Properties of TiO2 films prepared by ion-assisted deposition using a gridless end-Hall ion source

TiO2 thin films were deposited using electron-beam gun evaporation with ion-assisted deposition (IAD) of low energy oxygen ions from an end-Hall ion source. The index of refraction and stress were measured as a function of the ion source voltage and current and were compared with results without IAD. The index of refraction increased with the increase of the ion gun voltage. The stress changed from compressive to tensile with the voltage increase, resulting in a better performance than conventional thermal evaporation. Atomic force microscopy was used to study the microstructure of the films. Quantitative roughness measurements of the surface showed that the roughness of the IAD films was smaller than that of layers without IAD.