bluuebunny/crossref_metadata_2025_split huggingface dataset:
Localized Texture Formation and its Detection in Polycrystalline Thin Films of Gold
Authors: Harris Karen E. , King Alexander H. 
Published: March 2011

ABSTRACTWe have developed a technique for detecting microscopic variations in texture in thin film TEM specimens using conical dark field imaging. This technique has been used to identify texture variations in 25nm thick gold films which were deposited on rock salt and annealed at 150°C. After annealing, the films were Mostly (111) textured with one micrometer wide bands of contrast in which the grain remained randomly oriented. When the contrast due to the variation in texture was first observed, the films were columnar-structured and the grain sizes in both the textured and un-textured regions were uniform, with a mean equivalent diameter of 54nm; no abnormal grains were observed. After additional annealing, abnormal (111) oriented grains appeared in some untextured regions of the film. The evolution of texture during grain growth and the influence of substrate morphology on texture formation will be discussed.
Strain, Stress, and Magnetic Surfaceanisotropy of Epitaxial FE(110)/MO (110) Multilayers
Authors: Osgood R.M. , Clemens B.M. , White R.L. , Brennan S. 
Published: March 2011

ABSTRACTGrazing incidence and asymmetric X-ray diffraction were used to measure the stress and strain state of Fe(110)/Mo(110) Multilayers. The highest stress in the Fe constituent of the multilayer was along the [110] in-plane direction and was due to interaction with the substrate. The Magnetic anisotropy of the Fe Multilayer constituent was measured and the magnetic surface anisotropy, which favored in-plane [001] magnetization, was deduced. In contrast, the magnetic surface anisotropy of a single layer of Fe on W preferred in-plane [110] magnetization, in agreement with the Néel Model.
Substrate Effects on The Growth of Oriented MgO Thin Films
Authors: Chang Bertha P. , Sonnenberg Neville , Cima Michael J. 
Published: March 2011

ABSTRACTMgO thin films were deposited onto SrTiO3 and LaAlO3 single crystal substrates using off-axis rf-Magnetron sputtering. Films from 1000–3000Å thick were grown in an Ar - 20%O2 atmosphere at temperatures between 200 and 700°C. X-ray measurements indicate MgO grows epitaxially on SrTiO3 at temperatures above 400°C. The Microstructure of these films was smooth and dense. At deposition temperatures below 400°C, orientation is Maintained, but a rough plate-like microstructure begins to take over. MgO films deposited on LaAlO3 grow with a high degree of preferred orientation. Film Microstructure resembled MgO deposited on SrTiO3 at temperatures below 400°C. Variations in the quality of MgO films grown on LaAlO3 were also observed which may be related to variations in steps on the substrate surfaces.
Texture in Sputtered MO Films
Authors: Karpenko O.P. , Vill M. , Malhotra S.G. , Bilello J.C. , Yalisove S.M. 
Published: March 2011

ABSTRACTThe evolution of texture in thin films must be fully understood in order to take advantage of favorable crystallographic orientations in a material for a given application. The development of an out-of-plane texture (preferred crystallographic orientation in the growth direction) and an in-plane texture (preferred crystallographic orientation in the plane of growth) in sputter deposited, thin mo films on Si was studied using transmission electron microscopy and diffraction, and conventional x-ray pole figures. For a range of deposition parameters, a strong (110) out-of-plane texture developed within 1000Å, while a strong in-plane texture did not develop until a thickness of about 1 μm.
Grain Growth in Thin Films With Variable Grain Boundary Energy
Authors: Frost H.J. , Hayashi Y. , Thompson C.V. , Walton D.T. 
Published: March 2011

ABSTRACTIn simulations of grain growth in thin films we have considered the effect of variations in grain boundary energy. Boundary energy depends on both the misorientation between the two neighboring grains, and the angles which the boundary plane makes with the crystallographic axes of the two crystals. Variations in grain boundary energy mean that dihedral angles at triple junctions deviate from 120°. The proportionality between boundary velocities and local curvatures, and the critical curvature for boundary pinning due to surface grooving also both depend on boundary energy. One effect of variable boundary energies is that grains no longer gain or lose area at rates determined solely by their topology or number of sides. (They no longer obey the Von Neumann/Mullins law). Another effect is that as the grain structures evolve, the fraction of high-energy boundaries decreases. Also, the stagnant structures have broader grain size distributions.
On the Evolution of Copper Oxide Films Grown on α-A12O3 By Pulsed-Laser Ablation
Authors: Bench Michael W. , Sartain Kevin B. , Heffelfinger Jason R. , Barry Carter C. 
Published: March 2011

ABSTRACTPulsed-laser ablation was used to deposit copper oxide onto single-crystal substrates of (0001) OC-AI2O3 at temperatures ranging up to 900°C. Prior to deposition, the substrates were chemically cleaned and annealed to create a surface structure of low-index terraces separated by crystallographic steps. After deposition, the samples were characterized using transmission electron microscopy and scanning electron Microscopy.The deposited film evolved by an island growth process, with the morphology of the particles being dependent on the growth conditions, substrate orientation, and nature of the substrate surface. Both CuO and Cu2O were produced by the depositions. The phase observed changed from CuO to Cu2O with increasing deposition temperature, as would be expected based on the equilibrium phase diagram. In depositions performed on (0001) alumina substrates with widely spaced surface steps, it was found that on some surface terraces one characteristic particle morphology was produced whereas on others a second morphology was dominant. This suggests that the plane of surface termination in the alumina lattice, which consists of a layer of either Al or O in this orientation, is influencing the growth process.
Nucleation of Special Orientations During Heteroepitaxial Growth of Diamond on Silicon
Authors: Tzou Y. , Raj R. , Bruley J. , Ernst F. , Riihle M. 
Published: March 2011

ABSTRACTThe orientation relationships that develop in the early stages of diamond nucleation on silicon, were examined by TEM and HRTEM. The films were produced by microwave plasma assisted CVD. Two types of interface regions were identified. In one case an amorphous interlayer was observed and the nucleation of diamond was nanocrystalline. In the second case the interface was apparently free from a second phase; in these instances the diamond and silicon lattices formed special orientations. The special orientations were identified as the following: (a) <110> 60 degree rotation, (b) <110> 90 degree rotation and (c) diamond {111} plane tilted 6 degrees from silicon {220} plane. The orientation relationships are analyzed in terms of geometric models that seek the best fit between the diamond and silicon lattices at the interface plane.
Atomistic Configurations of Diamond/Silicon Interface
Authors: Nandedkar A. S. , Narayan J. 
Published: March 2011

ABSTRACTThe quality of diamond thin films on nondiamond substrates is often poor because of large number of defects such as dislocations, twins, stacking faults and grain boundaries. The diamond films often exhibit poor adhesion on nondiamond substrates because of large differences in interatomic potentials between the film and the substrate. The epitaxial nature of the film is determined not only by lattice matching but also by gradient in interatomic potentials across the interface. We have used computer simulations to study energetics of different geometric configurations of C / Si interfaces. The simulations predict that an C / SiC interface had the least energy and therefore the preferred interface configuration. This is in concordance with experimental deposition of C on Si which resulted in formation of an SiC layer in between C and Si.
Epitaxial Chemically Derived Lanthanum Aluminate Films for Ba2YCu3O7−x Devices
Authors: Faing Man , Cima Michael J. 
Published: March 2011

ABSTRACTLanthanum aluminate (LaAlO3) has been used as a substrate material for depositing Ba2YCu3O7−x (YBCO) films. In the present study, chemically derived epitaxial LaAlO3 thin films were used for depositing epitaxial YBCO films. These epitaxial LaAlO3 films were deposited on both (100) SrTiO3 and (100) LaAlO3 single crystal substrates by pyrolysis of a mixed nitrate precursor. Crystallization of LaAlO3 on lattice-Matched substrates occurs at below 650°C, whereas crystallization on non lattice-Matched substrates occurs at much higher temperature. The average surface roughness of these LaAlO3 films can be as low as 7Å. The YBCO films derived from metalorganic deposition of metal trifluoroacetate precursors were deposited on these epitaxial LaAlO3 films on SrTiO3 substrates. The resultant YBCO films have critical current densities of > 2 × 106 A/cm2 at 77K and zero field. Transmission electron microscopy of these films shows that they are highly epitaxial yet have pore of about 15–30 nm in size. Chemically derived LaAlO3 films also were used to planarize stepped substrates.
Evolution of Yttrium Aluminum Garnet Films by Solid-State Reaction
Authors: Heffelfinger Jason R. , Barry Carter C. 
Published: March 2011

ABSTRACTYttrium aluminum garnet (YAG) films were produced by reacting thin Y2O3 layers with single-crystal Al2O3 substrates. Y2O3 films were deposited using pulsed-laser deposition (PLD), which produced smooth textured films on specially prepared (0001) α-Al2O3 substrates. Solid-state reaction of the Y2O3 with the Al2O3 was induced by specific heat treatments. Transmission-electron microscopy was used to characterize the reaction products of each heat treatment. For a reaction temperature of 1200°C, cross-sectional TEM specimens revealed the development of Monoclinic Y4Al2O9 at the interface between the Y2O3 and the Al2O3. Development of YAG was seen to occur at the interface between the Al2O3 and the Y4Al2O9 for a slightly higher reaction temperature of 1250°C. The Metastable Y4Al2O9 phase and the Y2O3 phase were found to be consumed at higher reaction temperatures to form the equilibrium Y3Al5O12 (YAG) phase. The Morphology of the YAG film was characterized by scanning-electron microscopy.
Interfacial Reaction Between a Sputter Deposited MoSi2 Film and its Oxidation Product on Al2O3 at 1300°C in Air.
Authors: Wu P.K. , Kolaya L.E. , Duquette D.J. , Hudson J.B. 
Published: March 2011

ABSTRACTThe chemical compatibility between MoSi2 and Al2O3 at 1300° C was examined using sputter deposited MoSi2 films, 0.7 μm thick, on sapphire and on polycrystalline alumina. The oxidation behavior of the sputter deposited films was found to be identical to that of bulk MoSi2. The oxidation products of the MoSi2 are Si oxides and lower suicides of Mo. MoO3 is formed and sublimes at the free surface. Oxidation is found to occur at the SiO2/MoSi2 interface. Just beneath this interface, suicides of mo and two oxidation states of Si were identified. No reaction between MoSi2 and alumina was found. In the case of a sapphire substrate, after mo was completely eliminated from the interface, silica reacted with the substrate and eventually phase separated into high- and low-silica phases. Nucleation, growth and coalescence of high-silica precipitates were observed.
Epitaxial Alignment and Microstructural Development in Lithium Niobate Thin Films Prepared by Metallo-Organic Decomposition.
Authors: Braunstein G. , Paz-Pujalt G. R. , Blanton T. N. 
Published: March 2011

ABSTRACTWe investigate the microstructural evolution and epitaxial alignment of thin films of LiNbO3 deposited by the Metallo-organic decomposition method on Al2O3. The LiNbO3 films are prepared by spin coating and thermal decomposition of a solution of Metallo-organic precursors on single-crystal, <0001> oriented, Al2O3 substrates, followed by heat treatment in a quartz tube furnace at temperatures ranging from 500 to 1000 °C.X-ray diffraction analysis reveals that films heat treated at 600 °C for 1 h are highly oriented along the c-axis direction, but the alignment is not good enough to permit channeling of 2 MeV He++ particles. Heat treatment at 900 °C improves significantly the epitaxial alignment as determined by ion-channeling measurements. However, concomitantly with the improvement in crystal orientation, the films break up into a network of LiNbO3 grains, partially uncovering the Al2O3 substrates along grain boundaries. Pole figure analysis shows that all the grains share the same in-plane orientation.
Microstructural Evolution of Epitaxial MgAl2O4 Thin Films Derived From Metal Nitrates and From Metal Alkoxides
Authors: Faing Man , Cima Michael J. 
Published: March 2011

ABSTRACTMagnesium aluminate (MgAl2O4) is a potential dielectric material in Ba2YCu3O7−x (BYC) devices. In the present study, epitaxial MgAl2O4 films were deposited on (100) SrTiO3 single crystal substrates by pyrolysis of chemical precursors. Two precursors were used: one was a mixed nitrate precursor, and the other was MgAl2(OC3H7)8. Crystallization of MgAl2O4 on lattice-Matched substrates is observed at 700°C. The average surface roughness of these MgAl2O4 films is about 6Å. These chemically-derived MgAl2O4 films have demonstrated the potential for planarization by metalorganic deposition. The relationship between the processing parameters and the surface morphology of these MgAl2O4 films will be discussed.
Molecular-Dynamics Simulations of Low-Energy Ion/Surface Interactions During Ion-Beam-Assisted Thin Film Deposition.
Authors: Feil H. 
Published: March 2011

ABSTRACTMolecular dynamics simulations are performed of low-energy ion irradiation of two-dimensional Cu islands on a Cu(111) surface. The irradiation of the surface with low-energy particles influences the mobility of the atoms in the surface region and therefore may alter the thin film growth Mode. The effect of 100 eV Ar+ ions incident at grazing angles is limited to situations in which the ions hit the edges of the islands. In Most cases the islands lose one or two atoms. Changing the angle-of-incidence or changing the type of the incident particle has a strong influence on the size distribution of the two-dimensional islands.
Structural Transformation During the Epitaxial Growth of a System with a Large Misfit: MBE Study of Ni on Au (100)
Authors: Gilles B. , Marty A. , Patrat G. , Vassent J.L. , Joud J.C. , Chamberod A. 
Published: March 2011

ABSTRACTThe growth of Ni on Au (100) has been investigated by MBE. It has been found that a Metastable BCT Ni (100) phase is coherent with the substrate up to a thickness of 5 ML. Then a structural transformation analogous to a raartensitic transition occurs, and the structure becomes FCC Ni (110). We show that the interfacial stress is progressively relieved by a high density of stacking faults, as was predicted by Bruinsma and Zangwill for epitaxial overlayers with a large Misfit.
The Role Of Steps On The Micro Structure Of Titanium-Oxide Films Deposited By Pld Onto (100) Mgo Surfaces
Authors: King Simon , Barry Carter C. 
Published: March 2011

ABSTRACTThe phenomenon of graphoepitaxy, whereby island nucleation occurs preferentially at steps, is a prime example of a manner in which the substrate morphology (and notably surface steps) can affect the microstructure of as-deposited thin-films. This paper provides a further illustration of the fundamental importance of the substrate morphology to the development of the thin-film microstructure, employing the example of TiO2 deposited by pulsed-laser deposition (PLD) directly onto specially prepared (100) MgO TEM foils. The same areas of these foils are imaged both before and after deposition.
Single-Atom Diffusion on Silver and Gold Surfaces
Authors: Boisvert Ghyslain , Lewis Laurent J. 
Published: March 2011

ABSTRACTWe present the results of a detailed Molecular-dynamics study of single-atom diffusion on the surfaces Ag (100) and (111), and Au (111), using the embedded-atom method to describe the interactions between the atoms. We find that diffusion is Arrhenius-like up to temperatures corresponding to a large fraction of the activation energy. We demonstrate, in addition, that an excellent description of the rate of diffusion is provided by a simple transition-state theory, together with parameters that derive directly from the static potential-energy surface. The Model predicts very accurately the activation energies, while the prefactor for diffusion is obtained within a factor of 2, a discrepancy we attribute to the neglect, in the Model, of the details of the structure of the surface. At higher temperatures, diffusion becomes clearly non-Arrhenius, and the model fails.
Kinetics of Surface Roughening and Smoothing During Ion Sputtering
Authors: Chason E. , Mayer T. M. , Howard A. J. 
Published: March 2011

ABSTRACTWe have measured the kinetics of roughness evolution during low energy ion sputtering of SiO2 surfaces using in situ X-ray reflectivity. Sputtering with heavy ions (Xe) leads to rapid roughening of the surface that can not be explained by a simple random removal process. Subsequent bombardment with light ions (He, H) leads to an exponential decrease in the surface roughness. These kinetics are explained quantitatively by a linear model that contains a balance between smoothing by surface diffusion and viscous flow and roughening by sputter removal of Material. A curvature dependent sputter yield leads to amplification of a limited range of spatial frequencies on the surface and the formation of a ripple topography.
Tem Investigations of CdTe/GaAs(001) Interfaces
Authors: Angelo J.E. , Gerberich W.W. , Bratina G. , Sorba L. , Franciosi A. , Mills M.J. 
Published: March 2011

AbstractIn this study, cross-sectional transmission electron microscopy (XTEM) was used to investigate the defect structure at the interface between CdTe(001) and GaAs(001) as well as CdTe(1 11) and GaAs(001). The heterostructures were fabricated by molecular beam epitaxy on GaAs(001) buffer layers grown in-situ by molecular beam epitaxy. The defect structure at the as-deposited CdTe(001)/GaAs(001) interface consists of both dislocations and planar faults. The planar faults are both microtwins and stacking faults. It is found that annealing of the film ex-situ causes a restructuring of the CdTe near the interface, with the microtwins being completely removed upon annealing to 450°C for 100 hours. The CdTe(111)/GaAs(001) thin film structure consists of a large number of microtwins parallel to the growth direction. This twinned structure is shown to be related to the relaxation of a residual misfit strain normal to the twin direction. Possible mechanisms for the relaxation are discussed.
Relationship Between Crystal Defects, Ge Outdiffusion and V/III Ratio in MOVPE Grown (001) GaAs/Ge
Authors: Frigeri C. , Atrolini G. , Pelosi C. , Longo F. 
Published: March 2011

AbstractTwo regimes of defect generation have been found in MOVPE GaAs/Ge layers upon changing the V/III ratio between 1.3 and 11.8. For low V/III ratio the layers contained misfit dislocations along with stacking faults that had been generated by dissociation of the misfit dislocations. The stacking fault density increased with decreasing V/III ratio. This might be explained by an enhanced mobility of the dissociated partials due the reduced unintentional doping of the layer caused by reduced Ge outdiffusion from the substrate when V/III is small. The secon regime corresponds to high V/III ratios and is characterized by the absence of misfit dislocations and the presence of a high density of planar defects. This means that breakdown of the 2D layer-by-layer growth occurred and 3D island growth prevailed.
Hrem Investigation of Ai-MgO Interface
Authors: Vellinga W.P. , Verwerft M. , De Hosson J.Th.M. , Hibma Tj. 
Published: March 2011

AbstractA metal-ceramic interface was produced by depositing Al on a {100} MgO substrate in a MBE system. The interface was studied with High Resolution Electron Microscopy. Results of some image simulations are shown, raising the question if effects of ionicity and charging should be taken into account.
Behavior of Damage in Selectively Implanted SiGe/Si
Authors: Theodore N. David , Tam Gordon , Whitfield Jim , Christiansen Jim , Steele John 
Published: March 2011

AbstractEpitaxial SiGe/Si layers are being extensively investigated for use in base regions of high-speed heterojunction bipolar-transistors (HBTs). Extended defects can be formed in SiGe/Si layers by ion-implantation. Defects, once formed in the layers, can negatively impact electrical performance and also future reliability of the HBTs. The present study investigates the interaction between selective-implant damage and strained SiGe/Si layers of sub-critical thickness. Implant-damage is observed to form dislocation-sources at the edges of implanted regions in SiGe/Si heterolayers. The dislocation sources produce glide dislocation loops. Segments of these loops glide down to SiGe/Si interfaces causing misfit dislocations to arise at interfaces in the heterolayers. Misfitdislocations are formed in directions parallel to and perpendicular to the <110> edge of the implanted region. Dislocations propagate out to a distance of ∼100-150 nm past the edge of the implant in the case of Si0.9Ge0.1/Si layers of sub-critical thickness. The origin and behavior of these defects is discussed.
Defect Growth Interruption Phenomena Related to Impurity Atoms in Growing Multilayer Si-Si1−x Gex Systems Deposited by APCVD
Authors: Babanskaya I. , Lippert G. , KrÜger D. , Methfessel M. , Morgenstern G. , Morgenstern T. 
Published: March 2011

AbstractThe present paper examines conditions which can lead to generation or blocking of structural defects as observed in the deposition of the Si-Si1−x Gex heterostructures prepared by conventional AP CVD. The lowering of the epitaxial temperature can lead to a breakdown of the epitaxial growth and to a generation of defects such as dendritically grown polycrystalline inclusions. Their generation depends on the moisture and oxygen content in the gas mixture. Fast cooling during growth of the underlying buffer layer leads to defect growth interruption and is attributed to the influence of hydrogen adsorption / desorption. A similar defect growth blocking has been found by addition of diborane to the gas mixture during CVD deposition.
Diffusion of Ge Along Grain Boundaries During Oxidation of Polycrystalline Silicon-Germanium Films
Authors: Edwards W. J. , Tsutsu Hiroshi , Ast D. G. , Kamins T. I. 
Published: March 2011

AbstractPolycrystalline silicon-germanium alloys with compositions between 5 and 30% Ge were wet oxidized in pyrogenic steam with TCA at 700°C. TEM showed that the columnar structure and grain size, ∼500Å, were independent of composition and did not change during oxidation. Both energy dispersive x-ray spectroscopy (EDS) in a UHV STEM and RBS indicate that for low Ge containing films (≤20% Ge), Ge is rejected from the growing oxide, whereas for films with a greater Ge concentration, some Ge is incorporated in the oxide. In low Ge containing alloys, the average Ge profile was determined by RBS and the local Ge distribution was determined by EDS from the oxide interface to about 500Å deep into the alloy. A Ge rich layer was observed at the oxide/poly-SiGe interface. The Ge concentration at the grain boundaries was found to be at least three times higher than that in the grains. The mean diffusion length of Ge along the grain boundaries, measured in cross-section by EDS, was about 300Å, corresponding to an effective diffusivity of about 6×10−16 cm2/s. Analysis of RBS profiles yielded an average effective diffusivity of ∼1.3×10−14 cm2/s. Both diffusivity values suggest that Ge rejected from the oxide growth front diffuses along grain boundaries since the bulk diffusivity of Ge in Si at 700°C is on the order of 10−22 cm2s/s.