step-bunching process during the growth on vicinal Si substrates provides a
template both for improved lateral ordering and size control of the result
ing Ge-rich self-assembled quantum dots or wires. We have investigated a 20
period SiGe/Si wire multilayer grown by molecular beam epitaxy on a misori
entated Si(001) substrate with a large miscut of 3.5 degrees towards the [1
00] direction. Parallel to the steps, i.e. along the [010] direction, Ge-ri
ch wires are formed spontaneously. Their surface morphology was studied wit
h atomic force microscopy. In order to get information on the shape and the
lateral correlation not only of the wires on the top surface but also of t
he buried ones, we employed grazing incidence small-angle x-ray scattering
(GISAXS). The GISAXS data were taken for different information depths in tw
o orthogonal azimuths. Side maxims in coplanar high-angle diffraction and G
ISAXS data indicate the presence of Ge-rich self-organized wires at the bur
ied heterointerfaces.