Deep levels in Er-doped liquid phase epitaxy grown silicon

The optical activity of Er-doped silicon is related to the presence of defects which enhance the typicaI radiative transition at 0.8 eV but whose nature and properties are still largely unknown. We have investigated the deep levels present in Er-doped liquid phase epitaxy silicon to identify the traps possibly related to the luminescence. Among the observed levels, two minority carrier traps labeled E2 (E-C-0.20 eV) and E3 (E-C-0.39 eV), and one majority carrier trap labeled H1 (E-v +0.32 eV) are good candidates for the material optical activity. The onset of luminescence occurs after a thermal treatment and is accompanied by a high space charge density localization at the epilayer-substrate interface. (C) 1998 American Institute of Physics.