High-resolution x-ray diffraction on self-organized step bunches of Si1-xGex grown on (113)-oriented Si

We present investigations of a highly regular terraced surface and interfac e structure of Si/SiGe multilayers on Si (113) by x-ray diffraction, x-ray reflectivity and atomic force microscopy. A regular array of step bunches w ith lateral periods of several hundred nanometres is formed during the grow th of the Si/Si1-xGex multilayers. X-ray diffraction patterns are simulated using the elastic Green function approach for the evaluation of the strain fields associated with the step edges, taking into account the relaxation towards the free surface. In addition to the terrace structure, a surface w aviness on the micrometre length scale is present, leading to a modulation of the terrace widths.