Silicon clusters in PECVD silicon-rich SiO x N y R.A.R. Oliveira, M. Ribeiro, I. Pereyra * , M.I. Alayo EPUSP, University of Sa ˜o Paulo, CP 61548, CEP 5424-970, Sa ˜o Paulo, SP, Brazil Received 15 January 2003; accepted 30 March 2003 Abstract 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 SiO 2 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 SiO x N y deposited by plasma-enhanced chemical vapor deposition (PECVD) technique at low temperatures. These films were annealed at different temperatures, in N 2 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. D 2003 Elsevier Inc. All rights reserved. Keywords: Silicon oxynitride; Silicon clusters; Photoluminescence; PECVD 1. Introduction Research on the fabrication of light-emitter devices from materials compatible with silicon technology is nowadays of great importance since it would facilitate the integration of microelectronic and optical devices in a same chip. To reach these goals, it is essential to search for photoluminescent materials compatible with these two areas. Initial studies pointed to porous silicon due to its notorious photoluminescence [1–4]. However, the recognized instability of this material limits its use in luminescent devices. On the other hand, since the discovery of the photoluminescent properties of Si/SiO 2 multilayers [5], studies on silicon clusters embedded in a SiO 2 matrix are being extensively performed, mainly be- cause these materials exhibit optical properties similar to that of porous silicon but with higher stability, making the production of devices such as lasers and photodiodes possible [6,7]. Different techniques are being used to obtain silicon clusters embedded in SiO 2 films; among these we can mention: Si + ion implantation onto SiO 2 [8], plasma-enhanced chemi- cal vapor deposition (PECVD) [9], sputtering [10,11] and reactive evaporation [12]. Although numerous research studies have suc- ceeded in reaching this goal, there remains consider- able uncertainty about the mechanisms responsible for the photoluminescence in these materials. Various possibilities are proposed consistent with experimen- tal evidence. Some authors attribute the photolumi- nescence to quantum confinement effects [13–15], 1044-5803/$ - see front matter D 2003 Elsevier Inc. All rights reserved. doi:10.1016/S1044-5803(03)00086-X * Corresponding author. Tel.: +55-11-3091-5256; fax: +55-11- 3091-5585. E-mail address: ipereyra@lme.usp.br (I. Pereyra). Materials Characterization 50 (2003) 161 – 166