Use of a reference crystal to condition the beam in the double-axis diffractometer permits the Bragg peak width to be reduced to the correlation of the two crystal reflecting ranges. Some recent applications of double axis diffractometry to the study of heteroepitaxial layers are discussed. The advantages of multiple reflections for beam conditioning and the four reflection DuMond monochromator are examined. Glancing incidence and exit diffractometry permits the study of very thin layers, down to a few tens of nanometres in thickness and both synchrotron radiation and skew reflections can be used to tune the glancing angle close to the critical angle. Recent applications of triple-axis diffraction, where an analyzer crystal is used after the specimen, to the study of very thin single epitaxial layers and multiquantum well structures are reviewed.

The techniques of X-ray topography are reviewed, with special reference to their application to the study of surface layers and thin films. The methods of section topography, white radiation topography and double and triple crystal topography are shown to be the most appropriate, with grazing or glancing incidence methods assuming special importance. Applications to the questions of epilayer mismatch and dislocation content, process-induced defects and surface damage are discussed.

While any subject associated with films evokes immediate thoughts about solid-state devices, there are other much more mature areas where it is important, such as coatings, and yet work on this entire subject is only in its infancy. Residual stresses are not only important because of their well-known effect on corrosion and mechanical properties, they can also lead to other severe problems. For example, it is now believed that stress gradients can lead to void formation and subsequent failure in metallization in electronic devices. Thus, it is not only the level of stress that can be important, but gradients across a surface of a thin stripe, or through the thickness.

The aim of this investigation was the establishment of a quantitative link between micro and macrodeformation and kinetic recovery of nickel-base Alloy 600 as well as the early detection of microcracks in this alloy when exposed to stress corrosion. To reach these objectives, X-ray rocking-curve measurements were carried out using the method known by its acronym CARCA (computer-aided rocking-curve analysis). Supported by transmission electron microscopy, a calibration curve was established relating dislocation density, X-ray rocking-curve halfwidth and strain. Applying CARCA, deformation levels and work-hardening characteristics of the alloys were measured by quantitative characterization of the induced defect structure. By correlating the analysis of the defect structure to the kinetic recovery of the alloys, including determination of the activation energies, it was possible to infer from the thermal stability of the alloys the dislocation obstacles responsible for hardening at different strain levels. It was shown that the recovery of the alloys was conditioned by their low stackingfault energy and that it depended on the strain level. Rapid recovery associated with grain boundary diffusion occurred at very small plastic strains up to about 0.7% with measured activation energies of recovery of about 25.6 Kcal/mol. At higher strains bulk diffusion was necessary to overcome the obstacles by dislocation climb with Q — 67 kcal/mol, The CARCA method proved itself to be a valuable research tool for assessing quantitatively the defect density and the mechanically and thermally induced changes. Relaxation effects, recorded by CARCA in the apex region of stressed C-rings exposed to a caustic medium, may open a path for early nondestructive detection of microcracks in stress-corrosion cracking.

Detailed x-ray double-axis rocking-curve analysis has been made of a series of silicon wafers, polished using various colloidal silicas with a number of different conditions. Significant differences, attributable to the polishing conditions, were observed in the tails of the rocking curves, using a four-reflection, non-dispersive beam conditioner. These have been compared with theoretical simulations in order to deduce the strain profile near the surface.

Many advanced semiconductor device designs require the growth of heteroepitaxial layers with lattice parameters differing by up to a few percent with respect to the substrate. X-ray diffraction offers a nondestructive method of determining the extent of relaxation. This paper discusses the sensitivity of x-ray techniques to small amounts of relaxation, describes how relaxation is measured in cubic materials for layer on (001) substrates and suggests nomenclature for the case of asymmetric relaxation.

Thin films containing periodic chemical or strain modulation (e.g. artificial superlattices or SL) are often characterized nondestructively by X-ray double-axis diffractometry. The satellite peaks from the modulated structure allow analysis of layer structure, elemental concentration and strain profile. This paper focuses on the effect of layer uniformity on the rocking curves of (001) GaAs/AlxGa1-xAsSL. Double-axis diffractometry for results from MBE samples with 800 Å SL periods and x=0.35 are compared for GaAs/AlGaAs layer thicknesses of 350/450, 400/400 and 450/350 Å. Symmetric (004) and asymmetric (315) diffraction planes are used to measure parallel and perpendicular misfit strains, layer periodicity and aluminum concentration. A modified kinematical scattering model, correcting for absorption and extinction, is used to calculate the satellite peak intensities and spacings. The relative thicknesses of GaAs and AlGaAs and the aluminum elemental concentration are optimized by matching with experimental results. The effect of nonuniform layer thickness on SL peak intensities is also investigated. The experimental results, the modified kinematical scattering calculations and dynamical theory agree closely for the 3-4 /zm thickness layers studied.

It is well known that x-ray diffraction techniques provide one of the most direct means of analyzing superlattice periodicity, layer thickness, strain, and defect structure. This suitability of x-rays is a consequence of the fact that most superlattice periods are in the range of 10 to 50 times the typical wavelength (Cuκα=1.54 Å) and are hence measurable by x-ray diffraction, and also that x-rays are non-destructive within the energy and dosage ranges needed for these studies. Applications of x-ray techniques to supperlattices have been discussed in many publications in the open literature.

A simple method for high-resolution measurement of surface misorientation in electronic materials is introduced. The technique combines laser optical alignment with double-crystal x-ray diffraction to yield a typical sensitivity of better than 1-2 arc sec. The technique can also be used to make corrections in spectrometric measurements in which commonly ignored rocking - curve errors may be significant.

An effective technique using grazing-incidence X-rays and asymmetric-Bragg diffraction (GIABD) for the characterization of crystalline phases on surfaces and structural depth-profiles in thin films is described. The application of the GIABD using both X-ray and synchrotron radiation sources for the analysis of an iron-oxide magnetic thin film previously reported to have an unexpected magnetically-dead layer is discussed. The X-ray diffraction analysis using the GIABD and the conventional θ-2θ scanning techniques detected an anti-ferromagnetic hexagonal α-Fe2O3 on the surface and a ferromagnetic tetragonal γ-Fe2O3 in the bulk of the film, respectively. The synchrotron diffraction analysis using incident angles below and above the critical angle of total reflection quantitatively determined the structural depth-profiles of α-Fe2O3 and γ-Fe2O3 in the film.

We present the results of a preliminary study of the use of polychromatic synchrotron radiation in energy-dispersive mode for the rapid characterization of thin film and multilayer materials. This technique takes advantage of the high intensity and excellent collimation properties of white beam synchrotron radiation. The glancing angle diffraction geometry allows structural depth probing as well as enhanced signal-to-noise by suppressing substrate contributions. The technique was successfully applied to metallic films a few hundred Angstroms thick, and to W-C multilayers.

The grazing-incidence X-ray diffraction (GIXD) method was employed to analyze two-layer thin films, which were the samples of Å lOO Å Au/500Å Cu/Si02 (substrate) and 250Å Cu/500Å Au/SiO2(substrate), which were prepared by the evaporation technique under the condition that the SiO2 substrate was at room temperature. Diffraction profiles were obtained at various glancing angles ( α ) and the data were analyzed as a function of α. The results were as follows : 1) Diffraction peaks were shifted to larger diffraction angles, because of the refraction of the incident X-ray beam. The angular shift has been approximated by the equation, α - α2- αc2)1/2, where αc is the total ref reflection critical angle of the material. 2) As a result of the correction of angular shift, the stress of the evaporated films was estimated to be null. 3) The broadening of the Cu diffraction peak and the enhancement of the Cu diffraction intensity occurred at angles near αc of Cu, due to the reflection of the X-ray beam at the Cu/Au interface.

X-ray diffraction is one of the most useful methods for the characterisation of thin crystalline layers or coatings. The most interesting techniques are: the identification of phases and their relative quantities, texture analysis, and residual stress measurements.

Thin layers which are transparent to the x-ray beam (in the diffracted wavelength) yield different intensities as compared with a bulk sample.

Ti-6Al-4V alloy has been nitrided in plasmas of N2 -H2 -Ar. The structure has been characterized by X-ray diffraction (XRD) for the determination of the products formed. The information was supported by elemental analysis with Auger Electron Spectroscopy (AES).

Three phases were identified as follows: δ-TiN, ε-Ti2N and α'-Ti (solid solution of nitrogen in titanium). The gas-feed composition affects the nitriding process as found from phase orientation and relative concentration of the products.

A review of the literature has shown that two major techniques are used to determine stress/strain in thin film structures: curvature measurement technique and internal stress measurement by the traditional sin2ψ technique. However, to date, there is no published comparison of the results from both techniques when they are applied to a given specimen.

In this paper we compare both methods theoretically and experimentally. We show that, while in some cases similar information is obtained from both techniques, there are cases where the two measurements give different results. We will show that, in such cases, the two methods can be complementary. Thus, they can be used to yield a more complete description of the total stress/strain tensor in the material.

Superconducting thin films (0.3-0.7μm) in the TI-Ca-Ba-Cu-0 system have been prepared on various single crystal substrates by sequential electron beam evaporation followed by appropriate sintering and annealing. Oxygen-annealed films show Tc as high as 110K and critical current densities to 600,000 A/cm2. X-ray diffraction analyses of these films show predominantly the Tl2Ca2Ba2Cu2O10 phase (c-parameter near 36Å), but some also contain up to 50 at% of the Tl2CaBa2Cu2O8 phase (c-parameter near 30Å). The complete absence of hkl reflections other than 00I demonstrates the highly oriented nature of the films as well as the absence of other Tl phases. The diffraction peaks are noticeably broader for the 36Å phase than for the 30Å phase. For a 0.7μm film such broadening is consistent with coherent sizes along the c-axis of 1200 - 1400Å and 500Å, respectively, for the 30Å and 36Å phases, and of strain values near 1.4-1.8 x 10-3 for both phases.

X-ray diffraction is especially useful in analyzing the phase-transition response of thin-film SmS to strain impressed by the two-dimensional constraints of the substrate. A biaxial-stress model is applied and extended to a randomly-oriented crystalline film. The changes in macrostress, the compliance tensor and effective Poisson's ratio are evaluated near the hulk phase transition. An analysis of crystallite size and microstrain broadening is also presented including broadening effects due to biaxial macrostrain on the randomly-oriented crystallites. These results illustrate the effect of a constraining, biaxial-stress field on the unusual elastic character of samarium monosulfide. It is demonstrated that the thin-film geometry suppresses the first-order phase transition allowing only linear changes between the semiconducting and metallic states.