bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surface-Controlled Reactivity of Metal Carbonates
Authors: Brady P. V. 
Published: April 2011

AbstractMetal carbonate surfaces are a common component of soils, sediments, terrestrial organisms, and many engineered structures. The surface-controlled growth and dissolution of metal carbonate minerals (e.g. calcite) often affects fluid flow in pipes (through scaling) as well as the nanoscale assembly of complex biologic structures (similar reactions control Ca levels in the oceans, and ultimately, long-term CO2 levels). Engineering metal carbonate surface chemistry to enhance or inhibit growth, dissolution, or crystal nucleation is therefore an area with obvious economic impact. Metal carbonate superstructures are rapidly altered by dissolution/re-precipitation reactions, necessitating the measurement of surface chemistry near equilibrium. Measurements of metal sorption using limited residence time reactors point to the importance of adsorbed/exchanged metal ions in controlling surface charge and electrokinetic behavior. The same reactions appear to control growth and dissolution rates as well.
The Effect of the Adsorption of Metal Ions on the Interfacial Behavior of Silicate Minerals
Authors: Huang Picheng , Fuerstenau Douglas W. 
Published: April 2011

AbstractBecause of its importance in the fields of environmental and mineral engineering, the adsorption mechanism of metal ions on oxides has been studied rather extensively using such techniques as titration, adsorption isotherm determination, flotation and spectroscopy. However, limited work has been done to compare the behavior of hydrophilic silicates with those that are naturally hydrophobic. Our investigation was undertaken to provide a better understanding of the adsorption mechanism of selected metal ions at the solid/liquid interface through simultaneous measurements of zeta potentials, adsorption densities and turbidity on colloidal suspensions of two silicate minerals, quartz and talc, as a function of pH, to delineate the effect of hydrophobicity and surface heterogeniety on these processes.
Fabrication of YMnO3 Films: New Candidate for Non-Volatile Memory Devices
Authors: Fujimura Norifumi , Ishida Tadashi , Yoshimura Takeshi , Ito Taichiro 
Published: April 2011

AbstractWe have proposed ReMnO3 (Re:rare earth) thin films, as a new candidate for nonvolatile memory devices. In this paper, we try to fabricate (0001) oriented YMnO3 films on (111)MgO, (0001)ZnO:Al/(0001) sapphire and (111)Pt/(111)MgO using rf magnetron sputtering. We succeed in obtaining (0001) epitaxial YMnO3 films on (111) MgO and (0001)ZnO:Al/(0001)sapphire substrate, and polycrystalline films on (111)Pt/(1 11)MgO for the first time. Electrical property of the bottom electrode (ZnO:Al) changes with varying the deposition condition of YMnO3 films. However, we find an optimum deposition condition of ZnO:Al film such that it functions as a bottom electrode even after YMnO3 film deposition. The dielectric properties of the epitaxial and polycrystalline YMnO3 films are almost the same. The YMnO3 films show leaky electrical properties. This may be caused by a change in the valence electron of Mn from 3+.
Microstructure Control in Mocvd PZT Thin Films
Authors: Kim Daesig , Kim Tae-Young , Lee June Key , Tao W. , Desu Seshu B. 
Published: April 2011

AbstractIt was shown that Pb(ZrxTi1−x)O3 thin films (PZT) can be successfully deposited by metalorganic chemical vapor deposition (MOCVD) in a wide deposition temperature range starting from 400°C to 600°C. Variations in texture, morphology and grain size of the films as a function of process parameters were systematically investigated by x-ray diffraction (XRD) and scanning electron microscopy (SEM). The deposition temperature and gas composition in the reactor are the two key parameters that control the film microstructure. The accompanying changes in the ferroelectric properties with respect to the variations of the process parameters will also investigated. In addition, we found an interrelationship between the grain orientation and surface roughness of the films. Films with (111) preferred orientation are significantly smoother than the films with other preferred orientations. We also demonstrate, for the first time, fine grained PZT films with very low surface roughness, which show excellent electrical properties can be obtained by lowering the deposition temperature (e.g. 430°C)
Analysis of Pulsed Excimer Laser Ablation of PZT, Pb And Ti in an Oxygen Ambient Using Energy Dispersive Mass Spectrometry
Authors: Coccia L. G. , Tyrrell G. C. , Boyd I. W. 
Published: April 2011

AbstractA number of factors have been identified as affecting the gas phase oxidation of cations during pulsed laser ablation of lead zirconate titanate (PZT), by using energy dispersive mass spectrometry (EDMS). These phenomena are known to be critical to the deposition of high quality thin films of PZT. However, to isolate the role of each cation species and the influence of its gas phase properties, we have also looked beyond the ablation of the PZT ceramic. In this paper, we detail our observations during pulsed laser ablation of electroceramic and metallic targets, specifically PZT, Pb and Ti. We have observed the evolution and transport of molecular species during gas phase expansion over a wide range of oxygen pressures (10−7 - 10−1 mbar) and laser fluences (0.3 -10 Jcm−2). The yields of the molecular ion species are strongly dependent upon the number density of the background gas. We propose an interpretation of the relative yields of the species based upon their respective gas phase binding energies and their ease of formation based upon the reaction thermodynamics and reaction cross-section of each species.
Integrated Decoupling Capacitors using Pb(Zr,Ti)O3 Thin Films
Authors: Dimos D. , Lockwood S.J. , Garino T.J. , Al-Shareef H.N. , Schwartz R.W. 
Published: April 2011

AbstractThin-film decoupling capacitors based on ferroelectric (Pb,La)(Zr,Ti)O3 films are being developed for use in advanced packaging applications. The increased integration that can be achieved by replacing surface-mount capacitors should lead to decreased package volume and improved high-speed performance. For this application, chemical solution deposition is an appropriate fabrication technique since it is a low-cost, high-throughput process. The use of relatively thick Pt electrodes (˜1 μm) to minimize series resistance and inductance is a unique aspect to fabricating these devices. In addition, the important electrical properties are discussed, with particular emphasis on lifetime measurements, which suggest that resistance degradation will not be a severe limitation on device performance. Finally, some of the work being done to develop methods of integrating these thin-film capacitors with ICs and MCMs is presented.
Piezoelectric Characterization of Bulk and Thin Film Ferroelectric Materials using Fiber Optics
Authors: Dawley J.T. , Teowee G. , Zelinski B.J.J. , Uhlmann D.R. 
Published: April 2011

AbstractIn this study, the use of a fiber optic technique for the measurement of the piezoelectric properties of ferroelectric bulk and thin film samples was investigated. The strain and piezoelectric properties (namely the d33 coefficients) were measured using the MTI-2000 Fotonic Sensor, which uses the principle of the optical lever to resolve very small changes in sample displacement (1 Å). Using this technique, we were able to detect the very small strains associated with the converse piezoelectric effect for PVDF films and bulk PZT samples, and correlate the results with data acquired from direct piezoelectric effect measurement. Comparison of the data sets prove that the optical lever would be a useful optical technique for measuring of the d33 values of ceramic thin films, such as BaTiO3, ZnO, and PZT.
Processing and Piezoelectric Properties of Mod Pzt Films and Pzt/Polymer Composite Coatings
Authors: Wright J.S. , Francis L.F. 
Published: April 2011

AbstractLead zirconate titanate, Pb(Zr0.53Ti0.47)O3 (PZT), coatings were prepared using a metallorganic decomposition (MOD) route with lead and titanium acetates and zirconium acetylacetonate in acetic acid and water. Films with thickness of 0.66 μm were prepared on (100) Si with a layered bottom electrode (Pt/Ti/TiO2/SiO2). Dielectric constant and loss were 1100 and 0.04 (1 kHz), respectively, and remnant polarization and coercive field were 30 μC/cm2 and 40 kV/cm. Piezoelectric coefficient (d33) of the PZT film, measured with a singlebeam laser interferometer, was 41 pm/V. Standard micromachining techniques were used to etch the PZT to form discrete PZT posts for preparation of the ceramic phase for composite coatings with a 1–3 connectivity. SEM was used to determine the dense and etched film microstructure. Preliminary ion milling results, used to etch the PZT, are also presented.
Size Effects and Domains in Ferroelectric Thin Film Actuators
Authors: Trolier-Mckinstry S. , Randall C. A. , Maria J. P. , Theis C. , Schlom D. G. , Shepard J. , Yamakawa K. 
Published: April 2011

AbstractFerroelectric thin films typically differ from bulk ceramics in terms of both the average grain size and the degree of stress imposed on the film by the substrate. Studies on bulk ceramics have demonstrated that the number of domain variants within grains depends on the grain size for sizes <˜lμm. This can diminish the poling efficiency of the material. Since most thin films show primary grain sizes well below a micron, similar effects should be observed in films. In addition, since the perovskite ferroelectrics contain ferroelastic as well as ferroelectric domains, it seems clear that stress in thin films may markedly alter the degree to which domain walls contribute to the observed properties. In this paper, the relative importance of these factors are discussed for several types of ferroelectric thin films. Films have been prepared by pulsed laser deposition, magnetron sputtering, and by sol-gel processing. It has been found that epitaxial BaTiO3 films are ferroelectric at 77K down to thicknesses as low as ˜ 60nm. Data on the low and high field electrical properties are reported as a function of temperature, the film crystallinity, and film thickness for representative perovskite films.
SrBi2Ta2O9 Capacitors for a Mega-Bit Ferroelectric Nonvolatile Memory
Authors: Amanuma Kazushi , Kunio Takemitsu , Cuchiaro Joe 
Published: April 2011

AbstractSrBi2Ta2O9(SBT) capacitors were integrated to the structure for a mega-bit nonvolatile memory, and their electrical properties after metallization were investigated. Annealing above 500°C after contact-etching was necessary to obtain good electrical properties. A well saturated hysteresis loop with 2Pr of more than 15μC/cm2 was obtained for the 0.7×0.7μm capacitor. The read-out polarization was very stable in 105 sec after the write-pulse. No fatigue or imprint was observed up to 1011 cycles. These results show suitability of SBT capacitors for a mega-bit non-volatile memory.
Integration Aspects and Electrical Properties of SrBi2Ta2O9 for Non-Volatile Memory Applications
Authors: Taylor D.J. , Jones R.E. , Lii Y.T. , Zurcher P. , Chu P.Y. , Gillespie S.J. 
Published: April 2011

AbstractHighlights and solutions to some of the challenges involved in integrating SrBi2Ta2O9 (SBT) capacitors with Pt electrodes on silicon wafers for non-volatile memory applications are discussed. These include the diffusion of Bi through the Pt bottom electrode during firing, capacitor patterning, and process damage that results from hydrogen containing atmospheres.Next, studies of the temperature dependence of many of the important electrical properties of SBT are presented. These include the remanent polarization (2Pr), the non-volatile polarization (Pnv), and the coercive field (Ec) all of which are studied as functions of the pulse amplitude; fatigue resistance of 2Pr and Pnv; the retention; the small signal capacitance versus voltage behavior; and the current versus voltage behavior. These studies demonstrate that SBT looks very promising for ferroelectric non-volatile memories over the consumer application range (0 to 70 °C).
Dislocation Nucleation and Multiplication During Nanoindentation Testing
Authors: Mann A. B. , Pethica J. B. 
Published: April 2011

AbstractSmall volumes of crystalline material can exhibit near theoretical lattice strengths due to the absence of pre-existing defects. We show here that careful control of experimental parameters and surface preparation are important in observing these increased stresses. In particular, tip impact kinetic energies at the initial contact of only a few eV have been found to influence events occurring at a much later stage in the loading cycle. This can be understood in terms of the energy required to deform a small number of atomic scale asperities and thus release sufficient surface energy to permit dislocation nucleation at impact. If the K.E. is not sufficient to overcome the asperities, dislocations must be nucleated at a later stage in the loading cycle, giving a apparently different mechanical property. We outline the implications for thin film systems where a hard surface layer may play a vital role, firstly, in preventing dislocation nucleation on impact and, secondly, in impeding the propagation of any such dislocations into the bulk below.
Hard Amorphous Hydrogenated Carbon Films Deposited from an Expanding Thermal Plasma
Authors: Gielen J. W. A. M. , Sanden M. C. M. Van De , Kessels W. M. M. , Schram D. C. 
Published: April 2011

AbstractDiamondlike amorphous hydrogenated carbon is deposited from an expanding thermal argon/acetylene plasma. It is observed that the film quality improves with increasing deposition rate. To obtain the best material quality the admixed acetylene flow has to be of comparable magnitude as the argon ion flow from the plasma source (critical loading). A new method to determine the ion density in an argon/acetylene plasma, by probe measurements, is presented. They reveal that the deposition during critical loading is governed by radicals. It is suggested that acetylene is dissociated once and that the C2H radical is formed dominantly.
Microhardness Study Of Cathode-Mounted Amorphous Hydrogenated Boron Carbide
Authors: Lin Shu-Han , Li Dong , Feldman Bernard J. 
Published: April 2011

AbstractWe have grown cathode-mounted amorphous hydrogenated boron carbide thin films by rf plasma decomposition of diborane and methane. The chemical composition, infrared absorption, optical absorption, microhardness and adhesion of these thin films were measured. As a function of increasing diborane concentration in the feedstock, we observe increasing boron and decreasing hydrogen concentrations, increasing infrared absorption at 1300 cm-1 due to boron icosahedra, increasing optical band gaps, dramatically increased microhardness, and increased adhesion to the underlying substrates of these thin films. These results provide evidence that the presence of boron icosahedra increases microhardness, adhesion, and optical band gaps.
The Effect of the Passivation Material on the Stress and Stress Relaxation Behavior of Narrow Al-Si-Cu Lines
Authors: Witvrouw A. , Flinn P. , Maex K. 
Published: April 2011

Abstract800 nm thick and 1μm wide Al-1wt.%Si-0.5wt.% Cu parallel lines with 1 μm spacing were passivated with PECVD oxide, oxynitride or nitride. Substrate curvature measurements as a function of temperature and XRD-measurements at room temperature were used to characterize macroscopic samples of these parallel Al-Si-Cu-lines. By using both techniques the average inplane stresses for the Al-Si-Cu lines as well as for the covering passivation material can be determined as a function of temperature. The highest and lowest stresses in the Al-Si-Cu are observed for lines with nitride and oxide passivations, respectively. Also the number of voids in the lines after a storage test at 250 °C is clearly highest for a nitride passivation and lowest for an oxide passivation.The stress in the passivation itself and its temperature dependence is found to be very different from the stress in a blanket passivation film.
Morphological Instability of a Sic Film During Carbonization
Authors: Chiu C.-H. , Freund L. B. 
Published: April 2011

AbstractA model is developed to understand the morphological stability of a SiC film on a Si substrate during carbonization where the Si substrate is exposed to a carbon precursor. The morphological stability is determined by considering the surface evolution along a slightly wavy film surface and film-substrate interface. The morphological evolution along the film surface is dominated by surface diffusion and along the interface by a chemical reaction. The kinetic analysis shows the stability is controlled by the film surface energy, the interface energy, the diffusion-reaction process of the carbon precursor, and the strain energy. At small wavelengths of the surface profiles, the two types of surface energy dominate, which results in stable morphology. The diffusion-reaction process dictates the surface stability at large wavelengths. The strain energy may cause the surfaces to become unstable at moderate wavelengths; the instability can be completely suppressed by the diffusion-reaction process and the film surface energy, while it is enhanced by a large value of interface energy.
Plastic Deformation in Thin Copper Films Determined by X-Ray Micro-Tensile Tests
Authors: Kretschmann A. , Kuschke W.-M. , Baker S. P. , Arzt E. 
Published: April 2011

AbstractPlastic deformation in thin copper films has been studied at room temperature. Copper films having a thickness of 1 μm were made by sputtering onto nickel substrates with a Si3N4 underlayer and with or without a Si3N4 caplayer. Deformation experiments were conducted using a special micro-tensile tester built into a θ–θ diffractometer. The problems normally associated with tension tests of free-standing films were avoided by deforming the substrate and film together. In-situ x-ray measurements of the lattice spacings and lattice spacing distributions were used to determine both elastic and plastic strains. The effects of caplayer and annealing temperature on mechanical properties are reported.
Structural Transformations During Growth of Epitaxial Fe(001) Thin Films on Cu(001) and Pt(001)
Authors: Clemens B. M. , Hufnagel T. C. , Kautzky M. C. , Bobo J.-F. 
Published: April 2011

AbstractWe have used grazing incidence x-ray diffraction to observe the structural evolution during growth of sputter-deposited epitaxial Fe films on Cu(001) and Pt(001). We find that on Cu(001), Fe is fcc up to a thickness of 10–12 monolayers, whereupon bcc Fe is observed in first the Pitsch and then the Bain orientations. The fcc Fe shows some relaxation of the misfit from the Cu, as do the Pitsch orientation bcc, which is in tension, and the Bain orientation bcc, which is in compression. All three Fe variants exist in a 40 monolayer thick film. On Pt(001) the Fe grows as bcc with the Bain orientation. However, a thin (20 å) bcc Fe film is transformed to fcc Fe with cube-on-cube orientation by subsequent deposition of Pt. This behavior is consistent with intermixing of Pt into the Fe layer, which lowers the mismatch and bulk chemical energies of the fcc phase relative to that of the bcc phase.
Dynamic In-Situ Synchrotron X-Ray Topographic Observations Of Dislocations In Notched Ice Crystals
Authors: Hu X. , Baker I. , Dudley M. 
Published: April 2011

AbstractExperimental observations of ice single crystals strained under uniaxial tension using synchrotron X-ray topography have shown that there is far more dislocation activity around notches at high temperature, -7.8°C, than at lower temperatures (-40°C and -60°C).
Static Atomic Displacements in Crystalline Solid Solution Alloys
Authors: Ice Gene , Sparks Cullie , Robertson J. Lee , Epperson J. Ernest , Jiang Xiaogang 
Published: April 2011

AbstractAtom size differences induce static displacements from an average alloy lattice and play an important role in controlling alloy phase stability and properties. The details of this role however, are difficult to study; chemical order and displacements are strongly interrelated and static displacements are hard to measure. Diffuse x-ray scattering measurements with tunable-synchrotron radiation can now measure element-specific static displacements with an accuracy of ± 0.1 pm and can simultaneously measure local chemical order out to 20 shells or more. Ideal alloys for diffuse scattering analysis with synchrotron radiation, are those that have previously been the most intractable: alloys with small Z contrast, alloys with only local order and alloys with small size differences. The combination of precise characterization of local chemical order and precise measurement of static displacement provides new information that challenges existing alloy models. We report on an ongoing systematic study of static displacements in the Fe/Ni/Cr alloys and compare the observed static displacements to the static displacements predicted by current theories. The availability of more brilliant 3rd generation hard x-ray sources will greatly enhance these measurements.
X-Ray Absorption Analysis of Electroplated Permalloys Used in Microfabrication
Authors: MOLDERS N. , SCHILLING P. J. , He J.-H. , Saile V. , Moser H. O. , Menz W. 
Published: April 2011

AbstractElectroplating is a key technology in the LIGA process (German acronym for Lithographie (Lithography), Galvano (Electroplating) and Abformung (Moulding)). The electroplating process determines the physical, chemical, and mechanical properties of a device. In the macro environment, the process is empirically understood arid electroplating results are fairly well predictable. For use in the micro environment, in particular in microfabrication of LIGA components with high-aspect-ratios, effects like delamination from the substrate, inhomogeneous material distribution, pores in the material and large grain sizes have to be avoided. It is, therefore, important to investigate the structure and composition of such materials. Various electroplated Permalloy foils have been prepared, which are of interest because of their soft magnetic behaviour and use as materials for microsensors and microactuators. X-ray absorption fine structure (XAFS) and x-ray absorption near edge structure (XANES) have been recorded at the Nickel and Iron K-edges (8333 and 7112 eV respectively) for electroplated Permalloy.
Investigations on Fe Lattice Strain Relaxation in the Al/Fe/Al Trilayer
Authors: Mayanovic Robert A. , Gutierrez Carlos J. , Prinz Gary A. 
Published: April 2011

AbstractWe have measured polarization-dependent Fe K-edge XAFS spectra from an epitaxially-grown Al/Fe/Al/ZnSe/GaAs(001) sample using synchrotron radiation. The Fourier-transformed XAFS spectra were fit up to four coordination shells simultaneously using theoretical spectra generated with FEFF 6. Our results reveal a small tetragonal distortion of the bcc α-Fe film lattice towards a contraction in the film growth direction (c=2.863 Å and a=2.874 Å; bulk a=2.867 Å). The anomalous tetragonal distortion is consistent with a model involving substantial interdifussion of Fe and Al, leading to Fe1−xAlx alloy formation localized in the interface regions.
Grazing Incidence X-Ray Diffraction Study of A Glass-Liquid Crystal Buried Interface
Authors: Martínez Miranda L. J. 
Published: April 2011

AbstractWe have used Grazing Incidence X-ray Diffraction to study the structure of a liquid crystal (LC) at the buried LC-glass interface in micrometer size LC films. This measurement is done in reflection mode through the glass substrate, which consists of a grating photolithographed onto a 0.2mm slide. This experiment was performed in beamline X22B of the National Synchrotron Light Source at Brookhaven National Laboratory, using 1.3776Å X-ray radiation. We have used both the glass and LC absorption properties to control the penetration depth of the beam into the LC film bulk. The ability to measure LC interfaces in this manner is essential to study any LC device, arid its response to applied fields.