Influence of oxygen pressure and substrate temperature on the properties of aluminum fluoride thin films

Single layers of AlF3 were deposited at different substrate temperature by resistant heating technique in vacuum and in certain oxygen pressure. The chemical composition, total stress, optical constants and laser damage resistance were characterized. Comparative study indicates that AlF3 films deposited under certain oxygen pressure and lower temperature tend to absorb more water when exposed to air and as a result, their total stress and optical absorption are reduced. These differences and the increased laser-induced damage threshold (LIDT) at 355 nm demonstrate that reasonable oxygen pressure and substrate temperature may improve AlF3 films' UV performance.