Abstract

Wide bandgap metal fluorides are the materials of choice for optical coating applications at $193\mathrm{nm}$. Low loss and environmentally stable optics requires a mitigating fluoride film structure on a nanometer scale. To understand the growth mechanism of fluoride materials, $\mathrm{Gd}{\mathrm{F}}_3$ films grown on $\mathrm{Ca}{\mathrm{F}}_2$ (111) and $\mathrm{Si}{\mathrm{O}}_2$ substrates were investigated. Film inhomogeneity and surface roughness were modeled by fitting ellipsometric data with an effective medium approximation, indicating a correlation between film inhomogeneity and surface roughness. The modeled surface roughness was compared with the atomic force microscope measurement. Film inhomogeneity was correlated to the cone-shaped columnar structure revealed by cross-sectional images from a scanning electron microscope. The film crystalline structure was determined by x-ray diffraction measurement, suggesting a different growth mechanism of $\mathrm{Gd}{\mathrm{F}}_3$ films on crystalline and amorphous substrates.

© 2008 Optical Society of America

Nanoporous structure of a GdF₃ thin film evaluated by variable angle spectroscopic ellipsometry

Jue Wang, Robert Maier, Paul G. Dewa, Horst Schreiber, Robert A. Bellman, and David Dawson Elli
Appl. Opt. 46(16) 3221-3226 (2007)

Crystal phase transition of HfO₂ films evaporated by plasma-ion-assisted deposition

Jue Wang, Robert L. Maier, and Horst Schreiber
Appl. Opt. 47(13) C189-C192 (2008)

Influence of substrate temperatures on the properties of GdF₃ thin films with quarter-wave thickness in the ultraviolet region

Jingcheng Jin, Chunshui Jin, Chun Li, Wenyuan Deng, and Shun Yao
Appl. Opt. 54(16) 5117-5122 (2015)

Microstructure-related properties at 193 nm of MgF₂ and GdF₃ films deposited by a resistive-heating boat

Ming-Chung Liu, Cheng-Chung Lee, Masaaki Kaneko, Kazuhide Nakahira, and Yuuichi Takano
Appl. Opt. 45(7) 1368-1374 (2006)

Optical and structural properties of LaF₃ thin films

Martin Bischoff, Dieter Gäbler, Norbert Kaiser, Andrey Chuvilin, Ute Kaiser, and Andreas Tünnermann
Appl. Opt. 47(13) C157-C161 (2008)