Low-temperature growth of nano-structured silicon thin films on ITO initiated by metal catalysts

Nano-structured silicon thin films have been grown on tin-doped indium oxide (ITO) by Plasma-Enhanced Chemical Vapor Deposition (PECVD) at temperatures lower than 200 °C. Nanometer-scaled aggregates of metal (copper or gold) obtained from evaporated layers were necessary to initiate the nano-structuring growth. Different deposition conditions have been investigated. The highest aspect ratio was obtained with copper and high-pressure plasmas with SiH4 diluted in H2. The metals help dissociating silane so the deposition starts faster on the aggregates than around them, which leads to nano-structuration. It is likely that the metal remains confined at the interface between ITO and silicon and do not diffuse in the silicon layer.