During reactive evaporation, e.g. for optical applications, energy has to be introduced into the growing film, otherwise it will not adhere well to the substrate, will not be dense and will not be completely oxidized. In case of conventional evaporation processes this energy is introduced by heating the substrate while the film is growing. The necessary temperatures are typically in the range of 250 °C – 300 °C. In case of IAD, the energy is introduced by energetic ions from a suitable ion source and substrate temperatures can be reduced, in many cases to ambient temperatures. The ion source typically produces both ions and electronically excited molecules (radicals).
Ion Assisted Deposition (IAD)