Structural investigations of sputter deposited thin films: reflection modeEXAFS, specular and non specular X-ray scattering

The extended X-ray absorption fine structure technique (EXAFS) in the refle ction mode was used for the ex situ investigation of sputter deposited thin films on float glass substrates. We show that a detailed analysis of the r eflectivity fine structure enables the extraction of short-range order stru ctural information such as bond distances, coordination numbers and Debye-W aller factors. The surface roughness and the density of the thin films were determined from specular and non-specular X-ray scattering experiments. Po lycrystalline Ag and Au films prepared by DC-sputtering in Ar atmospheres w ere investigated to show the potential of the technique. Both systems revea l a polycrystalline short-range order structure similar to that of the resp ective bulk materials. In contrast. amorphous structures with significantly reduced densities were found for Ta2O5 thin films prepared by reactive spu ttering in pure O-2-atmospheres. (C) 2000 Elsevier Science B.V. All rights reserved.