Mechanical stress and thermal-elastic properties of oxide coatings for use in the deep-ultraviolet spectral region

Mechanical stress and the structures of SiO/sub 2/, Al/sub 2/O/sub 3/, and HfO/sub 2/ single oxide layers and of high-reflection multilayer coatings deposited by reactive evaporation, plasma ion-assisted deposition, and ion-beam sputtering have been studied. The stress was related to the microstructure and to the incorporation of water by means of infrared spectroscopy. From the slopes of measured stress-temperature curves of these coatings deposited onto two substrate materials (silicon and fused silica), the biaxial moduli and the thermal expansion coefficients of the films were estimated.