Dielectric Composite Thin Films
Abstract
Mixed composition films are widely used in gradient index and in discrete optical coatings. This study addressed the composition dependent properties of these films with special emphasis on the effect of composition on the film microstructure and structure-property relationships. One visible, Titanium dioxide-Silicon dioxide, and two potential infrared, ZnSe-SrF2 and Si- YF3, material systems were studied. The effect of composition, deposition and post-deposition treatment conditions on film properties such as intrinsic stress, moisture penetration, refractive index, optical scatter, morphology and crystallization have been investigated. The macroscopic film properties were observed to strongly depend on composition. This is not only due to 'averaging' of the properties of the pure constituents in the mixture but also because of unique film microstructures engendered by the composite chemical environment during film growth. In general many of the microstructure dependent properties (e.g., stress) vary nonlinearly with composition and cannot be predicted on the basis of the properties of the pure constituents. In this study the process conditions and compositions that produce films with low stress, smooth morphology, dense microstructure and low or no water content have been established in three material systems studied. (aw)
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1989
- Accession Number
- ADA217940
Entities
People
- H. O. Sankur