Photoluminescence induced by Si implantation into Si3N4 matrix

Up to the present, photoluminescence (PL) was obtained from near stoichiometric or amorphous Si nitride films (SiNx) after annealing at high temperatures. As a consequence, the existence of PL bands has been reported in the 400-900 nm range. In the present contribution, we report the first PL results obtained by Si implantation into a stoichiometric 380 nm Si3N4 film. The Si excess is obtained by a 170 keV Si implantation at different temperatures with a fluence of Phi = 10(17) Si/cm(2). Further, we have annealed the samples in a temperature range between 350 and 900 degrees C in order to form the Si precipitates. PL measurements were done using an Ar laser as an excitation source, and a broad PL band basically centered at 910 nm was obtained. We show that the best annealing condition is obtained at T-a = 475 degrees C for the samples implanted at 200 degrees C, with a PL yield 20% higher than the obtained at room temperature implantation. Finally, we have varied the implantation fluence and, consequently, the Si nanocrystals size. However, no variation was observed nor in the position neither in the intensity of the PL band. We concluded that the PL emission is due to radiative states at the matrix and the Si nanocrystals interface, as previously suggested in the literature. (C) 2009 Elsevier B.V. All rights reserved.