bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental Investigation of Sodium Bentonite Stability in Hanford Basalt
Authors: Wood M. I. 
Published: March 2011

ABSTRACTSodium bentonite is a candidate material for the waste package backfill component in a repository in basalt at the Hanford Site. Preliminary hydrothernmal experiments have been conducted under near-field geochemical conditions expected to occur in the reference repository location in the Grande Ronde Basalt. Experiments have been conducted in the basalt/groundwater, bentonite/groundwater, and basalt/bentonite/groundwater systems. The experiments have been conducted at 300°C using a simulated Grande Ronde groundwater, reference Umtanum basalt, and sodium bentonite. Key data generated by the experiments include experimental solution analyses as a function of time and preliminary solids analysis by scanning transmission electron microscopy and X-ray diffraction. Solution trends of the major aqueous species were similar in the three systems and are characterized by: (1) the gradual reduction of the pH value from ∼9.75 to a steady-state value of ∼6, (2) an initial rapid increase followed by a gradual decrease in silica concentration, and (3) a slight or negligible increase in sodium, sulfate, and chloride concentrations. In the bentonite/groundwater experiment, small amounts (<1%) of an albite reaction product were observed. Conversely, the formation of illite, a common bentonite alteration product, was not observed. These results indicate that sodium bentonite will remain sufficiently stable at 300°C under hydrothermal conditions in basalt to permit its use as a backfill material.
Ion Beam Processing of Optical Thin Films
Authors: Gibson U. J. 
Published: March 2011

ABSTRACTThe microstructure and optical properties of vacuum evaporated coatings are a sensitive function of the deposition conditions. In recent years, ion bombardment has been used increasingly for the production of denser, more stable coatings of oxides and other materials. In addition to modifying the microstructure, ion bombardment is emerging as a valuable tool for altering the composition (and hence the optical properties) of thin films. A discussion of the effects of ion beam processing and the methods used to analyze the changes in these films is presented.
Correlation Between Optical Absorption and Refractive Index of Silica and Silicate Glasses Implanted with Copper
Authors: Weeks R. A. , Hosono H. , Zuhr R. , Magruder R. , Mogul H. 
Published: March 2011

ABSTRACTThe refractive indices and optical absorptions of Cu implanted glasses have been measured. Silica and two silicate glasses have been implanted with Cu+ to nominal doses ranging from 3×1015 cm−2 to 6×1016 cm−2 at an energy of 160KeV and currents of ∼4μAcm−2. Substrate temperatures, during implantation, ranged from ∼100K to 700K. Both refractive index and optical absorption of the silica are functions of dose and substrate temperature. Neither of these properties are significantly altered in the silicate glasses for any dose or substrate temperature. The observed increases in the index of the implanted silica are attributed to an optical band due to Cu0 colloids.
Ion Irradiation Damage In MgAl2O4 and Al23O27N5 Ceramics
Authors: Knight P. A. , Jenkins M. L. , Pells G. P. 
Published: March 2011

ABSTRACTPolycrystalline magnesium aluminate spinel (MgAl2O4) and Al23O27 N5 (ALON) were irradiated with 4 MeV Ar+ ions to doses from 0.5 to 6 displacements per atom (dpa) at a temperature of 1070K and subsequently examined using transmission electron microscopy. Faulted dislocation loops were found in both materials, although their habit planes ({110} and {111} respectively) and Burgers vectors (a/4 <110> and a/6 <111>) differ. Cavities were found in spinel but not in ALON. Both materials exhibited a similar, low, degree of radiation damage and we conclude that polycrystalline ALON is a good potential reactor window material.
Ion-assisted Laser Deposition of CaF2thin Films onto Ccold Substrates
Authors: Gluck N. S. , Sankur H. , Gunning W. J. 
Published: March 2011

ABSTRACTThin CaF2films were grown at low temperatures (20°C) using an ion-beamassisted laser evaporation method. Smooth, dense, environmentally stable coatings with bulk refractive indices were produced. This technique was applied to deposit mid-wave IR dichroic filters using CaF2and Ge layers onto cold substrates.
Effect of Stress on field Confinement in Channel Waveguides formed by Defining Si3N4 Ridges on GaALAS Multilayer Structures
Authors: Radens Carl J. , Roughani Bahram , Jackson Howard E. , Boyd Joseph T. , Burnham Robert D. 
Published: March 2011

ABSTRACTOptical channel waveguiding has been observed in a structure consisting of a silicon nitride ridge on a multilayer GaAlAs heterostructure. The silicon nitride layer was deposited and then patterned to form 3.5 micron wide ridges. The optical field intensity radiating from the endface of the channel waveguide is found to have two peaks symmetric about the center of the silicon nitride ridge. Raman microprobe spectroscopy indicates a significant stress-induced shift in the GaAs longitudinal phonon frequency. Rapid thermal annealing reduces the stress and changes the optical field intensity distribution to a single symmetric peak.
New Non-Oxide Glasses for Optical Waveguiding
Authors: Lucas Jacques 
Published: March 2011

ABSTRACTThe first generation of infrared optical waveguides operating in the mid I.R. region 0.3 to 4 μm is made from fluoride glasses based on zirconium tetrafluoride. A new family of vitreous materials based on indium fluoride appears to be also promising candidate. The state of art in the field including performances and limitations of these optical fibers will be described. A new class of heavy halide glasses based on tellurium chloride, bromide or iodide is presented in relation with their large optical transmission range covering the 8–12 μm region. First attempts in fiber preparation and planar waveguides deposition will be discussed and compared with the traditional chalcogenide glasses.
The Growth of Organic Single Crystals in Glass Capillaries for Second Harmonic Generation
Authors: Holdcroft Geoffrey E. , Dunn P. L. , Rush J. D. 
Published: March 2011

ABSTRACTThe growth and characterisation of a number of organic single crystals, e.g. benzil, 2–methyl–4– nitroaniline and 2–N,N–dimethylamino–5–nitroacetanilide, in silica capillary has become fairly well established over recent years. [1–6 ] However the growth of these same compounds in glass capillary with a much higher refractive index than silica has received little interest. Crystal cored fibres, ccf's, in which there is a close match of the refractive index of the cladding to that of the core allows the possibility of fabricating single mode waveguides with useful dimensions for crystal growth. There is a better overlap integral between phase matched fundamental and second harmonic modes in a low moded structure than in a structure with more allowable modes and thus a rise in the conversion efficiency can be expected if the correct dimensions of waveguide are chosen. If a ccf of high conversion efficiency, 10% at 0.1 mW average power, could be made then the promise of fabricating an organic optical nonlinear device, e.g. parametric amplifier, might be realised. In this paper we will describe how the growth method adopted for silica clad organic crystals has been adapted for their growth in a range of Schott glasses which are better matched in refractive index, RI, than silica to the organic material. The linear and nonlinear optical properties of these crystal cored fibres will be given in terms of; the orientation of the crystal axes with respect to the fibre direction; the sideways scattering characteristics from defects; the throughput of the fundamental beam; the polarisation states of both the fundamental and the second harmonic outputs; and the overall efficiency of second harmonic generation.
On the Structure of Carbon Films Deposited on Si(111) by Mass-Selected Low Energy C+ Beams
Authors: Robertson J. L. , Jiang X. G. , Chow P. C. , Moss S. C. , Lifshitz Y. , Kasi S. R. , Rabalais J. W. , Adar F. 
Published: March 2011

ABSTRACTOur recent report of epitaxial single crystal growth of C+ ion-beam-deposited diamond films on (111) single crystals of silicon is shown to be incorrect. We briefly describe the circumstances leading to this revision (and to our earlier finding) and discuss the possible structure of these films based on preliminary synchrotron X-ray data and on the Raman spectrum.
Defects in KTiOPO4
Authors: Morris P. A. , Crawford M. K. , Ferretti A. , French R. H. , Roelofs M. G. , Bierlein J. D. , Brown J. B. , Loiacono G. M. , Gashurov G. 
Published: March 2011

ABSTRACTKTiOPO4(KTP) is a nonlinear optical crystal presently used for second harmonic generation and electro-optic applications. The properties (ionic conductivity and damage susceptibility) of KTP crystals can vary depending on the specific technique and conditions used for growth. Consistent defect mechanisms have been determined to explain the observed AC conductivity and damage results of KTP grown by the flux and high and low temperature hydrothermal techniques. The presence of nonstoichiometry on the K and O sublattices in KTP, increasing in magnitude with temperature, is proposed. Using these defect mechanisms, the predominant defects compensating for the formation of vacant potassium sites (VK's) in flux and hydrothermal materials are vacant oxygen sites (VO's) and OH−'s, respectively. The presence of a more varied distribution of OH−sites at room temperature in high temperature hydrothermal material with higher AC conductivity indicates the importance of specific OH−sites in the lattice that may enhance the mobility of ionic carriers. The correlation of higher AC conductivity to increased average current and damage in electric field treated KTP is explained on the basis of the proposed compensating defects (VO's and OH−'s) which set the [VK] and [Ti3+]. The similarity of the linear optical properties of KTP grown by the various techniques is confirmed by the insensitivity of the absorption edge to the nonstoichiometry or defects present.
Laser-Induced Formation of Thin Silicone Layers with High Purity
Authors: Roth W. , Henkel H.-J. , Hoffmann K.W. , Markert H. 
Published: March 2011

AbstractUnsaturated and saturated oligomeric siloxanes were polymerized by laser irradiation in the UV range without the use of photoinitiators. The obtained silicon layers possess high purity and non-corrosive effects.
Spin-On Dielectrics: Good News and Bad News!
Authors: Smolinsky G. , Lifshitz N. , Ryan V. 
Published: March 2011

AbstractFive classes of spin-on dielectrics are discussed: polysilicates, polysiloxanes, polysilsesquioxanes, polyhydrocarbons, and polyimides. The emphasis is on the first three materials because very few polyhydrocarbon spin-on materials are available for study while spin-on polyimides sorb significant amounts of water. The polymer chemistry of the silicates, siloxanes, and silsesquioxanes is linkage through Si-O-Si-O bonds. Polyhydrocarbons are primarily linked through C-C bonds. As the name implies, polyimides are linked through (usually aromatic) imide groups. Because of their polar nature, polyimides, polysilicates, and polysiloxanes have dielectric constants >3, while the large hydrocarbon content of the remaining materials results in a dielectric constant of <3. Films of polysilicates are relatively brittle and thus are limited to a thickness <1 μm. On the other hand, films of polysilsesquioxanes, polyimides, and polyhydrocarbons can be readily deposited to a thickness >1 μm. Polysilicates have high temperature (>900°C) stability and do not react with O2; most polyhydrocarbons decompose above ˜350°C and oxidize readily; some polyimides are stable to 500°C; polysiloxanes and polysilsesquioxanes readily survive 425°C in N2. (Films of the latter two materials are converted to silicates upon heating at high temperatures in O2 or steam.) The infrared spectrum of a 425°C-cured silicate film shows the presense of Si-OH bonds and water, but after a 900°C anneal, the spectrum is almost identical to that of thermal oxide. The spectra of films of polysiloxanes or polysilsesquioxanes do not exhibit Si-OH absorption. Water retention in films is deleterious to the electrical and mechanical (swelling) properties of the dielectric and to making good aluminum-to-aluminum electrical contact through submicron vias. The water leads to a mobile charge (H+) phenomenon that is readily detected by a Triangular Voltage Sweep technique. Except for polysilicates, solutions of the other spin-on materials have reasonably long (weeks-to-months) shelf-lives. Polysilicate solutions are sols and tend to gel; the time to gelling is a function of solids content and solvent. Even though they exhibit shortcomings, polysiloxanes appear to be best suited as interlevel dielectrics in multilevel metalization schemes.
Development of New Ion Beam Modification Techniques to Enhance Copper and Polyimide (PI) Adhesion in Multilevel Electronic Packaging.
Authors: Paik Kyung W. , Ruoff Arthur L. 
Published: March 2011

AbstractTwo kinds of ion beam etching techniques, Ar gas ion beam etching (IBE) and oxygen gas reactive ion beam etching (RIBE), were used for adhesion enhancement of the PI/Cu and Cu/PI interface, respectively.Ar gas IBE on Cu followed by deposition of PI film on the modified Cu surface can double the adhesion strength of spin-coated PI on Cu compared with unmodified Cu. The adhesion enhancement is due to increasing the surface contact area of the rough Cu surface to PI. However, a corrosion reaction happens at the polyamic acid (PAA) and Cu interface, resulting in the dissolution of Cu into the PI film and Cu oxide layer growth during curing of PI film. A Cr layer between Cu and spin-coated polyamic acid(PAA) is necessary to keep the Cu from dissolving in PAA and diffusing into PI. Ar IBE modification on Cu followed by deposition of a thin Cr layer on the modified Cu surface is recommended to enhance the adhesion strength of spin-coated PI on Cr.O2 RIBE on PI followed by evaporation of Cu on a modified PI increases the peel strength of Cu/PI by more than 25 times. The maximum peel strength of Cu on the PI modified by O2 RIBE is almost 70 grams/mm. The increase of adhesion is due to the mechanical interlocking of a unique structure of modified PI - a grass-like structure. This structure occurs because of the inhomogeniety of PI film - the presence of ordered and disordered phases in a PI film. In addition, the Cu/PI interface exhibits stability with thermal cycling and humidity, because the adhesion enhancement is mostly due to a mechanical effect and not a chemical effect. The diffusion of Cu into PI at various temperatures is not significant. Typically, Cu atoms can diffuse up to 300 at 400 °C in 1 hour. Another advantage of O2 RIBE on PI is the capability of enhancing the adhesion of the second PI layer on a first PI layer.These technologies allow the precise control of the adhesion strength of the PI/Cr/Cu and Cu/PI interfaces by independent variation of the beam energies, ion doses and angle of beam incidence. Also the ion source is easily installed in the same vacuum chamber for Cr and Cu evaporation. This provides low cost and simple operation.
In SituFTIR Investigations Of Polymer Surface Modification In Downstream Microwave Plasma Etching
Authors: Leu Jihperng , Jensen K.F. 
Published: March 2011

AbstractIn situFourier transform infrared (FTIR) reflection-absorption spectroscopy investigations of etching of thin polyimide and poly(methyl methacrylate) films (200–1500Å) in downstream microwave NF3/O2/Ar plasmas are reported. Etch rates and surface chemistry are monitored as a function of gas phase composition, plasma treatment conditions and time. NF3/Ar plasma treatment leads to significant surface fluorination characterized by the formation of aliphatic fluorine compounds (CFx), acyl fluorides, benzoyl fluoride, and polyfluorinated benzene. Addition of oxygen to the etching gas reduces the degree of surface fluorination and modifies the chemical structure. The absorption bands due to CFxstructures decrease gradually while polyfluorinated benzene rings and benzoyl fluoride are absent for NF3/O2mixtures with more than 20% oxygen. The effect of humidity on the plasma-modified polymers is studied by comparing infrared spectra collectedin situwith those after air exposure. For NF3/O2plasma-treated polyimides significant changes are observed while samples fluorinated in NF3show no changes after exposure to air overnight. The FTIR data are supplemented by XPS analysis.
Morphology of Lignin-Polyurethane Blends
Authors: FeldMan D. , Lacasse N. A. 
Published: March 2011

AbstractThe morphology of blended polyurethane (PU) sealants was studied by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The PU was modifided by mechanical mixing with various amounts of Lignin (L) to achieve a homogeneous blend. Specimens were subjected to control (C), accelerated weathering (AW), and natural weathering (NW) conditions. Results obtained from SEM analysis reveal an even distribution of L particles in the PU matrix. Furthermore, the SEM photomicrographs clearly emphasize the differing morphologies of the constituent phases. They also depict the differences in surface texture between control and aged specimens. The DSC analysis shows that the two phases are immiscible which is in agreement with observations by microscopy.
Film Stress in High Density Thin Film Interconnect
Authors: Pan J. Tony , Poon Steve 
Published: March 2011

AbstractHigh density thin film interconnects are expected to be widely used for multi-chip module application to accommodate next generation high I/O and high speed integrated circuits. These interconnects typically use polyimide as the dielectric, and aluminum or copper (with protective overcoat) as the conductor. The interconnects are typically built on silicon or alumina substrates. Large film stress occurs due to the high processing temperature required to cure polyimide and due to the mismatch in thermal coefficients of expansion (TCE) between the film materials and substrate materials. This work studies film stress for these materials.An instrument which measures thin film stress in-situ at temperatures between 25 and 450°C was used to characterize the stress in polyimide, nickel, and copper films. Two substrate materials, silicon and sapphire, were used in order to extract the TCE and elastic modulus for each film material. Three polyimide materials were evaluated. One of the polyimides studied showed complete stress relaxation at temperatures above 300°C and was almost completely elastic upon heating and cooling between 25 and 300°C. The TCE was calculated to be 41×10−6/°C and the biaxial elastic modulus was 4.0×109 Pascal. The nickel had very low stress asplated, however, high tensile stress was observed after 350°C annealing as a result of TCE mismatch. After first annealing, the nickel was almost completely elastic upon cooling and repeated heating and cooling between 25 and 350°C. Copper, on the other hand, was not completely elastic under similar thermal treatments. High thermal stress caused plastic deformation to occur in copper films. The room temperature stress in copper film after 350°C annealing depended on yield strength instead of TCE mismatch. The stress in these materials and its effects on processing and reliability for high density interconnect will be reported.
Adhesion of Copper to Polytetrafluoroethylene
Authors: Kim Yong-Kil , Chang Chin-An , Schrott A. G. , Andreshak J. , Cali M. 
Published: March 2011

AbstractAn enhancement of the adhesion between copper and polytetrafluoroethylene (PTFE) has been studied. Thin-films of copper were electron-beam deposited on the surface of the polymer substrates. Peel test measurements showed that, without any treatment of the substrates, the adhesion was poor with a peel strength of 1–2 g/mm. A pronounced enhancement of the adhesion has been obtained when the fluorocarbon substrates were treated by either an ultraviolet (UV) irradiation, an ion-beam presputtering prior to the metal deposition, or heat treatments after the deposition. Among the treatments employed, the ion-beam sputtering was the most effective in improving the adhesion. The roles of the treatments and possible reasons for the enhanced adhesion are discussed in conjunction with the studies of interface morphology and chemistry using Scanning Electron Microscopy, Rutherford Backscattering Spectroscopy, and X-ray Photoelectron Spectroscopy.
The Aspects of Thermal Anneal to Intrinsic Stress and Microstructiire of Multilayer Thin Films
Authors: Yang C. H. , Chen P.C. 
Published: March 2011

AbstractAdhesion degradation mechanism at the interface of a multilayer thin film was studied as a function of annealing temperature. The multilayer thin films employed for current investigation of the temperature effect were constructed by sputtering 500 Å Cr and 10K Å Cu on both sides of kapton. A steady decrease of adhesion strength was found as a result of increasing the annealing temperature from 150°C to 350°C. Thin film and interfacial properties in association with degradation of adhesion were characterized by several techniques, including intrinsic stress measurement, Auger, TEM and SIMS. Siveral changes were observed by elevating the annealing temperature. It was found that the intrinsic stress in each layer changed. Both Cu and Cr grain size increased with the annealing temperature. The interface at kapton and metal became more defined. The Cu atoms were found to become mobile and diffused into Cr and kapton layer after a 350 degree annealing. In addition, a change of molecular orientation and chemistry in kapton near the interface was observed by SIMS and XPS studies. A combination of these factors resulted in a decline of adhesion strength.
XPS Study of Polyimide H-Film After Heat Treatment and Laser Processing
Authors: Nagarkar P.V. , Sichela E.K. , Doll G.L. 
Published: March 2011

AbstractAn x-ray photoelectron spectroscopy (XPS) study of laser treated and heat treated Kapton®indicates that both the treatments result in depleting the carbonyl groups from the sample and leave behind a conducting residue that still contains significant amounts of oxygen and nitrogen. The rapid changes in surface composition coincide with a substantial decrease in the electrical resistivity of the polyimide samples.
Dielectric, Conducting, and Photonic Polymers for Devices in Multichip Packaging
Authors: Mcdonald John F. , Vlannes Nickolas P. , Wnek Gary E. , Lu Toh-Ming 
Published: March 2011

AbstractPolymeric materials have traditionally enjoyed widespread use in the electronics industry. Recent advances in the identification and synthesis of polymers with unusual electrical and optical properties have opened new opportunities for technological applications. Some of these novel properties are summarized in this paper with an emphasis on how these properties may be usefully exploited in the area of multichip packaging.
Materials Problems Affecting Reliability and Yield of Wire Bonding in VLSI Devices
Authors: Harman George G. , Wilson Charles L. 
Published: March 2011

AbstractMaterials problems have always been a significant cause of wire bond failures in microelectronics. However, modern VLSI materials, processing, and packaging methods combined often result in new or masked versions of old failure mechanisms. This paper describes the classical Au-Al intermetallic compound problem as described by a new two-dimensional finite element diffusion model and demonstrates that diffusion in poor welds is more rapid than in bulk couples. Failures resulting from modern bonding material couples (e.g., Cu-Au, Al-Ag, etc.) can result in bond failures superficially resembling Au-Al type failures. Failures resulting from bonds made to contaminated gold electroplated films are described, and a new failure model resulting from hydrogen in these films is shown.