Y. Leprince-wang et al., Relations between the optical properties and the microstructure of TiO2 thin films prepared by ion-assisted deposition, THIN SOL FI, 359(2), 2000, pp. 171-176
Oxygen ion-assisted TiO2 thin films have been studied by il I situ visible
spectroscopic ellipsometry (SE) and transmission electron microscopy (TEM).
Influence of the substrate nature and the substrate temperature, the ion k
inetic energy E-c and the ion/molecule ratio Phi(i)/Phi(at) was investigate
d on the microstructure and the optical properties of the films. It is reve
aled that the refractive index n varies as a function of the average energy
per TiO2 molecule, E-d = E-c(Phi(i)/Phi(at)). Conditions for obtaining den
se films with a high refractive index (n similar to 2.60 at lambda = 0.45 m
u m) and a low extinction coefficient k have been found for E-d > E-dth (E(
dth)similar to 50 eV). These dense films are insensitive to moisture adsorp
tion with a low surface roughness. Cross-sectional TEM has been mainly used
for microstructure observation and phase identification of the films prepa
red under different evaporation conditions. Comparison is done in relations
hip with the optical property measurements. (C) 2000 Elsevier Science S.A.
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