[en] The ion channeling technique has been applied to study the stacking defects in heteroepitaxially grown silicon. He ion backscattering experiments were performed on 0.4 μm Si layers grown on sapphire at a beam energy of 1.5 MeV and crystal axes of (100), (110), and (111). A comparison with a single crystal Si wafer developed comparative data which was subsequently used to analyze the depth profile of the density of imperfections. The calculation of dechanneling cross section is based upon the model of 'parallel shift of equipotential contours'. (orig.)