Grazing incidence small-angle x-ray scattering from defects induced by helium implantation in silicon

Abstract

The formation and growth of defects, including nanocavities and extended interstitial-type defects, created by helium implantation in silicon (50keV, 7.1015cm−2) in the temperature range of 100–550°C has been investigated by grazing incidence small-angle x-ray scattering. We show that quantitative information can be obtained on the size distribution, shape dispersion (i.e., anisotropy and faceting versus the size), and depth profile of the nanocavities from the near surface to deeply buried regions up to 1μm. It is thus demonstrated that low temperature implantations (⩽200°C) lead to the formation of spherical nanocavities with a heterogeneous depth distribution whereas implantations at high temperatures (⩾300°C) cause growth of the cavities, broadening of the size distribution, and size-dependent faceting leading to a size-dependent shape anisotropy. Furthermore, we show that the method allows to characterize the morphology (i.e., width and thickness) and the evolution of extended planar {113} defects created during the implantation process at high temperatures.