Plasma enhanced deposition of corrosion resistant high reflectivity mirrors

Abstract

With the aim of developing highly reflective and corrosion resistant surface mirrors, various techniques of producing thin reflecting and protecting layers have been compared. A thin Al film of 100 nm has been used as the reflecting layer; Al 2O 3 of 10 nm thickness was employed as the protecting layer. The films were produced with thermal evaporation, with conventional sputtering methods, as well as with anodic vacuum arc evaporation, characterized by the flux ionization and the ion energy. They were deposited without the use of substrate heating. The results are compared with respect to a possible scaling up to large substrates (diameter greater than 1 m). The corrosion resistance is tested with a standard method developed by Sainty using a sodium hydroxide solution. The reflectivity of the thin films is measured in the spectral range 300–800 nm. First results are presented.