The influence of deposition parameters on the structure of nanocrystallinesilicon

The structure. hydrogen content and bonding configurations of nanocrystalli ne silicon films produced by PECVD using hydrogen-diluted silane have been investigated by Raman and IR-spectroscopies. The film structure has been st udied in relation to deposition parameters, such as gas dilution ratio, amo unt of water vapor in the initial gas, substrate temperature (T-s) and the substrate material. An analysis of Raman spectra has revealed in the films nanocrystallites embedded in amorphous matrix. The crystallite size (L) is in the range 3.6-5.7 nm. The volume fraction of crystallises (X-c) varies b etween 15% and 81%, depending on preparation conditions. Both L and X-c are primarily influenced by the presence of water vapor in the initial gas and the substrate material, while the effect of T-s is less pronounced. IR dat a show the presence of bound hydrogen with a total concentration varying be tween 3 and 13 at.%. (C) 2000 Elsevier Science S.A. All rights reserved.