Analysis of semiconductors by ion channelling: Applications and pitfalls

Ion channelling is a rapid and powerful method for determining the perfection of single crystals and, more specifically, is sensitive to departures in the perfect arrangement of atoms in a single crystal lattice. This paper examines three of the major applications of channelling, namely lattice disorder, atom location of foreign species within a host matrix and improved sensitivity for thin film analysis. Examples are given in these three areas covering build up of implantation damage in GaN, SiO₂ and Si₃N₄ formation during SIMS analysis and atom location of Au at nanocavities in Si. These examples are shown not only to illustrate applications but also to highlight pitfalls in using channelling/Rutherford backscattering analysis of semiconductors. Such pitfalls can give rise to significant errors when the channelling stopping power alters the depth scale for profiling of damage or impurities and/or changes the energy window for atom location. Channelling oscillations can also influence the ability to obtain random spectra and interpret near-surface disorder vs. depth profiles.