XPS and SIMS investigation on the role of nitrogen in Si nanocrystals formation

In fact it is possible to obtain similar samples with very different nitrogen content in the silica matrix changing one of the precursor gases used in the deposition process, thus evidencing the structural and chemical differences introduced by the presence of nitrogen. In this paper SIMS and XPS analysis of two series of similar samples, but with a very different nitrogen content, will be presented and compared. The data collected at different annealing temperatures, together with ellipsometric measurements, give important information on the role played by the nitrogen present in the matrix in the process of silicon nanocrystal formation. Moreover, we demonstrate that the annealing process causes always some oxidation of the sample surface and that nitrogen is incorporated in the material from the annealing atmosphere in nitrogen free samples.