Effect of ion assisted deposition on optical scatter and surface microstructure of thin films

Abstract

Ion bombardment of a film during deposition has pronounced effects on the electrical, mechanical, and optical properties of the film. One important optical property is the optical scatter characteristic of the film. This is determined by the film surface and volume microstructure, and thus can be used as a convenient diagnostic technique to examine film morphology. We have examined these effects for metal (Cu and Mo) and dielectric (SiO2 and TiO2) films. We observe, for example, a significant reduction in optical scatter due to surface structure of period <3 μm in the case of films deposited with simultaneous ion bombardment. Other experimental data and a simple model to explain this possible smoothing effect are presented.