Spectroscopic Characterization of Thermostimulated Transformation of Thin Films Based on Transition Metal Oxides Doped with Germanium

This work investigates the influence of germanium (Ge) doping on the structural properties of complex oxide films based on tantalum-zirconium oxide (TaZrO<inf>x</inf>) with a comparative analysis including Ge-doped ZrO<inf>2</inf> films and their undoped counterparts. The thin films were deposited by magnetron sputtering and subjected to post-deposition annealing at 300-1000 °C in a nitrogen atmosphere. Fourier-transform infrared (FTIR) spectroscopy was employed to monitor changes in the vibrational modes associated with metal-oxygen bonding upon Ge incorporation. Shifts in the stretching modes, particularly within the 400-1000 cm^-1 range, indicate site-selective incorporation of Ge into the Zr or Ta sublattices, modifying the local coordination and bonding environment. Comparative analysis suggests that Ge preferentially substitutes for Zr rather than Ta, consistent with thermodynamic trends in bond enthalpies and ionic radii. The results highlight the sensitivity of FTIR spectra to compositional variations in multi-cation oxide systems and provide insights into the structural role of Ge in modulating the vibrational and potentially functional properties of TaZrO<inf>x</inf>-based films. These findings support the potential of Ge doping as a tunable parameter for tailoring the dielectric and optical properties of high-k complex oxides.