부산대학교 도서관

This work reports the impact of Yb content on the structural and ferroelectric properties of the BiFeO3 thin films fabricated on the Pt/TiN/Si substrates by dc and rf cosputtering. The Yb-doped BiFeO3 thin films were prepared under three different Yb plasma powers (10 W, 11 W, 12 W). X-ray diffraction demonstrated that the Yb-doped BiFeO3 thin films showed the distortion of rhombohedral structure. Scanning electron microscopy indicated that the Yb-doped BiFeO3 thin film prepared at the 11 W condition exhibited smaller grain sizes than those of the other conditions. Atomic force microscopy revealed that the Yb-doped BiFeO3 thin film treated at the 11 W condition featured a lower surface roughness compared with the other conditions. Secondary ion mass spectrometry manifested that the Yb-doped BiFeO3 film showed the sharp compositional profiles near the BiFeO3/Pt interface. Moreover, X-ray photoelectron spectroscopy signified that the Yb-doped BiFeO3 film fabricated at the 11 W condition possessed a higher Fe3+/Fe2+ concentration ratio and a lower intensity of oxygen vacancies than the other conditions. Among these conditions, the BiFeO3 thin film fabricated at the 11 W condition exhibited the lowest leakage current of 1.71 × 10–5 A/cm2 at an electric field of 200 kV/cm and the highest remnant polarization of 61.7 μC/cm2. [ABSTRACT FROM AUTHOR]