[en] The channeling effect technique was applied to investigate dechanneling by dislocations in Al-implanted crystals and by stacking faults in heteroepitaxially grown silicon layers. For these defects direct backscattering has been found negligible with respect to dechanneling. Analysis of ion backscattering data for several analyzing beam energies shows that dislocation dechanneling increases with the square root of the beam energy. Stacking-fault defects are characterized by an energy-independent dechanneling cross-section. Comparison with transmission electron microscopy allows the quantitative determination of the cross-sections which compare well with existing calculated values. Large densities of dislocations and stacking-faults are necessary for channeling analysis