Tailoring the composition and deposition kinetics of RF-sputtered BaTiO3 thin films through working pressure and target-substrate distance adjustments

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Optimizing the growth of BaTiO 3 thin films is essential for operating their ferroelectric and dielectric properties for embedded microelectronic applications. The present study investigates in a combinatorial-like approach the deposition of BaTiO 3 thin films by radiofrequency magnetron sputtering on SiO 2 /Si substrates under various working pressures (1 to 6 Pa) and target-substrate distances (7.5 to 9.2 cm). X-ray diffraction (XRD), Atomic Force Microscopy (AFM) and Rutherford Backscattering Spectroscopy (RBS) characterizations were used to establish the relationships between the sputtering deposition parameters and the resulting deposition rates, crystalline quality, surface roughness, and stoichiometry of the BaTiO 3 thin films. Low pressures and short distances lead to high kinetic growth of amorphous Ba-deficient films. Increasing working pressure × target-substrate distance values above 0.30 Pa.m enables to attain the stoichiometric Ba/Ti ratio. This result is related to both Ba and Ti species thermalization into the plasma leading to improve the chemical composition of the films. Furthermore, crystalline quality of the BaTiO 3 films is improved by reducing the deposition rate through working pressure and target-substrate distance adjustment. These results can provide valuable roadmaps to set BaTiO 3 sputtering parameters for high-quality thin films deposition based on the stoichiometry balance and deposition kinetics, that can be further extended to other perovskite compounds.

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