Interdiffusion in vacuum-deposited dielectric thin films

The observation of interdiffusion imperfection in vacuum-deposited optical thin films is reported. We measured the diffusion lengths of interdiffusion in dielectric thin films of typical combinations of coating materials (TiO 2-SiO2 and TiO2-MgF2) by analyzing the atomic concentration data along the depth obtained with X-ray photoelectron spectroscopy technique. The resulta nt diffusion lengths in the deposited layers of dielectric coating material s are not small, hence the effects of interdiffusion should be taken into a ccount in the design of optical filters. (C) 2001 Published by Elsevier Sci ence B.V.