In this work we have investigated the effect of MeV heavy ion irradiation on titanium dioxide (TiO₂) thin films using Time-of-Flight Elastic Recoil Detection Analysis (ToF-ERDA). The studied TiO₂ were grown by reactive DC magnetron sputtering yielding polycrystalline films having a dense columnar structure. During the ERD analysis a clear decrease in areal atomic concentrations of Ti and O was observed, however, the stoichiometry remained essentially constant up to the highest applied fluence. This change in areal atomic concentration with increasing ion fluence is partly attributed to electronic sputtering.

To investigate the change in areal concentration in more detail, samples were irradiated at RT with different MeV heavy ions, applying ion fluences in the range 10¹⁰ to 10¹⁴ ions/cm². X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) were used to characterize the films prior to and after the ion irradiation.

Distinct morphological and structural changes of the film were observed with increasing fluence, which extended through the whole film. XRD revealed that the crystallinity of the film was gradually destroyed, leading to amorphous films above 5×10¹² ions/cm². SEM and AFM measurements showed topographical changes in the form of surface recession and smoothing compared to the pristine polycrystalline surface. The film thickness decreased with up to 20% for the maximum applied fluence. In addition to surface smoothing, the columnar structure was also partly erased. The possible damage mechanisms responsible for the observed film modifications will be discussed and related to the ERD measurements.