Surface and interface topography of amorphous SiO2/crystalline Si(100) studied by X-ray diffraction

Abstract
Several samples of a-SiO2/c-Si(100) with different oxide layer thicknesses and different silicon surface qualities were examined by X-ray diffraction. The layer thickness as well as the surface roughness and the interface roughness were studied by measuring the reflectivity of the samples near total external reflection. A separate and detailed determination of the interface roughness is obtained by analysing the intensity near the Si(400) reciprocal lattice point. There is a pronounced diffuse scattering parallel to the normal of the interface, the frequently called crystal truncation rods. Both the reflectivity and the isointensity contours around the (400) reflection demonstrate the presence of an intermediate layer between a-SiO2 and c-Si in a crystalline state.