Titanium dioxide films are highly resistive to mechanical friction as well as stable to chemical reaction and have a fairly high refractive index in the visible and infra-red regions. These properties have resulted in titanium dioxide films being used for optical thin films.
Titanium dioxide, however, loses oxygen rather easily when it is heated in vacuum. Therefore it is usually difficult to obtain stoichiometric TiO
2 thin films.
In this paper, the evaporation were performed under the pressure from 2 × 10
-4 to 5 × 10
-5 Torr by electronbeam-system.
Changing the substrate temperature, the film thickness and the deposition rate, chemical composition and refractive index of the films were studied.
In the X-ray diffraction analysis, it was found that the films were Anatase-type TiO
2 when the substrate temperature were raised higher than 120°C, i.e. there was the critical temperature at 120°C from Amorphous to Anatase-type titanium oxide.
At high deposition rate there deposited simultaneously Rutile-type TiO
2 and Anosovite Ti
3O
5 (Ti
2O
3· TiO
2).
The refractive indices of Anatase and Amorphous films were obtained 2.4 and 2.15 respectively at 600 mμ.
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