Thickness determination of anodic titanium oxide films by electron probe microanalysis

Thin film thickness can be readily associated to the X-ray intensities emitted under electron bombardment. The aim of this work is to develop a method for measuring titanium oxide thicknesses in biomaterials from the X-ray spectra induced in a scanning electron microscope. The oxide layers studied were generated with different anodizing voltages applied in phosphoric and boric acid solution (H3PO4/H3BO3). The oxygen Kα intensity was registered for each sample and related to the corresponding thickness. In order to account for local material alterations, a recalibration is shown to be necessary; Rutherford backscattering spectroscopy was used at this stage. The method is useful for TiO2 thicknesses in the range of interest for dental and orthopedic implants (10-100 nm), and it could be extended to greater thicknesses by adequately selecting the electron beam energy.