bluuebunny/crossref_metadata_2025_split huggingface dataset:
Elastic Properties of Diamond Like Carbon Thin Films: a Brillouin Scattering Study
Authors: Monteiro O. R. , Brown I. G. , Sooryakumar R. , Chirita M. 
Published: June 2019

AbstractDiamondlike carbon (DLC) thin films have been widely used as hard coatings in a variety of applications where increased wear resistance and hardness are required. Vacuum arc DLC films are among the hardest, with measured hardness values of up to 68 GPa. In our deposition process a repetitively pulsed bias voltage is applied to the substrate, which controls the energy of the incoming C ions. DLC chemical and mechanical properties are strongly affected by the energy of the depositing ions. In this paper, we relate the mechanical properties of these films to the deposition parameters, and describe our initial Brillouin scattering measurements of the elastic constants of monolithic DLC films. Evidence for bulk longitudinal and surface Rayleigh excitation in films with thickness of 50 and 500 nm has been observed. Since the DLC films are amorphous, they are modeled as isotropic solids and the elastic constants CII and C44 are derived.
Surface Treatment with UV-Excited Radicals for Highly-Reliable Gate Dielectrics
Authors: Ito Takashi , Sugino Rinji , Nakanishi Toshiro , Ohkubo Satoshi , Tamura Yasuyuki , Takasaki Kanetake 
Published: June 2019

ABSTRACTThe UV-excited chlorine radical treatment effectively removed trace metal contaminants from Si ans SiO2 surfaces. We have found that this is predomonantly attributed to reactions between metal and chlorine, and metal oxides and silicon chloride, respectively. The former process was subjected to identify a breakdown spot on a thin gate dielectric film. After dielectric breakdown, a silicon crystallized filament as small as a few nanometers in diameter was formed and was selectively etched with chlorine radicals revealing a successively-etched region of the Si substrate. Nonuniformi t i es of native oxides on silicon were also detected using the same method. Gettering and etching with a poly Si layer showed a possibility to make a gate dielectric film damage free and contamination free. Densi fication of native oxides formed after conventional wet cleaning of silicon was made with UV-excited oxygen radicals. Electrical characteristics of gate dielectrics treated with UV-excited chlorine and oxygen radicals showed high reliability.
Progressive Debonding of Multilayer Interconnect Structures
Authors: Lane Michael , Ware Robert , Voss Steven , Ma Qing , Fujimoto Harry , Dauskardt Reinhold H. 
Published: June 2019

ABSTRACTProgressive (or time dependent) debonding of interfaces poses serious problems in interconnect structures involving multilayer thin films stacks. The existence of such subcriticai debonding associated with environmentally assisted crack-growth processes is examined for a TiN/SiO2 interface commonly encountered in interconnect structures. The rate of debond extension is found to be sensitive to the mechanical driving force as well as the interface morphology, chemistry, and yielding of adjacent ductile layers. In order to investigate the effect of interconnect structure, particularly the effect of an adjacent ductile Al-Cu layer, on subcriticai debonding along the TiN/SiO2 interface, a set of samples was prepared with Al-Cu layer thicknesses varying from 0.2–4.0 μm. All other processing conditions remained the same over the entire sample run. Results showed that for a given crack growth velocity, the debond driving force scaled with Al-Cu layer thickness. Normalizing the data by the critical adhesion energy allowed a universal subcriticai debond rate curve to be derived.
Thermal and Electromigration Strain Distributions in 10 μm-Wide Aluminum Conductor Lines Measured by X-Ray Microdiffraction
Authors: Wang P.-C. , Cargill G. S. , Noyan I. C. , Liniger E. G. , Hu C.-K. , Lee K. Y. 
Published: June 2019

ABSTRACTX-ray microdiffraction was applied to study the thermal and electromigration strains in 10 μm-wide Al conductor lines with 10 μm spatial resolution. X-rays were collimated either by pinholes or by tapered glass capillaries to form x-ray microbeams. Measurements were made in a symmetric-reflection geometry so that the strains normal to the sample surface could be examined at different positions along the conductor lines. Results of thermal strain measurements show that the SiO2 passivation plays an important role in limiting relaxation of in-plane compressive thermal stresses in the Al lines, but that the passivation is not effective in confining the overall thermal expansion of the Al line along the film normal. Electromigration strain measurements show that a linear stress gradient developed within the first hour of electromigration. The magnitude of the stress gradient changed little until fast stress relaxations occurred near the anode end of the line. Possible mechanisms are discussed in light of these observations.
White Light Emitting Electroluminescence Devices with Organic Oligomers
Authors: Meghdadi F. , Tasch S. , Graupner W. , Döttinger S.E. , Hanack M. , Graupner M. , Hermetter A. , Leising G. 
Published: June 2019

AbstractWe report on the properties of white light emitting electroluminescence (EL) devices fabricated by combining blue and orange light emitting organic materials, parahexaphenyl (PHP) and a new isothianaphthen-S-oxide (ITSO) oligomer. The EL spectrum of this oligomer blend covers the range from 400 to 650 nm. When the concentration ratios of these materials are suitably adjusted a pure white light emission (CIE coordinates of x=0.333 and y= 0.338) and a high external EL quantum efficiency of 1.2% photons/electron can be obtained. The mechanism of the white light generation is ascribed to an internal self-absorption of part of the blue PHP light emission by ITSO and a subsequent photoluminescence emission process of ITSO. The results of photoinduced absorption, which is sensitive to charged species and triplet states of these guest-host systems, are discussed.
The Leaching Of The Reactive Powder Concretes: Results On Transfer Properties
Authors: Matite V. , Moranville M. 
Published: June 2019

ABSTRACTThe properties of concrete can be altered in aggressive media such as pure water. A leaching test was performed for Reactive Powder Concretes (RPC) in order to evaluate their durability when used as storage of nuclear wastes. Emphasis is placed on the changes of their microstructure, on the tritium diffusion coefficient and on the porosity after leaching. Using mainly non destructive techniques such as SEM, BET and diffusion cell, we found that the leaching affects the RPC microstructure, particularly the anhydrous cement grains. The tritium diffusion coefficient, even lower than that of granite, is however ten times higher after a three month-leaching.
Ultrasonic And Magnetic Techniques For Materials Characterization And Embrittlement Detection
Authors: Thompson R. B. , Igarishi B. , Alers G. A. 
Published: June 2019

ABSTRACTThis paper contains a brief description of recent research advances aimed at the nondestructive characterization of embrittlement, followed by a more detailed discussion of some recent results. The former includes recommendations in the areas of nondestructive evaluation and broader strategies for assessing embrittlement of irradiated reactor pressure vessel steels. The latter describes some very recent results in using measurements of dynamic magnetostriction to monitor the ultra fine scale microstructural changes associated with embrittlement.
Non-Destructive Evaluation of Deformation and Fracture Properties of Materials using Stress-strain Microprobe
Authors: Murty K. L. , Mathew M. D. , Miraglia P. Q. , Shah V. N. , Haggag F. M. 
Published: June 2019

ABSTRACTTensile deformation and fracture properties of several metallic materials, welds, and their heataffected-zones were determined non-destructively using the Stress-Strain Microprobe (SSM) system. The system is based on automated ball indentation (ABI) technique and involves straincontrolled multiple indentations at the same location on the material surface by a small spherical indenter. The technique permits evaluation of tensile deformation parameters such as yield strength, ultimate tensile strength, strength coefficient, and strain-hardening exponent, and a fracture energy parameter called indentation energy to fracture. ABI tests were conducted on carbon steels, stainless steels, nickel alloys, aluminum alloys, Zircaloys, electronic soldering materials and several nuclear pressure vessel steels (in the unirradiated, neutron irradiated, and irradiated and thermally annealed conditions). For all these test materials and conditions, the ABI-derived results were found to agree with the data from conventional standard test methods. In addition to the laboratory applications of SSM, it can be used as an in-situ testing instrument for non-destructive assessment of deformation and fracture properties of operating structural components.
Gan Nucleation Mechanism on A Surface Template of Oxidized AIAs
Authors: Kobayashia Nobuhiko P. , Kobayashia Junko T. , Choib Won-Jin , Dapkusa P. Daniel 
Published: June 2019

ABSTRACTThe surfaces of oxidized AlAs (AlOx) layers on Si(111) substrates are studied to understand the mechanism by which single crystal α-GaN can be grown by metalorganic chemical vapor deposition (MOCVD) on AlOx that appears to be an amorphous/fine-grain phase. Contact mode atomic force microscopy (C-AFM) and reflection high energy electron diffraction (RHEED) are used to study the AIOx surface on which a GaN nucleation layer (GaN-NL) is grown. The results indicate that an oriented α-Ga2O3 layer is formed on AlOx which is covered by a GaAs cap layer during oxidation. We infer that the α-Ga2O3 acts as a surface template that provides the order necessary for the subsequent growth of single crystal α-GaN. Characterization using RHEED and selective area electron diffraction (SAD) in cross sectional transmission microscopy (XTEM) reveals that the in-plane crystallographic orientation has a unique alignment between the various layers – GaN, α-Ga2O3 and the Si substrate. This in-plane alignment is understood by considering the atomic arrangement of each material on the plane perpendicular to [111]si at each interface. Moreover a comparison is made between α-GaN grown on α-Ga2O3 and on α-A12O3(0001) to characterize structural defects in α-GaN. The formation of specific structural defects, a large number of planar defects run perpendicular to [111]si in α-GaN/α-Ga2O3 is discussed in conjunction with GaN-NL on α-Ga2O3.
Analysis Of Sige Fet Device Structures On Silicon-on-sapphire Substrates by X-Ray Diffraction
Authors: Mooney P. M. , Chu J. O. , Ott J. A. , Jordan-Sweet J. L. , Meyerson B. S. , Dubbelday W. B. , Lagnado I. , Kavanagh K. L. 
Published: June 2019

AbstractSi/Si1-xGex, heterostructures on improved silicon-on-sapphire substrates were grown epitaxially by ultra-high vacuum chemical vapor deposition for application as p-channel field effect transistors. High-resolution triple-axis x-ray diffraction was used to analyze these structures quantitatively and to evaluate the effects of device fabrication processes on them. Out-;diffusion of Ge from the Si1-xGex, quantum well was observed after fabrication as was the change in thickness of the Si cap layer due to wafer cleaning and gate oxidation at 875 °C
What can we Predict Before it's Implanted?
Authors: Gibbons Donald F. 
Published: June 2019

ABSTRACTThe material factors which relate to the degradation and/or leaching of ions or molecules are described and the possible biological pathways which they may activate are described, i.e. cytotoxic, immune, tumor and nonspecific inflammatory response. Cytotoxicity is the only biological response which may be measured with high sensitivity by an in vitro assay prior to implantation. All other biological pathways require some degree of in vivo involvement. Three examples of biological response to material factors associated with devices which require evaluation by in vivo assays are discussed, namely: surface topology (texture), mechanically induced factors at the device/tissue interface caused by differences in compliance, and dystrophic calcification in connective tissue and vascular devices.
Ultrahigh Molecular Weight Polyethylene in Total Joint Components
Authors: Wright Timothy M. , Rimnac Clare M. , Bartel Donald L. 
Published: June 2019

ABSTRACTThis article reviews the problem of ultrahigh molecular weight polyethylene component surface degradation in total hip and total knee prostheses, including its clinical implications. Several factors affecting surface damage have been identified from a combination of the observations of in-vivo degradation made on retrieved components, experimental measurement of contact stresses on polyethylene components as a result of contact with their metallic counterpart, and analytical studies of both contact stress and the stresses beneath the polyethylene surface. Both the observations of in-vivo surface degradation and the analytical studies demonstrate that surface degradation is a more severe problem in total knee replacements than in total hip replacements. The performance of polyethylene components, as affected by design factors such as material thickness and material modification, is also considered.
Comparison of Wear resistance of Ion Implanted Surgical Ti-6Al-4V with Other Alloys
Authors: Jianqiang Zhang , Xiaozhong Zhang , Zintang Guo , Hengde Li 
Published: June 2019

ABSTRACTThe wear resistance of N-ion implanted titanium, N-ion implanted Ti-6Al-4V alloy, ion plated Ti-6A1-4V, ion nitrided Ti-6Al-4V and surgical Co-Cr-Mo alloy were studied. All were studied under similar conditions, including dry wear and wear with lubricants of distilled water, saline solution, and human plasma. The results favor use of ion implanted Ti-6Al-4V alloy.
Stimulation Electrodes Based on MnO2 Thin Films: Electrical Properties in Carbonate Buffered Saline
Authors: Kelliher Ellen M. , Rose Timothy L. 
Published: June 2019

ABSTRACTHydrous manganese dioxide films are being investigated as a new redox material for the active surface of intracortical stimulation electrodes. The films are electrodeposited at room temperature on Pt substrates from a neutral solution of manganese acetate. The electrochemical properties of the films have been evaluated by cyclic voltammetry in neutral saline solutions buffered with bicarbonate. The films undergo a reversible charge injection reaction represented asThe results obtained in electrolytes of different buffer concentrations indicate the film is able to store the most charge in solutions having the lowest buffer capacity. The kinetics of the redox reaction thus favor operation in an acidic or basic environment in agreement with earlier published results. Two different mechanisms are proposed to explain the rate enhancement at the different pH's. In acidic electrolytes the reaction proceeds by dissolution of the film, while in alkaline solutions the rate determining step of proton diffusion in the solid film is increased. For neural stimulation, therefore, electrodes with manganese dioxide films should be pulsed cathodically to insure a neutral or alkaline environment around the electrode and minimize dissolution of the film.
Biomaterials-Associated Pathology of Cardiac Valve Prostheses: Clinical Explant Analysis and Studies of Tissue Valve Calcification
Authors: Schoen Frederick J. , Levy Robert J. 
Published: June 2019

ABSTRACTStudies of the pathology of explanted clinical and experimental valve specimens were done to determine the role of biomaterials in the failure of heart valve prostheses. From 7/80 through 12/84, 129 patients had valve prostheses removed at our hospital. Thrombosis/thromboembolism was the most frequent cause of the 39 mechanical valve failures (23%). Structural failure (poor durability) caused 12%. In contrast, with tissue-derived bioprostheses (90 patients), primary tissue degenerative failure was frequent (70%), and was usually associated with calcification (CALC). Infection caused 19% of all valve failures with a frequency not differing among valve types. Other causes of failure were not biomaterials-related. Thus, although frank materials degradation necessitates only a minority of mechanical valve removals, the suboptimal biologic properties of contemporary heart valve biomaterials contribute to some frequent complications (such as thrombosis/thromboembolism). Furthermore, degeneration due to mineralization is the overwhelming mode of failure of bioprosthetic valves.To understand and potentially eliminate bioprosthetic valve CALC, the kinetics, morphology and host and implant determinants of this process were studied using subcutaneous implants in rats. In this model, in which the pathologic features were similar to those of actual experimental and clinical valve replacements, CALC of glutaraldehyde-treated porcine aortic valve and bovine pericardium began within 48 hours following implantation; mineral levels were comparable to those in failed clinical valves after 84–126 days. Calcific deposits were initially associated with connective tissue cells, but later involved collagen. Systemically-administered ethane-hydroxy-diphosphonate (EHDP), a drug used to treat some forms of metabolic bone disease, inhibited CALC by 97%, but caused significant bone growth retardation. However, EHDP given by site-specific controlled-release largely mitigated CALC at only 1% of the total effective systemic dose, but without adverse effects.
Spectroscopic Ellipsometry Studies of Giaever Immunology Slide
Authors: Yang B. , Kim S. Y. , Vedam K. 
Published: June 2019

ABSTRACTSpectroscopic ellipsometry has been used to study the dielectric response of indium film evaporated on a glass substrate, as well as that of indium film adsorbed with monolayers of Bovine Serum Albumin (BSA) and Rabbit Antiserum on BSA (RABSA). It is found that the position of the ε2peak (or the peak of the imaginary part of the complex dielectric function) shifts to longer wavelengths and also increases in height as monolayers of BSA and RABSA are successively adsorbed onto it. The observed peak changes are due to the adsorption of BSA and RABSA on the surface of prolate indium clusters, which in effect increases the effective refractive index of voids between indium islands from 1.0 to 1.075 (BSA) and 1.15 (BSA + RABSA).
Light and Scanning Electron Microscopy of Human Spinal Ligaments
Authors: Yahia L.-H. , Drouin G. , Rivard C.-H. 
Published: June 2019

ABSTRACTSpinal ligaments were obtained from normal and scoliotic individuals. Detailed morphological studies were carried out on the yellow, interspinous and supraspinous ligaments by light and scanning electron microscopy. Normal yellow ligaments are mostly constituted of dense elastin fibers with only a few collagen fibers and sparse blood vessels, while in normal interspinous and supraspinous ligaments, the presence of collagen is highly dominant. In the latter structures, the collagen fascicles are characterized by a regular waviness morphology. The fibrils constituting the fascicles appear either parallel or helical with respect to the fascicle axis. Structural changes are observed in the spinal ligaments of patients with congenital as well as idiopathic scoliosis. For yellow ligaments, only slight differences are found between normal and scoliotic specimens. However, alterations in collagen waviness and architecture are observed mainly in the supraspinous ligaments and to a lesser extent in the interspinous ligaments. In addition, increases in the cellularity, loose connective tissue and vessels are found in both forgoing ligaments. These results indicate that the more pronounced scoliosis-related changes occur in ligaments having the farthest distance from the axis of flexion-rotation.
Technique of surface control with the Electrolyzed D.I.water for post CMP cleaning
Authors: Shirakashi Mitsuhiko , Itoh Kenya , Katakabe Ichiro , Kamezawa Masayuki , Kihara Sachiko , Tsujimura Manabu , Saitoh Takayuki , Yamada Kaoru , Miyashita Naoto , Kodera Masako , Matsui Yoshitaka 
Published: June 2019

AbstractChemical mechanical planarization (CMP) has been widely used for planarization of ILD, STI, plug and wiring processes. In post metal CMP cleaning processes, there are still many problems to be solved. There are several surfaces of materials, such as wiring materials, barrier materials, dielectric materials etc., on the wafer that must be cleaned at the same time,. It is also important to clean these different surfaces without any chemical or mechanical damage. We have confirmed that the Electrolyzed D.I.water is effective in post CMP cleaning for controlling the surface condition during cleaning and leaving a robust surface after CMP. We describe the Electrolyzed D.I.water system and present some results on the cleaning capability and control of the metal surface for application to cleaning after a metal CMP process.
Scaling Theory for End-Functionalized Polymers Confined Between Two Surfaces
Authors: Kuznetsov Dmitri V. , Balazs Anna C. 
Published: June 2019

ABSTRACTUsing scaling theory, we determine the equilibrium behavior of a melt of functionalized and non-functionalized polymers confined between two infinite, planar surfaces, which model clay sheets. The functionalized chains contain two end-groups (one at each chain-end) that are highly attracted to the surfaces. Through these calculations, we delineate the conditions for the formation of thermodynamically stable polymer/clay mixtures in terms of the end-group adsorption energy, volume fraction of the end-functionalized chains, and polymer chain lengths.
Interfacial Adhesion of Biopolymer Gels Measured using the Peel Test.
Authors: Pomfret S.J. , Plucknett K.P. , Normand V. , Frith W.J. , Norton I.T. 
Published: June 2019

ABSTRACTThe adhesion between layers of biopolymer gels has been measured using the 90-degree peel test. Gel bilayers, including gelatin, agarose, maltodextrin and κ-carrageenan, were prepared in two ways – simple contact between two pre-gelled layers and layers being cast on top of one another. The force required to separate these layers was measured and the results allow the interfacial properties to be compared as a function of gel type, preparation method used, and layer contact time. A value of approximately 0.2 J/m2 for the interfacial fracture energy is found for a maltodextrin/gelatin interface formed by casting gelatin on maltodextrin. This is in good agreement with values indirectly observed from particle/matrix debonding experiments performed on composite systems.