bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surface Modification of Polytetrafluoroethylene and the Deposition of Copper Films
Authors: Jiang Wenbiao , Norton M. Grant , Dickinson J. Thomas 
Published: March 2011

AbstractEnhancement of the adhesion of thin copper films on polytetrafluoroethylene substrates was found when the substrate surface was irradiated with a pulsed UV excimer laser prior to metal deposition. The interaction between the laser and the polymer was examined by characterizing the neutral and charged species emitted from the surface during irradiation. The nature of the species emitted indicates that significant chemical modification of the polymer surface occurs. In addition to chemical modification, the interaction with the laser also alters the surface morphology of the polymer. Irradiation at fluences of ∼ 0.6 J/cm2 results in an overall planarization of the surface, whilst irradiation at higher fluences results in the formation and enlargement of voids and localized melting.
Glass-Coated, Surface-Modified High-Performance Polymer Fibers
Authors: Lietzaua Christian , Farris Richard J. 
Published: March 2011

AbstractHigh-modulus PPTA and PBZT fibers have been surface-modified by a series of reactions to allow single filaments to be wetted by sodium silicate solutions as well as to exhibit good adhesion to the resulting glass coating. Fiber surfaces have been characterized by X-ray photoelectron spectroscopy. PBZT and PPTA fibers showed little or no decrease of their tensile properties as a consequence of the surface-modification. Glass coatings have been applied to single filaments by dip-coating in an aqueous sodium silicate solution followed by air- and vacuumdrying. Coated PPTA and PBZT fibers with shear moduli as high as 5 GPa have been prepared. The compressive strain at failure of PPTA filaments coated with a 0.5 μm thick air-dried coating was raised to 0.6%, compared to 0.4% for uncoated filaments.
Profiling Polyimide-Polyimide Interfaces
Authors: Stoffel Nancy C. , Kramer Edward J. , Volksen Willi , Russell Thomas P. 
Published: March 2011

AbstractThe adhesion of spuncast polyimide layers is critical to the success of manufacturing multilayer polyimide structures. We have measured the interpenetration between a spuncast layer of the meta isomer of poly(amic ethyl ester) (PAE) precursor of PMDA 4,4′ ODA and the corresponding partially-imidized PAE base layer using forward recoil spectrometry (FRES). Measurements made with FRES show that interpenetration decreases rapidly as the base layer imide fraction f increased, with a corresponding decrease in adhesion measured with a T-peel test. In the region of f > 0.8, differences in interfacial adhesion are still observed while the interfacial widths are too narrow to be differentiated with FRES. For this reason, the use of other high resolution techniques for profiling the polyimide-polyimide interface such as nuclear reaction analysis, dynamic secondary ion mass spectrometry, and neutron reflectometry will be necessary to accurately correlate interpenetration with adhesion.
Aluminum Oxide Films for Thermo-Oxidative Protection of Polyimide-Based Composites
Authors: Miller Larry M. , Gulino Daniel A. 
Published: March 2011

AbstractPolyimide-based composites offer one of the best opportunities to bring the advantages of high modulus-to-density ratio materials to higher temperature applications, such as jet engines. In the present work, thin films (1000 - 2000Å) of aluminum oxide have been deposited by plasma-enhanced chemical vapor deposition from aluminum triisopropoxide precursor on polyimide composite substrates. The films were characterized for stoichiometry, thickness uniformity, and adhesion, and their effectiveness in the prevention of thermo-oxidative degradation of the composite at temperatures up to 371 °C has been examined and compared to that provided by other thin film materials. These preliminary results indicate that Al2O3 is not as successful as SiO2 at preventing oxidative degradation, although significant variability in the quality of the polyimide composite substrate makes precise comparison difficult.
Environmental Effects on the Mechanical Behaviour of Thermoplastic Toughened Phenolics
Authors: Eccott A. R. , Arnold J. C. , Isaac D. H. 
Published: March 2011

AbstractThe environmental stress cracking (ESC) behaviour of thermoplastic toughened phenolics has been studied. As these materials have applications for ‘under the bonnet’ automotive components, testing took place in several ‘in - service’ environments and in some of the constituent chemicals as well as in air.Initial screening of the materials using three point bend testing highlighted the most hostile environments for further study. More detailed creep tests were then performed with methanol and air. ESC effects led to an increase in creep rate which relates to crack initiation. Crack initiation is lowest at intermediate levels of thermoplastic with an optimum content of about 12%. It was found that there was a significant decrease in the creep rupture lifetimes as the fraction of thermoplastic toughening agent increased. With low thermoplastic content, crack blunting becomes an important factor.
Optical Measurement of Preform Impregnation in Resin Transfer Molding
Authors: Nowak Thomas , Chun Jung-Hoon 
Published: March 2011

AbstractInfiltration of preforms used to manufacture high-performance, advanced polymer composites can lead to void formation due to inhomogeneities within the preforms. Void formation occurs at three distinct length scales: the fiber, tow and part scales. Flow visualization experiments were used to characterize void formation at the tow and fiber scales. Effects of tow-scale inhomogeneities were studied by varying the warp angle of a woven fabric. Effects of fiber-scale inhomogeneities were studied using scale models of typical tows. The experiments indicate that minimization of void content requires a trade-off between fiberscale and tow-scale void formation.
Graphite Fiber/Polyimide Composites with Improved Processability
Authors: Delvigs Peter , Klopotek David L. , Cavano Paul J. 
Published: March 2011

AbstractIn an effort to improve the processing characteristics of addition-type polyimide matrix resins, the use of flexibilized three-ring and four-ring aryl diamines was investigated. A series of fourteen diamines containing carbonyl and methylene, as well as thio connecting groups was synthesized. The diamines were polymerized with the dimethyl ester of 3,3,′4,4′-benzophenonetetracarboxylic acid, using the monomethyl ester of nadic acid as an end cap. The effect of diamine structure on the solubility and rheological properties during cure, as well as glass transition temperature and thermooxidative stability of neat resins was determined. Graphite fiber-reinforced composites were fabricated from selected resin formulations, and composite thermomechanical properties were investigated.
Photosensitive Polyamic Acids Developable with Aqueous Alkaline Solutions
Authors: Tanaka Jun , Kikkawa Haruhiko , Shoji Fusaji , Satou Hidetaka , Kataoka Fumio 
Published: March 2011

AbstractNew negative-type photosensitive polyamic acids, precursors of polyimides, developable with aqueous alkaline solutions were synthesized. Among diamine monomers having a photofunctional group, 2′-(methacryloyloxy)ethyl 3,5-diaminobenzoate yields high molecular weight polyamic acids. A photosensitive polymer composition consisting of Michler's ketone and a thermally stable peroxide, 3,3′,4,4′-tetrakis(t-butyldioxycarbonyl)-benzophenone, results in high photosensitivity. The photosensitive coating of the composition is soluble in aqueous alkaline solutions as well as in organic aprotic polar solvents and either can be used as a developer of the coating. However, resolution of the patterns is quite different especially with thick films. Solvent developers result in poor resolution whereas aqueous alkaline developers give patterns of high aspect ratio even with thick films. This is probably due to the difference in the diffusion efficiency and swelling property of the polymer to the developers.Effects of copolymerizing with an ordinary diamine monomer on photosensitivities and film properties of the polyimides derived from their precursors are also discussed.
Top Layer Oxidation In Mo/SI Multilayer X-Ray Mirror
Authors: Nguyen Khanh , Gullikson Eric , Underwood James 
Published: March 2011

AbstractReflectivity of Mo/Si multilayer x-ray mirrors with molybdenum as the top layer decreased over time when stored in air due to oxidation of the top Mo layer to MoO3 and MoO2. High reflectivity can be maintained by having silicon as the top layer. In fact, reflectivity of Si-top multilayer coatings increase slightly during the first few days after deposition.
Fast Dosimeter Film For Evaluation Of X-Ray Lithography Sources
Authors: Maldonado Juan R. , Pomerene Andrew 
Published: March 2011

AbstractThis paper presents data on the soft x-ray behavior of the photochromic dosimeter film UVSC manufactured by Sensor Physics. In particular, the x-ray sensitivity measured with synchrotron storage ring x-ray sources will be presented and compared with a presently used dosimeter film which is many times less sensitive. Relevant properties of the film for x-ray source evaluation also will be presented together with data obtained with other x-ray lithography sources.
Characterization Of Boron Films Prepared By Chemical Vapor Deposition And Their Application In X-Ray Imaging
Authors: Yuan Fang , Allred David D. 
Published: March 2011

AbstractBoron, a low Z element, is useful for x-ray optics since it has a low atomic absorption coefficient. Boron films prepared by chemical vapor deposition were characterized optically, electronically and mechanically. Auger, infrared and hydrogen effusion analyses showed that the films are amorphous hydrogenated boron. The hydrogen content ranges from 8–71%. The measurements of the complex refractive index and the resistance vs. temperature determined that they are a typical amorphous semiconductor with the energy gap ranging from 1.09 to 1.36 eV, decreasing with increasing hydrogen content and with the Fermi energy level pinned about midgap. The real refractive index at 490 nm increases from 3.25–3.59 with increasing hydrogen content. The Young's modulus and hardness were found to be 3.05 × 1013 dyne/cm2 and around 2500 Vickers, respectively. The chemical tests suggested that boron films are stable in nonoxidizing bases and concentrated acids. Some oxidizing bases such as basic ferricyanide and permanganate solutions are good etchants for CVD boron films. Boron coated beryllium x-ray windows which have enhanced resistance to degradation are now commercially available, and self-supporting boron windows are potential future products for x-ray imaging.
Ionization Radiation Effects And Mechanisms
Authors: Vladimirsky Yuli , Scott John D. , Bhattacharya Pradeep K. 
Published: March 2011

AbstractA systematic approach for predicting radiation stability of materials and devices is presented. The conceptual basis is a consideration of the radiolysis potentially occurring in x-ray-irradiated materials as a multi-stage process: a) primary radiation excitations (PRE); b) secondary generation of isolated electronic and structural defects resulting from PRE relaxation; and c) interaction, accumulation, and coagulation of defects resulting in change of device electronic properties and in degradation of optical material. This predictive technique involves specific relevant information in a relatively simple context for the purpose of modeling the radiolysis process. It should find general application in selecting materials for x-ray optical elements such as masks, filters, windows where resistance to radiolysis is required as well as for photoresists where radiolytic sensitivity is necessary.
LPCVD Of Silicon Carbide Films From The Organosilanes Diethylsilane And Di-T-Butylsilane
Authors: Levy Roland A. , Grow James M. 
Published: March 2011

AbstractIn this paper, the kinetics and properties of amorphous LPCVD silicon carbide films synthesized from the single organosilane precursors diethylsilane (DES) or di-tbutylsilane (DTBS) are discussed. For DES, the growth rate is observed to vary linearly with flow rate and pressure, while for DTBS, a square root dependency is seen as a function of these parameters. An Arrhenius type behavior was observed for both chemistries yielding activation energy values of 40 and 25 kcal/mol for DES and DTBS respectively. The elemental composition of the films became progressively richer in carbon as the deposition temperature increased with stoichiometry occurring near 750°C. The film stress was dependent on carbon content and became compressive at compositions near Si0.35C0.65. The hardness and Young's modulus of the films increased with increasing carbon content reaching maxima near stoichiometry. Free-standing membranes produced under optimal processing conditions had a relatively low optical transmission due to excess carbon. Although, transmission characteristics were improved by adding NH3 in the reaction chamber, the resulting silicon carbonitride films exhibited undesirably high values of tensile stress.
Multilayer Membranes For X-Ray Lithography
Authors: Shimkunas Alex R. , Mauger Philip E. , Bourge Lawrence P. 
Published: March 2011

AbstractMultilayer x-ray lithography membranes were designed and fabricated. Consisting of alternating layers of SiC and SiNx, the membranes were designed to have low reflectance for improved optical alignment of x-ray masks, high fracture strength, superior chemicaletch resistance, and high manufacturing yield. The membranes were prepared from multilayer coatings deposited on silicon wafers in an electron cyclotron resonance chemical vapor deposition system. Membranes with less than 5% reflectance over 150 nm bandwidths were made. External SiNx layers increased the chemical etch resistance of the membranes. The fracture strength was 2–3 times that of SiC, and the membrane yield was 50% higher than that of single-layer SiC. Field-emission SEM of the multilayer coating cross-section showed the presence of 20–150 nm defects near the layer interfaces. The layering confines or stabilizes the defects, thereby increasing the membrane yield and fracture strength.
Effects of Simulated X-Ray Lithography Exposures On Submicron-Channel Mosfets
Authors: Lelis A. J. , Oldham T. R. 
Published: March 2011

AbstractInvestigations of submicron-channel-length n- and p-channel MOSFETs subjected to channel hot-carrier stressing were performed, comparing the reliability of devices with and without exposure to simulated x-ray lithography processing steps. No significant differences were observed between the sample groups.
Contactless Evaluation Of The Stress In X-Ray Mask Wafers (SiN/Si) Using A Laser/Microwave Method.
Authors: Oda Masatoshi , Usami Akira , Nakai Takahisa , Ito Akira , Ichimura Masaya , Wada Takao 
Published: March 2011

AbstractHighly accurate X-ray masks are strongly required to establish SR lithography technology. X-ray masks must be produced as accurately as the LSI devices, because a one-toone projection aligner system is used. To minimize the in-plane mask distortion, it is desirable to estimate the value of the stress and the non-uniformity in the membrane fabrication (SiN) process. The values of the stress were estimated from the measurement of the warpage and the calculation. It is very difficult to obtain the stress distribution in the SiN/Si wafer. Thus, we measured the minority carrier lifetime distribution using the non-contact laser/microwave method. The carrier injection was done by a 774nm or 904nm semiconductor laser diode, and their beam was focused to about 500 μmφ. The surface lifetime, τ s, of the SiN/Si wafer with the stress over ˜ 108dyn/cm2 decreased to 60–70% of that of the bare Si wafer. Thus, the contactless laser/microwave system can be adaptable for the characterization in the X-ray mask process.
Polycrystalline Diamond Films for X-Ray Lithography
Authors: Whitehair S. J. , Yehoda J. E. , Fuentes R. , Roy R. A. , Guarnieri C. R. , Cuomo J. J. 
Published: March 2011

AbstractMicrowave driven discharges are finding increasing use in semiconductor areas such as deposition, etching, cleaning and ashing. One application that is of particular interest is the use of microwave discharge grown thin film diamond as a x-ray mask. Because of diamonds extreme properties these masks offer potential advantages over current silicon based mask technology. A review of diamond mask technology will be presented and compared to competing technologies.
Synchrotron Radiation for Measurement of Contaminants on Silicon Surfaces
Authors: Madden Michael C. , Wherry David C. , Pianetta Piero , Brennan Sean 
Published: March 2011

ABSTRACTThe detection limit for aluminum using total reflection x-ray fluorescence (TXRF) is approximately 100 times lower for a synchrotron source compared to a conventional source. The detection limit for transition metals is approximately 15 to 40 times lower depending on atomic number and energy of the incident radiation.
X-Ray Analysis of Multilayer Structures
Authors: Kushnir V. I. , Georgopoulos P. 
Published: March 2011

ABSTRACTA new technique of obtaining layer thickness and internal strains in multilayer structures and quantum wells from the rocking curve data is described and analytically proved. This method consists of Fourier transform of the experimental intensity profile multiplied by the wave vector deviation squared. It is shown that peaks of the Fourier transform correspond to distances between boundaries in the specimen. The (400) reflection curves of a quantum well in InP/InAs and a superlattice structure made up of latticematched GaAs/Ga0.49 In0.51P layers were measured with 8 KeV radiation at beamnline X-18A, National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory. The results of above procedure were used to reduce a number of degrees of freedom in a computer simulation of reflecting curves. It is shown that it is possible to extract layer thicknesses with the accuracy of about 15 Å for thick layers to as low as 1 Å for superlattices. Interplanar distances can be obtained with an accuracy of 0.0001 Å.
Investigation of Filamentation Damage Resulting from Electromagnetic Breakdown in Si Bi-Polar Diodes
Authors: Wang S. , Dudley M. , Fazi C. , Gordon-Smnith D. 
Published: March 2011

ABSTRACTSynchrotron white beam X-ray topographic studies of damage induced during the R-F electromagnetic breakdown of bi-polar diodes on silicon have been carried out. Filaments associated with damage processes in reverse bias, have been observed close to the surface of the Si epilayer, using the surface sensitive grazing Bragg-Laue technique. Ray-tracing experiments have enabled us to determine the exact lateral location of the filament to be at the edge of the metallization region, at the junction between it and the metallic contact. The influence of these results on hardening technologies is discussed.
Atomic Structure Studies of Zirconia Solid Solutions by EXAFS
Authors: Chen I-Wei , Li Ping , Penner-Hahn James 
Published: March 2011

ABSTRACTWe have investigated, using EXAFS, the local atomic structures of four zirconia polymorphs and their solid solutions with Ca2+, Ga3+, Fe3+, y3+, Gd3+, Ge4+, Ti4+, Ce4+ and Nb5+. Structural information up to 9Å, and in one special case up to 10.9Å, from the absorbing atom has been obtained. The characteristic features of local environments of both the host Zr and the dopant cations, and their variations leading to cation ordering and symmetry evolutions, are elucidated in terms of a dopant size effect and an oxygen vacancy effect. The dynamic aspects of the EXAFS Debye-Waller factor are used to shed light on the connection between phase transition, dopant stabilization, and cation-anion correlation.
Diffraction of Fe/Cr using Anomalous Dispersion Enhancement
Authors: Foiles C. L. , Loloee R. , Rahman Sharif M. 
Published: March 2011

ABSTRACTResults for a study using anomalous scattering to increase the X-ray contrast between Fe and Cr in metallic multilayers are reported. This increased contrast is sufficient to provide reliable values for actual bilayer distances and to begin semi-quantitative analysis of peak intensities even in the presence of orientational texture.
Simultaneous, Time-Resolved, Saxs/Waxs Studies on Block Copoly(Ether-Urethane) Phase Behaviour
Authors: Bras W. , Derbyshire G. E. , Greavest G. N. , Mantt G. R. , Naylor S. , Ryan A. J. 
Published: March 2011

ABSTRACTA new experimental technique for the characterisation of the thermal-morphological properties of materials has been developed at Daresbury. Many thermal events, for example melting endotherms, are signals of changes in morphology covering size scales from the atomic to the microscopic, that is Å to μm. There are obvious advantages in collecting both the wide angle (1-20Å) and small angle (20-1000Å) patterns simultaneously to unambiguously characterise such thermal events. The new apparatus comprises a Linkam hot-stage capable of controlled heating and cooling mounted in a combined SAXS/WAXS camera. The camera is equipped with a multiwire quadrant detector (SAXS) located 3.5 m from the sample position and a curved knifeedge detector (WAXS) that covers 120° of arc at a radius of 0.4 m. SAXSIWAXS is possible with a time resolution of 0.1 seconds and heating/cooling rates up to 120 °C min-1.
Speciation of Uranium After Microbial Action by XANES and XPS
Authors: Dodge Cleveland J. , Francis A. J. , Lu F. , Halada G. P. , Kagwde S. V. , Clayton C. R. 
Published: March 2011

ABSTRACTThe speciation of radionuclides and toxic metals in wastes subjected to microbial action is important in determining the extent of stabilization in a disposal environment. As part of an ongoing study, we investigated the reduction of uranium by aClostridiumsp. using X-ray absorption near edge spectroscopy (XANES) at the National Synchrotron Light Source (NSLS) and X-ray photoelectron spectroscopy (XPS). XPS analysis of uranyl acetate containing hexavalent uranium exhibited a binding energy of 382.0eV at the U 4f7/2peak. The sample incubated in the presence of bacteria was shifted to lower binding energy (380.6eV), confirming the reduction of U6+to U4+at the bacterial surface. XANES analysis, using an electron yield detector, was performed at the Mv absorption edge (3d--> 5f). The absorption peak energy of the sample exhibited a shift from 3551.1eV to 3550.1eV which is higher than uranium metal (3549.6eV) but lower than U4+(3550.4eV). This indicates the presence of U3+which is probably located beneath the surface within the biomass. Anaerobic bacterial treatment of wastes containing uranyl ion can result in the stabilization of uranium.
Micro-Impact Technique and its Applications
Authors: Wu T.W. , Lee C.-K. , Wang R.H. 
Published: March 2011

ABSTRACTA micro-impact tester has been designed and built by using a piezoelectric impact hammer as an impactor driver. During the course of an impact process, force interactions between the impactor and target surfaces were monitored continuously by a miniaturized piezoelectric loadcell embedded in the flying head assembly. After having fully characterized an impact system, the trajectory of the impactor can be calculated by using the corresponding pre-recorded impact force interaction in the simulation program. The contact and returning velocities, kinetic energy loss of the impactor and the impact penetration curve are the key information obtained from the simulation. Furthermore, the impact morphology can reveal failure mechanisms of materials by providing details such as indent shapes, coating fragments, chipping, crack type and size, and other such information which are useful in assessing the fracture toughness of testing materials. The micro-impact testing was carried out in the contact velocity ranging from 0.3 to 2.0 m/sec. Three types of materials such as metal, glass and amorphous carbon were used in studying their distinct mechanical behavior under high rate indentations. The correlations between the impact conditions, energy losses, impact morphologies and material responses are illustrated and discussed.