Role of Buffer Layers in Defect Chemistry and Parasitic Phase Formation of BiFeO3 Films on Silicon

Role of Buffer Layers in Defect Chemistry and Parasitic Phase Formation of BiFeO3 Films on Silicon

Článek WoS

Achieving the reliable integration of bismuth ferrite with silicon requires precise control over phase formation, cation stoichiometry, and near-surface oxygen chemistry. In this study, BiFeO3 films were deposited by pulsed laser deposition onto Ti- and TiO2-buffered Si substrates under varied oxygen partial pressures and substrate temperatures. Structural, morphological, and chemical evolutions were investigated using X-ray diffraction, scanning electron microscopy, and combined survey and high-resolution X-ray photoelectron spectroscopy. Both buffer types yield polycrystalline BiFeO3 films; Ti-buffered samples exhibit lower variations in Bi/Fe surface ratios, whereas TiO2buffered films show a reduced contribution from hydroxyl-related oxygen species at the surface. X-ray photoelectron spectroscopy confirms that Bi and Fe remain exclusively in the trivalent state under all growth conditions. High-resolution oxygen spectra demonstrate that oxygen chemistry is the most sensitive indicator of near-surface disorder, reflecting contributions from lattice oxygen and surface hydroxylation arising from ambient exposure. Minor Bi2O3 phases persist across the investigated deposition window; however, their evolution, together with surface oxygen trends, indicates that intermediate-to-high substrate temperatures combined with moderate-to-low oxygen pressures provide the most favorable conditions for stabilizing near-stoichiometric BiFeO3. Overall, the results highlight oxide buffer layers as effective regulators of surface chemistry, enabling a scalable route for integrating BiFeO3 films on silicon.

Achieving the reliable integration of bismuth ferrite with silicon requires precise control over phase formation, cation stoichiometry, and near-surface oxygen chemistry. In this study, BiFeO3 films were deposited by pulsed laser deposition onto Ti- and TiO2-buffered Si substrates under varied oxygen partial pressures and substrate temperatures. Structural, morphological, and chemical evolutions were investigated using X-ray diffraction, scanning electron microscopy, and combined survey and high-resolution X-ray photoelectron spectroscopy. Both buffer types yield polycrystalline BiFeO3 films; Ti-buffered samples exhibit lower variations in Bi/Fe surface ratios, whereas TiO2buffered films show a reduced contribution from hydroxyl-related oxygen species at the surface. X-ray photoelectron spectroscopy confirms that Bi and Fe remain exclusively in the trivalent state under all growth conditions. High-resolution oxygen spectra demonstrate that oxygen chemistry is the most sensitive indicator of near-surface disorder, reflecting contributions from lattice oxygen and surface hydroxylation arising from ambient exposure. Minor Bi2O3 phases persist across the investigated deposition window; however, their evolution, together with surface oxygen trends, indicates that intermediate-to-high substrate temperatures combined with moderate-to-low oxygen pressures provide the most favorable conditions for stabilizing near-stoichiometric BiFeO3. Overall, the results highlight oxide buffer layers as effective regulators of surface chemistry, enabling a scalable route for integrating BiFeO3 films on silicon.

Bismuth ferrice, oxides, oxygen, thin films, XPS

Bismuth ferrice, oxides, oxygen, thin films, XPS

FAWAEER, S.; AL-QAISI, W.; SEDLÁKOVÁ, V.; MOUSA, M.; KNÁPEK, A.; SOBOLA, D.

13.02.2026

Amer Chemical Soc

ACS Omega

11

5

Spojené státy americké

7782

7795

14

https://pubs.acs.org/doi/10.1021/acsomega.5c08852