Silicon nanocluster in silicon nitride: photoluminescence, Raman scattering and ESR studies

An investigation on the atomic and electronic properties of silicon nitride using Raman, photoluminescence and ESR measurement was conducted. Silicon nitride films with different silicon/nitrogen ratio (SiN_x, 0.6<x<1.3) were prepared. Some of the samples underwent excimer laser annealing to study the formation of crystallites. Raman results show that silicon nanoclusters can be formed in silicon nitride by introducing excess silicon. We also found that the luminescence properties of silicon nitride are governed by the silicon composition. From ESR measurement, we confirm that the silicon trivalent atoms or Si₃Si centers (g=2.0046) are dominant in samples with excess silicon. This kind of recombination center is responsible for the decrease in luminescence intensity in high silicon concentration samples