Depth-resolved cathodoluminescence spectroscopy of silicon supersaturated with sulfur

Abstract

We investigate the luminescence of Si supersaturated with S (Si:S) using depth-resolved cathodoluminescence spectroscopy and secondary ion mass spectroscopy as the S concentration is varied over 2 orders of magnitude \((10^{18}–10^{20} cm^{−3})\). In single-crystalline supersaturated Si:S, we identify strong luminescence from intra-gap states related to Si self-interstitials and a S-related luminescence at 0.85 eV, both of which show a strong dependence on S concentration in the supersaturated regime. Sufficiently high S concentrations in Si \((>10^{20} cm^{−3})\) result in complete luminescence quenching, which we propose is a consequence of the overlapping of the defect band and conduction band.