Enhanced Luminescence of Erbium Doped Silicon Due to Hydrogen

Erbium- and oxygen-doped silicon was additionally doped with hydrogen, using plasma-enhanced Chemical Vapor Deposition. Samples treated with solid-phase epitaxy (SPE) before hydrogen doping and annealing at 900 °C after show a large enhancement of the photoluminescence yield. Secondary Ion Mass Spectroscopy gives evidence for an enhanced diffusion of both oxygen and erbium at this temperature towards the surface. This change in local concentration leads to a dominance of the cubic center that is usually only found for lower Er concentrations. Controlled etching shows that the PL does stem from a deeper region with lower erbium concentration. The luminescence yield in the hydrogenated samples is significantly higher even if compared to samples prepared to optimize the cubic center luminescence. We thus conclude that hydrogen can enhance the solubility of the cubic center in Si:Er,O.