Channeling and steering effects on 2 MeV He 2+ ions in Ge + ion implanted SiGe-alloy layers

Abstract

Channeling and steering effects on 2 MeV He 2+ ions in Ge + ion implanted buried SiGe(100)-alloy layers were investigated by ion channeling-backscattering technique and by ion channeling angular scans through the 〈110〉 crystal axis. Except for the end-of-range defects the alloy layers are virtually defect-free. The angular shift in the 〈110〉 crystal direction of the alloy layer, from the 〈110〉 crystal direction of the silicon adjacent to the ion implanted area, was found to increase with the Ge concentration. This indicates an increase in the tetragonal distortion in the alloy layer. The measured tetragonal distortion is in agreement with that deduced from Vegard's law. The steering of the He 2+ ion beam in the alloy layer increases with the Ge concentration. The low concentration of end-of-range defects was found to have no detectable influence on the steering of the He 2+ ion beam.