In recent years, the integration of optical and microelectronic devices has been of great interest, motivating studies related to the production of photoluminescent material compatible with present silicon technology. In this context, silicon clusters embedded in a SiO2 matrix are ideal candidates for these applications, mainly due to the intense emission that these new structures present, being promising for the production of devices such as lasers and photodiodes. In this work, we report the fabrication and characterization of silicon-rich SiOxNy deposited by plasma-enhanced chemical vapor deposition (PECVD) technique at low temperatures. These films were annealed at different temperatures, in N2 ambient. Fourier transform infrared spectroscopy (FTIR) and Raman scattering results showed phase segregation and crystallization in the clusters induced by heat treatment. Photoluminescence measurements showed visible emission peaks, compatible with variable size cluster distribution. © 2003 Elsevier Inc. All rights reserved.