Structure of glancing incidence deposited TiO2 thin films as revealed by grazing incidence small-angle x-ray scattering

Abstract

For the first time, grazing incidence small-angle X-ray scattering (GISAXS) analysis is used to characterize the morphology of TiO2 thin films grown by glancing angle physical vapor deposition (GLAD). According to cross-section scanning electron microscopy (SEM) images, the films consist of near isotilted TiO2 columns of different length and width depending on film thickness. The obtained GISAXS patterns show a characteristic asymmetry with respect to the incidence plane, which is associated with the tilted geometry of the TiO2 columns. The patterns also show the existence of two populations of columns in these GLAD-TiO2 films. The population of the thinnest columns appears related to the first grown layer and is common for all the films investigated, while the second population of columns grows with the thickness of the films and has been related to wider columns formed by shadowing at the expense of the initially formed columns. © 2010 Wiley-VCH Verlag GmbH& Co. KGaA, Weinheim.