The binding energies to silver (111) surface of a silver ad-atom and its cluster have been calculated. The activation energies of motion of these ad-atom clusters, vacancies and divacancies on silver (111) surface have been calculated by use of n-body embedded atom potentials and molecular dynamics.

The Microstructure of films is a result of the interplay of nucleation and growth processes which occur during deposition. A columnar structure is characteristic of films irrespective of the material or the deposition process. The length scale of the microstructure depends systematically on the atomic mobility during growth.

Synchrotron white-beam (polychromatic) x-ray radiation was used in a transmission Laue study of texture in monolithic mo films and Mo/W Multilayers. High intensity synchrotron radiation permits x-ray diffraction study of mo specimens >100μm in thickness, while 6μm is the practical thickness limit for a transmission study using a rotating anode x-ray source. The transmission Laue technique permits the collection of preferred orientation data from several families of diffracting planes on one photographic exposure. Polychromatic x-rays facilitate collection of diffraction information from a range of planar orientations without altering the orientation of the sample with respect to the incident x-ray beam. The texture information from a 35μm thick monolithic mo film and a 31μm thick multilayer of mo and W is presented. Two-fold symmetry seen in the {211} plane diffraction ring of the multilayer demonstrated both an in-plane and out-of-plane texture with a <110> growth direction. Three fold symmetry seen in the {310} and {222} plane diffraction rings of the monolithic mo film demonstrated both in-plane and out-of-plane texture which suggests a <111> growth direction.

We have investigated Epitaxial Grain Growth (EGG) in polycrystalline Ag films on Ni (001) substrates. EGG is driven by minimization of crystallographically anisotropie free energies such as the film/substrate interfacial energy and the film strain. Under some conditions EGG results in the preferred growth of the (111) epitaxial orientations that are predicted to minimize the interfacial energy. However, when Ag films are deposited on Ni (001) at low temperature, EGG experiments consistently find that (111) oriented grains are consumed by grains with (001) orientations predicted to have much higher interface and surface energy. The large elastic anisotropy of Ag can account for this discrepancy. The film thickness and the deposition temperature (relative to the grain growth temperature) determine whether strain energy or interface energy minimization dominates orientation evolution during grain growth.

We 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.

We have modelled the microstructural evolution of polycrystalline thin films during grain growth under the situation in which grain boundary migration becomes impeded by solute drag. For this we use a two-dimensional simulation of capillarity-driven grain growth in which grain boundaries migrate at velocities proportional to local curvature. At high driving forces, corresponding to high curvatures, the boundaries are given a mobility corresponding to drag-free motion. At low driving forces, corresponding to curvatures less than some critical value, the boundaries are given a lower mobility which models the effect of solute drag. During grain growth the average curvature of boundary segments decreases. When the boundary curvatures begin to fall below the critical curvature, the grain size distribution evolves to a lognormal distribution, which is maintained as significant further grain growth occurs. This is in accordance with many experimental grain size distributions which are commonly observed to be lognormal.

Grazing 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.

We report quantitative mesoscopic calculations of diffusive creep in polycrystals under external stress. The analysis includes mass transport both in the grains and along the grain boundaries, fully coupled with elastic deformations in the grains and the evolution of the displacement field. We find that the net creep rate depends strongly on the details of grain boundary arrangements. The calculations represent a first step toward a comprehensive first-principles theory of plasticity.

MgO 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.

The effects of thermal annealing at 400°C in 5 MTorr of N2 on the structural and electrical properties of thin films of InN grown at 100°C on native and AIN-nucleated (00.1) sapphire by reactive magnetron sputtering have been studied. The variations in the properties of the two sets of films have qualitatively similar, yet quantitatively different dependencies on anneal time. In each case, surface decomposition to give (101) textured rods of elemental indium is seen at short anneal times, and markedly so in the more highly strained films on the AIN-nucleated substrates. The electrical properties in both cases improve with annealing time, yielding a Hall Mobility that is enhanced 2–3 times relative to as-deposited films and similar to that for films grown at a substrate temperature of 400°C. The evolution of the electrical properties appears to be relatively insensitive to the surface decomposition and to largely reflect the nature of the bulk InN Matrix.

The 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.

It is important that inherent strains (or stresses) be controlled during thin film processing. This study used grazing incidence x-ray scattering (G1XS) to determine the strain gradient present in a ∼1700 Å sputtered molybdenum thin film. In particular, the gradient in the hydrostatic strain was Measured. This observation corresponded to assessing the average change in the lattice parameter as a function of depth throughout the thickness of the film. In addition, the strain ellipsoids, which represent the state of strain in three dimensions, were calculated as a function of film depth. It was shown that the strain varied throughout the ∼1700 Å Mo film thickness and that the principal strains were anisotropic, with one principal strain much larger than the others in Magnitude.

This paper presents the results of a detailed study of titanium - aluminum thin film multilayers fabricated using UHV Magnetron sputtering. Transmission electron Microscopy (TEM) techniques have been used to characterize the structure of these multilayers and to study the various structural transitions as a function of the composition modulation wavelength (CMW). Evidence is presented which indicates the existence of a titanium based fcc structure in these films, below a critical CMW. At even smaller values of CMW, both the Ti and Al layers adopt the hep structure and are coherent with each other. The evolution of thin film microstructure has been studied using high resolution TEM (HRTEM) and an attempt is made to rationalize the stability of different phases based on the energetics of atomic stacking.

In 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.

Pulsed-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.

Molecular dynamics simulations of nickel and carbon have been used to study the phenomena due to ion impact. The nickel and carbon interactions were described using the Lennard-Jones and Stillinger-Weber potentials respectively. The phenomena occurring after the impact of 100 e V to 1 keV ions were studied in the nickel simulations, which were both two and three-dimensional. Supersonic focussed collision sequences (or focusons) were observed, and associated with these focusons were unexpected sonic bow waves, which were a major energy loss mechanism for the focuson. A number of 2D carbon films were grown and the stress in the films as a function of incident ion energy was Measured. With increasing energy the stress changed from tensile to compressive and reached a maximum around 50 eV, in agreement with experiment.

Thin films of Ti, Al, TiAl and Ti3Al were deposited by dc magnetron sputtering onto 2” dia. oxidized Si<111> wafers and their mechanical properties were studied by measuring the internal stress in the films. Ti and Ti3Al films show hexagonal structure with preferred orientation in the (0002) direction. TiAl is tetragonal, nanocrystalline, and (111) oriented; Al is random fee polycrystalline in nature. Young's Modulii of thin films of these materials were calculated from the stress temperature plots. The E values of TiAI and Ti3Al thin films were found to be significantly higher than those of the bulk Materials.

The etching and growth behavior of diamond in CxFy / O2 / H2 plasmas have been investigated. Using this gas Mixture, diamond can nucleate on untreated tungsten carbide and silicon carbide substrates up to a density of 108 crystallites/cm2. This compares to a density of 102 crystallites/cm2 when using a methane gas mixture and these same substrates. The increase in nucleation density is attributed to the selective etching of the non-carbon component of the carbide with subsequent nucleation on the carbon enriched surface. The effect of temperature on the nucleation rate has been studied with a lower nucleation density at higher growth temperatures.

The 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.

Zeolites have been used as a potential substrate for CVD diamond deposition. By saturating the pore channels of a silicalite crystal, which are spaced approximately 10 Å apart, with hydrocarbon seeds to induce and control nucleation, films have been grown in a hot filament chemical vapor deposition (HFCVD) system under standard deposition conditions, using acetone as the carbon source. The hydrocarbons used were adamantane, naphthalene, anthracene, 2,3-benzanthracene, and l,2:5,6-dibenzanthracene. To enhance nucleation, a high pressure pre-deposition period was used initially.

Characterization of these films through electron diffraction and Auger electron spectroscopy indicates that polycrystalline β-SiC imbedded in an amorphous matrix is initially formed and large, well faceted diamond crystals are subsequently nucleated.