Authors: Rajeswaran G. , Vanier P. E. , Kampas F. J. , Corderman R. R. 
Published: March 2011

ABSTRACTThe rf glow discharge decomposition of dilute mixtures (∼1%) of SiH4 in H2, with suitable doping agents such as PH3 or B2 H6 added, produces n+ and p+ microcrystalline (μc) silicon films with resistivities (ρ) in the 10−1 Ω.cm range at exceedingly low substrate temperatures Ts (150–250°C). The μc-Si films consist of two phases with crystalline clusters embedded in an amorphous matrix. The films are stable when temperature-cycled in the 30–400°C range and the resistivity decreases when annealed above the original deposition temperature. A model of microcrystalline film growth involving the reactions between the gas phase radicals and the growing film surface is proposed.
Analysis of Implanted Boron Profiles Across the Si-SiO2 Interface by Secondary Ion Mass Spectrometry.
Authors: Deline V. R. , Johnson N. M. , Christel L. A. 
Published: March 2011

ABSTRACTDepth profiles of boron implanted across the SiO2-Si interface have been measured by secondary ion mass spectrometry and compared with model calculations of the impurity distributions. Analysis of the sputtering and ion yield processes near the interface are used to reconstruct the measured boron profile for comparison with the model calculations. Applicability of the method of profile reconstruction near the interface to other materials and impurities is discussed.
Quantitation of Secondary Ion Mass Spectrometry (SIMS) for HgCdTe.
Authors: Lapides Lawrence E. , Whiteman George L. , Wilson Robert G. 
Published: March 2011

ABSTRACTQuantitative depth profiles of impurities in LPE layers of HgCdTe have been determined using relative sensitivity factors calculated from ion implantation profiles. Standards were provided for Li, Be, B, C, F, Na, Mg, Al, Si, P, S, Cl, Cu, Ga, As, Br, and In. Relative sensitivity factors as a function of ionization potential for O2+ primary ion SIMS and electron affinity for Cs+ primary ion SIMS have been calculated in order to extend quantitation to elements not yet implanted. Examples of depth profiles for implant standards and unimplanted layers are given.
A Comparison of Thermal, Line-Source Electron Beam and CW Laser Annealing for the Fabrication of Ersi2 Schottky Barrier on Si.
Authors: Wu C. S. , Scott D.M. , lau S. S , Wakita A. , Sigmon T. W. , Knapp J. A. , Picraux S. T. 
Published: March 2011

ABSTRACTErSi2 contacts formed by reacting Er with single crystal silicon using conventional furnace heat treatment are dominated by pits. Recently rapid electron and laser beam heating have been used to form pit-free ErSi 2 layers on Si by reacting Er with the Si substrate. For this investigation we studied the electrical properties of erbium silicide/Si<p,100> contact prepared by thermal, laser and electron beam annealing. We prepared and annealed three types of samples; (I) Er(600Å)/Si<p,100>, (II) Si(100Å)/ Er(600Å)/Si<p,100> and (III) Si(900Å)/Er(600Å)/Si<p,100>.The barrier height of the pit-free thermal annealed samples (type III) was ∼0.78 eV. All laser and e-beam annealed samples were observed to be pit-free. The barrier heights for the laser annealed samples varied from ∼ 0.63 eV for type I samples to ∼ 0.77 eV for type III samples. The e-beam annealed samples gave barrier heights ∼ 0.71 eV (type I and II) and ∼ 0.77 eV for type III. The barrier heights of beam processed diodes shifted towards the 0.78 eV range upon post-annealing. We model these results in terms of defects created at the ErSi2-Si interface.
Manufacture of Penetrating-Pores Metals by High Gas Pressure
Authors: Okumoto Yoshihiro , Takata A. , Ishizaki K. 
Published: March 2011

ABSTRACTOpen porous metals can be made by direct hot isostatic press (HIP) treatment on a cold isostatic pressed body. In this work, porous metals with uniaxially penetrating pores were produced using a modified HIP method.Penetrating pores from one surface to the other surface are useful for filter applications, and were produced by forcing pressurized gas to travel through samples by alternating the HiPping pressure during sintering.In this experiment, copper powder was used. Samples produced with this new method have higher permeability coefficient than those produced by the normal HIP method.
Fiber Dispersed Porous Alumina Sintered under Direct High Gas Pressure for High Thermal Shock Resistant Application
Authors: Kurushima Toyokazu , Ishizaki K. , Osaki S. 
Published: March 2011

ABSTRACTFiber dispersed porous alumina ceramics were produced by a direct high gas pressure sintering method. The produced materials exhibited relative densities of 75–85%, high bending strength and good thermal shock resistance. The alumina ceramics were characterized by lower closed porosity and higher open porosity. These characters strengthen the thermal shock resistance of porous ceramics. This high gas pressure sintering by the direct high gas pressure sintering method densifies only bridge parts of alumina ceramics which support pores. This process is concluded to be effective to produce materials with higher strength, better thermal shock resistance and higher open porosity.
HIP of Powder Mixtures
Authors: Funkenbusch P.D. , Li E.K.H. 
Published: March 2011

ABSTRACTModels of pressure-sintering and consolidation (such as that found in the HIP process) often assume a uniform spherical powder. However, it is known that use of mixtures, containing particles of differing composition and/or size, alters the initial powder packing and subseguent HIPing behavior. We have experimentally investigated these effects using the simplest form of mixture; a bi-modal powder with various size ratios and particle fractions. Packing experiments confirm the existence of “optimum” packing fractions for which the density is maximized over both monosized and the as-received (continuously distributed) powders. During HIPing these powder mixes remain relatively more dense than monosize packings. The consolidation of composite powder mixtures as well as microstructural evolution during HIP are also discussed. Results are compared with those predicted by modeling.
Effect of Applied Pressure of Hip on the Removal of Processing Void in Alumina Ceramics and the Resultant Improvement of Mechanical Property
Authors: Miyashita Masayori , Kim Jin-Young , Uchida Nozomu , Uematsu Keizo 
Published: March 2011

ABSTRACTAlumina ceramics prepared at various processing conditions were subjected to hot isostatic pressing (HIP) to remove processing-originated voids. Transmission optical microscope was used for characterizing voids in specimens before and after HIP, and for understanding the effect of HIP condition on the removal of void. The strengths of all specimens were measured to discuss the relation between void and strength. Voids of large size and high concentration were present in all sintered alumina ceramics. The size and concentration of void increased with decreasing pressure used in powder compaction process. HIP was found to be very effective for removing these voids which are the major processing defects in ceramics. The strength of alumina ceramics increased markedly with decreasing size and concentration of voids. The strength distribution of alumina ceramics was explained in terms of the measured void size distribution.
Containerless Hot Isostatic Processing of Titanium Diboride Ceramics
Authors: Concannon Michael , Hodge Edwin S. , Turmel Christopher 
Published: March 2011

ABSTRACTDense titanium diboride (TiB2) ceramics were fabricated by near-net processing based on containerless hot isostatic pressing. Resultant materials displayed good mechanical strength and high fracture toughness.
Tailored Microstructure and Properties through Powder Metallurgy and Hot Isostatic Pressing
Authors: Buekenhout Louis 
Published: March 2011

It is a very well known fact that there exists a narrow relationship between the structure and the properties of materials.Structure can be modified by changing the composition of the material and for a selected composition by adapting its elaboration process. Powder metallurgy (P/M) and hot isostatic pressing (HIP) can be part of the elaboration process and permit to realize mono or multi-materials with or without complex shapes which can eventually be characterized by specific properties which are not possible to be obtained through the conventional metallurgy road.The objective of this presentation is to illustrate this through a few examples.
Refinement of Electronic Ceramics by HIP
Authors: Takata Mitsuhiro , Toyota Sachio , Suenaga Yoshihiro 
Published: March 2011

ABSTRACTMnZn ferrites and PLZT with fine and uniform microstructures were prepared by hot isostatic pressing.Initial permeability of MnZn ferrites with grain size of 2.0 and 1.2 μ m was 600 at 10 MHz.An optical shutter array was made using PLZT with grain size of 2μ m. Optical transmittance was dependent upon the amount of PbO in HIP'ed PLZT. A slight deficiency of PbO in PLZT increased the transmittance at short wave length (400 nm).
Hip Phase Diagram of YBCO Type Superconductor
Authors: Sawai Yuichi , Ishizaki K. , Takata M. , Kuzjukevics A. , Narukawa Y. 
Published: March 2011

ABSTRACTThe oxygen partial pressure - temperature phase diagram of YBCO type superconductors reported before by us showed that the YBa2Cu4Ox phase formation from Y2Ba4Cu7Oz with CuO, as well as from YBa2Cu3Oy, with CuO are oxidation reactions. The total gas pressure - temperature phase diagram shows that the YBa2Cu4Ox, phase formation temperature from Y2Ba4Cu7Oz with CuO increases with increasing the total gas pressure. On this phase boundary line, the fugacity of oxygen increases with increasing the total gas pressure even at constant oxygen partial pressure.
Formation of Superconducting La2−xSrxCaCu2O6−δ Ceramic with Application of O2-HIP Technique
Authors: Oshima Kiyoshi , Watanabe Yuichi , Takata Masasuke , Ishizaki Kozo 
Published: March 2011

ABSTRACTSuperconducting La2−xSrxCaCu2O6−δ ceramics (x=0−0.6) were prepared with application of the oxygen-hot-isostatic pressing (O2-HIP) technique. The Tc of various samples was found to depend on both the Sr content and the applied oxygen partial pressure in the HIP treatment. The maximum Tc onset of 50K was observed for samples of the composition x=0.3 and 0.4 HIPped at 1050°C under 60atm oxygen partial pressure, and x=0.1 and 0.2 HIPped at 1050°C under 400atm oxygen partial pressure, respectively. From the analysis of x-ray diffraction patterns for superconducting substances, it was found that there existed a strong correlation between superconducting properties and the lattice parameters.
Polyurethane Copolymers Containing Covalently Attached RGD-Peptide: Synthesis and Cell Adhesion Studies
Authors: Lin Horng-Ban , Cooper Stuart L. 
Published: March 2011

ABSTRACTSynthesis of novel polyurethane copolymers containing covalently attached, well-oriented Arg-Gly-Asp (RGD) peptides was explored. A poly(tetramethylene oxide) based polyurethane was synthesized, and a bimolecular nucleophilic substitution reaction was then employed to incorporate ethyl carboxylate groups onto the polymer backbone. Cell-adhesive peptides Gly-Arg-Gly-Asp-Ser-Tyr (GRGDSY) and Gly-Arg-Gly-Asp-Val-Tyr (GRGDVY) were covalently bound to the polyurethane backbone via the formation of amide bonds. Nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectroscopies were used to monitor the reactions. The amount of grafted peptide was determined by amino acid analysis. Electron spectroscopy for Chemical Analysis (ESCA) suggested the presence of the grafted peptide at the polymer-air interface in vacuo. Dynamic contact angle analysis showed that, in water, the peptide-grafted polyurethane surfaces were more polar than the underivatized polyurethane. The attachment and spreading of human umbilical vein endothelial cells (HUVECs) on the underivatized and peptide-grafted polyurethanes was investigated. The GRGDSY-and GRGDVY-grafted substrates supported cell adhesion and spreading even without serum in culture medium. The GRGDVYgrafted substrate supported a larger number of adherent cells and a higher extent of cell spreading than the GRGDSY-grafted substrate. These RGD-containing peptide grafted polyurethane copolymers may be useful in providing an easily prepared cell-adhesive substrate for various biomaterial applications.
Measurement of Cell Adhesion and Migration on Protein-Coated Surfaces
Authors: DiMilla Paul A. , Stone Julie A. , Albelda Steven M. , Lauffenburger Douglas A. , Quinn John A. 
Published: March 2011

ABSTRACTThe performance of biomaterials forin vivoandin vitroapplications can depend critically on tissue cell adhesion and migration. We have been investigating the role that specific reversible interactions between cell adhesion receptors and complementary substratum-bound ligands play in the regulation of cell adhesion and migration. With an axisymmetric radial flow detachment assay (RFDA) [1] we measured cell-substratum adhesive strength for human smooth muscle cells (HSMCs) on surfaces coated with type IV collagen (CIV). We found that the critical shear stress for detachment increased linearly with increasing CIV coating concentration. Using time-lapse videomicroscopy and image analysis we tracked the movement of individual HSMCs over similar CIV-coated surfaces. Cell speed and persistence were determined for variations in CIV coating concentration by applying a persistent random walk model for individual cell movement. Cell speed reached a maximum at an intermediate concentration of CIV, supporting the hypothesis that an optimal cell-substratum adhesiveness exists for HSMC movement. This combination of techniques for measuring adhesion and motility provides a valuable tool to examine the role of cell-biomaterial interactions on cell behavior.
The Effect of Hard Segment Chemistry on the In-Vivo Biostability of Polyurethanes
Authors: Hergenrother Robert W. , Cooper Stuart L. 
Published: March 2011

ABSTRACTFour polyurethanes that were synthesized with different hard segments as well as four commercial polyurethanes were investigated for in-vivo biostability. The four polyurethanes with the varying hard segments were based on a 3/2/1/ mole ratio of methylene diphenylene diisocyanate (MDI) or methylene dicyclohexylene diisocyanate (H12MDI); butanediol (BD) or ethylene diamine (ED); and polytetramethylene oxide (PTMO) (MW=I000). Two commercial polyurethanes were also used: Biomer (Ethicon, Inc.) and Pellethane (Dow).Films of the polymers were implanted subcutaneously in rats for up to three months to assess their biostability. Polymer films were implanted with either a 100% strain applied or in the unstressed state. Measurement of tensile properties and surface properties before and after implantation was used to assess the stability of each of the polymers. Surface cracking was observed with scanning electron microscopy and the extent and depth of cracking was determined.It was found that BD chain extended polymers maintained their tensile properties better than the ED chain extended polymers after implantation. H12MDI-based polyurethanes were more susceptible to surface cracking than MDI-based polyurethanes, possibly due to the lack of a crystallizable hard segment.
Controlled Release of Fibroblast Growth Factor: Activity in Cell Culture
Authors: Nugent Matthew A. , Chen Oliver S. , Edelman Elazer R. 
Published: March 2011

ABSTRACTBasic fibroblast growth factor is a multi-potent cell regulatory factor that stimulates proliferation and angiogenesis. Controlled studies of basic fibroblast growth factor in animals have been hindered by the instability of this protein. In addition, many cells appear to require the continuous addition of basic fibroblast growth factor for optimal growth and function in culture. A system for the sustained delivery of active basic fibroblast growth factor might provide both a means to conduct log-term studies on activity and provide a practical alternative to multiple growth factor additions to cell cultures. Basic fibroblast growth factor was incorporated into standard polymer matrices, but the released growth factor had lost over 99% of its bioactivity. Loss of basic fibroblast growth factor activity was found to result from both physical inactivation and adsorption of the protein to surfaces. These problems were avoided by incorporating the growth factor into calcium cross-linked alginate microspheres containing heparinsepharose beads. Basic fibroblast growth factor was incorporated into these microspheres with 71% efficiency and active growth factor was released with predictable kinetics for up to 7 weeks. Release from these microspheres was controlled by the amount of heparin within the device and could be manipulated by simply altering the heparin content during fabrication. Alginate/heparin-sepharose microspheres were placed into growing cultures of bovine aortic endothelial cells and no cytotoxic effects were observed. Furthermore, microspheres containing growth factor provided long-term stimulation of cell proliferation and maintenance of endothelial cell morphology.
Pulsed Laser Deposition of Biocompatible Thin Films: Calcium Hydroxylapatrte and Other Calcium Phosphates
Authors: Cotell C. M. , Chrisey D. B. , Grabowski K. S. 
Published: March 2011

ABSTRACTCalcium phosphate-based ceramics were deposited on Ti, Ti-6Al-4V and Si substrates by pulsed laser deposition. The calcium phosphate phase (amorphous, α- or β-tricalciumn phosphate, tetracalcium phosphate, or hydroxylapatite), Ca/P ratio and surface morphology of the films were related to deposition conditions. At substrate temperatures <400°C, films were amorphous. Above 400°C, the gaseous environment during deposition determined the crystalline phase of the films. In O2, deposition of α-tricalcium phosphate was favored between 400 and 700°C and β-tricalcium phosphate was favored above 700°C. Films deposited in low pressures of O2 (<0.05 Torr) were P-deficient. The correct stoichiometry was approached as the pressure of O2 in the chamber during deposition increased. In water vapor-enriched inert gas environments, deposition of hydroxylapatite was observed at temperatures between 400 and 700°C and tetracalcium phosphate was observed at temperatures above 700°C. The surface morphology of hydroxylapatite films depended on the temperature of deposition. Surfaces deposited at higher substrate temperatures showed more recrystallization than those deposited at lower substrate temperatures.
Bilayer Composite Hydrogels for Corneal Prostheses
Authors: Perez Edward , Cima Linda G. , Miller David , Merrill Edward W. 
Published: March 2011

ABSTRACTA two-layer composite material composed of a thin-layer of corneal tissue and a synthetic polyethylene oxide (PEO) hydrogel is described. The material is designed to provide a suitable substrate for corneal epithelial cell growth while maintaining the desirable characteristics of hydrogels, i.e. clarity, flexibility, and ability to allow diffusive flow of nutrients. The gels are synthesized via electron irradiation induced crosslinking of an aqueous solution of PEO onto a thin layer of collagenous tissue substrate. light microscopic studies indicate that the interface between the corneal tissue and PEO gel appears well adherent with no gaps in the interface. SEM studies of the material surface show an architecture similar to that of normal corneal tissue. Surface analytical techniques were used to identify amino-acids covalently bound to the gel at the gel/collagen interface after the proteinaceous material was removed. ESCA survey scans identified the presence of nitrogen on exposed gel/collagen interfaces and amino acid labelling confirmed the presence of amino acids. ATR-IR studies identifed increased absorption for the gel collagen interfaces at 1640 cm− 1and 1540 cm−1indicative of bound amino acids.
The Influence of Molecular Structure on Apatite Adsorption
Authors: Mats S. A. Johnsson , Raj P. A. , Levine M. J. , Nancollas G. H. 
Published: March 2011

ABSTRACTThe hydroxyapatite (HAP) adsorption of salivary statherin, cystatins, proline-rich proteins and histatins has been compared to the influence of these molecules on HAP crystallization in supersaturated solution. This may yield, in many cases, information about protein conformation in the adsorbed state. The results of studies involving both parent molecules and their fragments, indicated that statherin binds to HAP primarily with a 2–5 residues segment in the N-terminal part while the cystatins and proline-rich proteins bind through a segment 2–3 times larger.