Kardar-Parisi-Zhang growth of amorphous silicon on Si/SiO2

Amorphous silicon films with thicknesses ranging from about 20 Angstrom to 2000 Angstrom were evaporated onto silicon substrates. The surface and interfaces were then investigated by specular and diffuse x-ray scattering experiments in the region of total external reflection. A model of self-affine interfaces was used for the refinement. The rms roughness sigma and the in-plane correlation length xi vs film thickness follow power laws with exponents of beta=0.1+/-0.05 and 1/z=0.6+/-0.2, and the average Hurst parameter is h=0.23+/-0.05. The resulting parameters are compatible with growth models based on the Kardar-Parisi-Zhang equation.