Investigation of a nanocrystalline silicon phase embedded in SiOx thin films grown by pulsed laser deposition

The formation of nanocrystalline silicon clusters in SiOx, thin films has been investigated by means of micro-Raman and Fourier transform infrared spectroscopic techniques. The samples were deposited, by means of pulsed laser ablation of a silicon target in a controlled oxygen gas environment, on substrates heated up to 883 K. Experimental results show that, by appropriately varying the deposition parameters, it is possible to achieve a fully coordinated silicon dioxide phase with the contemporary development of a nanometer-sized crystalline silicon phase and/or an amorphous one. Comparison between the effect of a relatively high substrate temperature and of a post-deposition annealing treatment have been -exploited. From the line-shape analysis of the silicon TO vibrational mode Raman band, crystalline silicon volume fractions up to 90% have been estimated, while the nanocrystalline cluster sizes remained almost constant around 3.5 nm. A good agreement between our results and the predictions. of *silicon nanoclusters formation by a silicon atom diffusion-controlled mechanism has been found. (c) 2005 American Vacuum Society.