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Specular Reflectivity (specular + reflectivity)
Selected AbstractsGenX: an extensible X-ray reflectivity refinement program utilizing differential evolutionJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 6 2007Matts Björck GenX is a versatile program using the differential evolution algorithm for fitting X-ray and neutron reflectivity data. It utilizes the Parratt recursion formula for simulating specular reflectivity. The program is easily extensible, allowing users to incorporate their own models into the program. This can be useful for fitting data from other scattering experiments, or for any other minimization problem which has a large number of input parameters and/or contains many local minima, where the differential evolution algorithm is suitable. In addition, GenX manages to fit an arbitrary number of data sets simultaneously. The program is released under the GNU General Public License. [source] Structural analysis of thin films of novel polynorbornene derivatives by grazing incidence X-ray scattering and specular X-ray reflectivity along with ellipsometryJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 2007Taek Joon Lee In the present study, structural analyses using synchrotron grazing incidence X-ray scattering, specular reflectivity and ellipsometry were performed on thin films of two novel polynorbornene derivatives, chiral poly(norbornene acid methyl ester) and racemic poly(norbornene acid n -butyl ester), which are potential low dielectric constant materials for advanced microelectronic and display applications. These analyses provided important information on the structure, electron density gradient across the film thickness, chain orientation, refractive index and thermal expansion characteristics of the polymers in substrate-supported thin films. The structural characteristics and properties of the thin films depended on the tacticity of the polymer chain and were further influenced by the film thickness and thermal annealing history. [source] Effects of Thermal Annealing on the Structure of Ferroelectric Thin FilmsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 4 2006Jiang-Li Cao The effects of thermal annealing on the structure of polycrystalline Pb(Zr0.3Ti0.7)O3 (PZT) ferroelectric thin films prepared by chemical solution deposition on Pt/TiOx electrode stacks were studied using scanning electron microscopy, transmission electron microscopy (TEM), and grazing incidence X-ray specular and diffuse reflectivity of synchrotron radiation. The stratified multilayered structure and element diffusions in the sample were characterized by TEM. Global statistical structural parameters including the density, surface or interface roughness and thickness of each layer in the samples were obtained from fitting the X-ray specular reflectivity using a homogeneous stratified multilayer model of PZT/Pt/TiOx/SiO2. The results showed that the PZT surface and PZT/Pt interface roughness changed slightly during thermal annealing in oxygen at 700°C. By contrast, the density increase of the PZT ceramic and density decrease of the Pt-bottom electrode during annealing were observed. A high density value of the PZT ceramic film after the annealing was found, up to 99.8% of the theoretical value of the corresponding bulk ceramics. The density changes of the PZT and Pt layers were further confirmed by X-ray diffuse reflectivity. The influences of the annealing treatment on the density changes of the PZT and Pt layers were attributed to the further densification of the PZT ceramic and incorporation of light elements such as Zr, Ti and O from the neighboring layers into the Pt layer, respectively, as discussed in correlation with the TEM analyses. [source] Interdiffusion in SiGe alloys with Ge contents of 25% and 50% studied by X-ray reflectivityPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 10 2008M. Medun Abstract The interdiffusion in SiGe alloys has been studied by X-ray specular reflectivity using ex-situ and in-situ annealing experiments. We report on the evolution of the Ge profile of strain-compensated Si/SiGe multilayers due to high temperature annealing. These multilayers were grown pseudomorphically and strain-symmetrized on relaxed Si0.75Ge0.25 and Si0.5Ge0.5 pseudosubstrates by molecular beam epitaxy at 330 °C. The multilayer structures were annealed at several temperatures around 590 °C and around 800 °C. From modelling the X-ray specular reflectivity scans at various stages of the interdiffused structures, we obtained interdiffusion coefficients resulting in the activation energy and the prefactor for interdiffusion corresponding to Si0.75Ge0.25 and Si0.5Ge0.5. The results obtained ex-situ for Si0.5Ge0.5 and in-situ for Si0.75Ge0.25 provide accurate values of diffusion parameters. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Initial growth stages of MOVPE InN studied by AFM and specular reflectivityPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 1 2007A. van der Lee Abstract The initial growth of InN grown by MOVPE was investigated by a combination of atomic force microscopy (AFM) and X-ray specular reflectivity for five different thin films ranging from 57 to 750 Å. Both AFM and specular reflectivity measurements show that during the initial growth the surface is not completely covered but that instead a discontinuous layer resembling quasi two-dimensional islands is formed. Dots with heights between 30 and 100 nm appear at the same time; the number density of these dots decreases with increasing thickness. At 750 Å the surface is completely covered and obtains a granular aspect. The surface coverage of the discontinuous wetting layer is discussed in relation with the apparent porosity calculated from the specular reflectivity data. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||