N-O related shallow donors in silicon: Stoichiometry investigations

摘要

For clarification of the unknown chemical composition of the electrically active N-O defects in silicon, an ingot with variable oxygen content and fixed nitrogen concentration was investigated by infrared spectroscopy. Shallow donor spectra taken at different sample positions, i.e., oxygen concentrations, show a strong oxygen influence on the absorption of the different N-O species, allowing determination of the number of oxygen atoms for each species via the corresponding mass-action law. From that, the energetically deepest defect N-O-5 is associated with a NO configuration, whereas the strongest complex N-O-3 has NO_2 composition. Further members of the shallow donor family contain three oxygen atoms.