Visible photoluminescence from silicon nanoclusters embedded in silicon nitride films prepared by remote plasma-enhanced chemical vapor deposition

The photoluminescence (PL) of silicon nanoclusters embedded in silicon nitride films grown by remote plasma-enhanced chemical vapor deposition at 200 °C, using mixtures of SiCl4/H2/Ar/NH3 is investigated. It was found that the color and the intensity of the PL of the as-grown samples depend on the H2 flow rate, and there is an optimum flow for which a maximum luminescence is obtained. A strong improvement of the PL intensity and change in color was obtained with annealing treatments in the range of 500–1000 °C. The changes in the composition, structure and optical properties of the films, as a function of H2 flow rate and thermal treatments, were studied by means of Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, ellipsometry and ultraviolet–visible transmission measurements. We conclude that the PL can be attributed to quantum confinement effect in silicon nanoclusters embedded in silicon nitride matrix, which is improved when a better passivation of the nanoclusters surface is obtained.