Layer-thickness-dependent formation of Si-nanocrystals embedded in amorphous Si/SiO_2 multilayersformation of Si-nanocrystals embedded inamorphous Si/SiO_2 multilayers

摘要

Layer-thickness dependence of Si-nanocrystal (Si-NC) formation induced by furnace annealing in amorphous Si (a-Si) /SiO_2 multilayers is experimentally demonstrated with a radio-frequency-sputtered sample that has a-Si layers with different thicknesses. Further, a modified model is developed to explain the Si-NC formation based on the Gibbs free energy variation and it takes into account the whole formation process including nucleation and following growth. The theoretical results show that there is a lower limit of Si layer thickness below which the crystal formation cannot occur for a-Si/SiO_2 multilayers, and the oxide interfaces cannot constrain the lateral growth of Si-NCs, which may lead to their touches within the Si layers.