Abstract

${\mathrm{HfO}}_2$ is a well-known high-refractive-index material for optical interference coatings from the infrared down to the ultraviolet (UV). Dense, homogeneous, and stoichiometric ${\mathrm{HfO}}_2$ film is critical for low-loss UV optics where the spectral region is close to its fundamental absorption edge. We prepare ${\mathrm{HfO}}_2$ films by plasma-ion-assisted deposition with various amounts of plasma-ion momentum transfer. The correlation between the ${\mathrm{HfO}}_2$ film structure and the optical properties are evaluated by a variable-angle spectroscopic ellipsometry, indicating inhomogeneous to homogeneous to inhomogeneous film structural evolution with increasing momentum transfer during deposition. The ${\mathrm{HfO}}_2$ film inhomogeneity, surface roughness, and crystal phase are confirmed by scanning electron microscopy cross-sectional, atomic force microscopy, and x-ray diffraction measurements. The results suggest that the ${\mathrm{HfO}}_2$ film structural evolution corresponds to crystal phase transition from weak monocline amorphous to strong monocline depending on the amount of plasma-ion momentum transfer during film deposition.

© 2008 Optical Society of America

Effects of annealing on the optical, structural, and chemical properties of TiO₂ and MgF₂ thin films prepared by plasma ion-assisted deposition

Seouk-Hoon Woo and Chang Kwon Hwangbo
Appl. Opt. 45(7) 1447-1455 (2006)

Structural comparison of GdF₃ films grown on CaF₂ (111) and SiO₂ substrates

Jue Wang, Horst Schreiber, Ronald W. Davis, and Bryan R. Wheaton
Appl. Opt. 47(23) 4292-4296 (2008)

Optical inhomogeneity and microstructure of ZrO₂ thin films prepared by ion-assisted deposition

Hyun Ju Cho and Chang Kwon Hwangbo
Appl. Opt. 35(28) 5545-5552 (1996)

Elastic and plastic relaxation of densified SiO₂ films

Jue Wang, Robert L. Maier, and Horst Schreiber
Appl. Opt. 47(13) C131-C134 (2008)

Wavefront control of SiO₂-based ultraviolet narrow-bandpass filters prepared by plasma ion-assisted deposition

Jue Wang, Robert L. Maier, and Horst Schreiber
Appl. Opt. 46(2) 175-179 (2007)