Quantitative ASAXS of germanium inhomogeneities in amorphous silicon-germanium alloys

The nanostructure of hydrogenated amorphous silicon germanium alloys, a-Si(1-x)Ge(x):H (x similar to 0.15 to 0.57), prepared by different plasma enhanced chemical vapor deposition (PECVD) techniques was analyzed by anomalous small-angle X-ray scattering (ASAXS) experiments. For alloys with x > 0.2 the Ge component was found to be inhomogeneously distributed with correlation lengths from 0.6 to 1.6 nm. From the analysis of extended ASAXS measurements at 16 X-ray energies in combination with densitometric measurements the volume fractions, densities and Ge-concentrations of the inhomogeneities were deduced. (C) 2001 Elsevier Science B.V. All rights reserved.