Defect vs. nanocrystal luminescence emitted in Si-implanted SiO2 layers

Visible photoluminescence is observed from thin Si-implanted SiO2 films. Si ions were implanted into 300-nm-thick SiO2 films grown on crystalline Si a t energies of 30 and 55 keV, and with doses of 5 x 10(15) and 1 x 10(17) cm (-2). Implanted samples were subsequently annealed in N-2 ambient at 500-11 00 degrees C. PL spectra for the sample implanted with 1 x 10(17) cm(-2) at 55 keV show that red luminescence (750 nm) related to Si-nanocrystals clea rly increases with annealing temperature in intensity, and that a weak oran ge luminescence (600 nm) is observed after annealing at low temperatures of 500 and 800 degrees C. The luminescence around 600 nm becomes very intense when a thin SiO2 sample is implanted at a substrate temperature of 400 deg rees C with an energy of 30 keV and a dose of 5 x 10(15) cm(-2). After anne aling the sample in forming gas the PL intensity remarkably decreases. It i ndicates that defects are passivated by hydrogen. We conclude that this lum inescence observed around 600 nm is caused by some radiative defects formed in Si-implanted SiO2.