With contributions by Paul F. Fewster and Christoph Genzel While X-ray diffraction investigation of powders and polycrystalline matter was at the forefront of materials science in the 1960s and 70s, high-tech applications at the beginning of the 21st century are driven by the materials science of thin films. Very much an interdisciplinary field, chemists, biochemists, materials scientists, physicists and engineers all have a common interest in thin films and their manifold uses and applications. Grain size, porosity, density, preferred orientation and other properties are important to know: whether thin films fulfill their intended function depends crucially on their structure and morphology once a chemical composition has been chosen. Although their backgrounds differ greatly, all the involved specialists a profound understanding of how structural properties may be determined in order to perform their respective tasks in search of new and modern materials, coatings and functions. The author undertakes this in-depth introduction to the field of thin film X-ray characterization in a clear and precise manner.

With contributions by Paul F. Fewster and Christoph Genzel While X-ray diffraction investigation of powders and polycrystalline matter was at the forefront of materials science in the 1960s and 70s, high-tech applications at the beginning of the 21st century are driven by the materials science of thin films. Very much an interdisciplinary field, chemists, biochemists, materials scientists, physicists and engineers all have a common interest in thin films and their manifold uses and applications. Grain size, porosity, density, preferred orientation and other properties are important to know: whether thin films fulfill their intended function depends crucially on their structure and morphology once a chemical composition has been chosen. Although their backgrounds differ greatly, all the involved specialists a profound understanding of how structural properties may be determined in order to perform their respective tasks in search of new and modern materials, coatings and functions. The author undertakes this in-depth introduction to the field of thin film X-ray characterization in a clear and precise manner.

During the last 20 years interest in high-resolution x-ray diffractometry and reflectivity has grown as a result of the development of the semiconductor industry and the increasing interest in material research of thin layers of magnetic, organic, and other materials. For example, optoelectronics requires a subsequent epitaxy of thin layers of different semiconductor materials. Here, the individuallayer thicknesses are scaled down to a few atomic layers in order to exploit quantum effects. For reasons of electronic and optical confinement, these thin layers are embedded within much thicker cladding layers or stacks of multilayers of slightly different chemical composition. It is evident that the interface quality of those quantum weHs is quite important for the function of devices. Thin metallic layers often show magnetic properties which do not ap pear for thick layers or in bulk material. The investigation of the mutual interaction of magnetic and non-magnetic layers leads to the discovery of colossal magnetoresistance, for example. This property is strongly related to the thickness and interface roughness of covered layers.

During the last 20 years interest in high-resolution x-ray diffractometry and reflectivity has grown as a result of the development of the semiconductor industry and the increasing interest in material research of thin layers of magnetic, organic, and other materials. For example, optoelectronics requires a subsequent epitaxy of thin layers of different semiconductor materials. Here, the individuallayer thicknesses are scaled down to a few atomic layers in order to exploit quantum effects. For reasons of electronic and optical confinement, these thin layers are embedded within much thicker cladding layers or stacks of multilayers of slightly different chemical composition. It is evident that the interface quality of those quantum weHs is quite important for the function of devices. Thin metallic layers often show magnetic properties which do not ap pear for thick layers or in bulk material. The investigation of the mutual interaction of magnetic and non-magnetic layers leads to the discovery of colossal magnetoresistance, for example. This property is strongly related to the thickness and interface roughness of covered layers.

The properties of soft-matter thin films (e.g. liquid films, polymer coatings, Langmuir-Blodgett multilayers) nowadays play an important role in materials science. They are also very exciting with respect to fundamental questions: In thin films, liquids and polymers may be considered as trapped in a quasi-two-dimensional geometry. This confined geometry is expected to alter the properties and structures of these materials considerably. This volume is dedicated to the scattering of x-rays by soft-matter interfaces. X-ray scattering under grazing angles is the only tool to investigating these materials on atomic and mesoscopic length scales. A review of the field is presented with many examples.

Nanometric thin films are used widely throughout various industries and for various applications. Metallic thin films, specifically, are relied upon extensively in the microelectronics industry, among others. For example, alloy thin films are being investigated for CMOS applications, tungsten films find uses as contacts and diffusion barriers, and copper is used often as interconnect material. Appropriate metrology methods must therefore be used to characterize the physical properties of these films. X-ray scattering experiments are well suited for the investigation of nano-scaled systems, and are the focus of this doctoral dissertation. Emphasis is placed on (1) phase identification of polycrystalline thin films, (2) the evaluation of the grain size and microstrain of metallic thin films by line profile analysis, and (3) the study of morphological evolution in solid/solid interfaces. To illustrate the continued relevance of x-ray diffraction for phase identification of simple binary alloy systems, Pt-Ru thin films, spanning the compositional range from pure Pt to pure Ru were investigated. In these experiments, a meta-stable extension of the HCP phase is observed in which the steepest change in the electronic work function coincides with a rapid change in the c/a ratio of the HCP phase. For grain size and microstrain analysis, established line profile methods are discussed in terms of Cu and W thin film analysis. Grain sizes obtained by x-ray diffraction are compared to transmission electron microscopy based analyses. Significant discrepancies between x-ray and electron microscopy are attributed to sub-grain misorientations arising from dislocation core spreading at the film/substrate interface. A novel "residual" full width half max parameter is introduced for examining the contribution of strain to x-ray peak broadening. The residual width is subsequently used to propose an empirical method of line profile analysis for thin films on substrates. X-ray reflectivity was used to study the evolution of interface roughness with annealing for a series of Cu thin films that were encapsulated in both SiO2 and Ta/SiO2. While all samples follow similar growth dynamics, notable differences in the roughness evolution with high temperature ex-situ annealing were observed. The annealing resulted in a smoothing of only one interface for the SiO2 encapsulated films, while neither interface of the Ta/SiO2 encapsulated films evolved significantly. The fact that only the upper Cu/SiO2 interface evolves is attributed to mechanical pinning of the lower interface to the rigid substrate. The lack of evolution of the Cu/Ta/SiO2 interface is consistent with the lower diffusivity expected of Cu in a Cu/Ta interface as compared to that in a Cu/SiO2 interface. The smoothing of the upper Cu/SiO2 interface qualitatively follows that expected for capillarity driven surface diffusion but with notable quantitative deviation.

The 38th Annual Denver Conference on Applications of X-Ray Analysis was held July 31 - August 4, 1989, at the Sheraton Denver Technical Center, Denver, Colorado. The conference alternates emphasis between x-ray diffraction and x-ray fluorescence, and this being an odd year the emphasis was on diffraction. Thus the Plenary Session was slanted toward diffraction in general and thin film analysis in particular. The Plenary Session on x-ray analysis of thin films did not just happen this year but really began four years ago with Paul Predecki suggesting a special session devoted to thin film techniques. The session generated a great deal of interest, so Paul suggested that a workshop on thin films should be slated for the 1987 conference. A full day was devoted to the workshop, which was split into a half day on epitaxial thin films and the other half day on polycrystalline thin films. The workshop attendance indicated a great deal of interest in this topic, leading to this year's Plenary Session. The first two speakers of the Plenary Session (B. Tanner and K. Bowen) have been key throughout the thin film activities. They were invited speakers for the 1985 special session on thin films and instructors for the 1987 workshop on epitaxial thin films.