Impact of lanthanum on the modification of HfO sub(2) films structure

• Published in: Journal of rare earths Vol. 33; no. 8; pp. 857 - 862
• Main Authors: Smirnova, T P, Yakovkina, L V, Borisov, V O
• Format: Journal Article
• Language: English
• Published: 01-08-2015
• Subjects: Concentration (composition); Film thickness; Grazing incidence; Hafnium oxide; Phases; Rare earth metals; X-ray photoelectron spectroscopy; X-rays
• ISSN: 1002-0721
• DOI: 10.1016/S1002-0721(14)60496-8

La sub(x)Hf sub(1-x)O sub(y) thin films with various concentrations of La, homogeneous and nonhomogeneous distributions of elements throughout the films thickness was purposefully grown by CVD. The composition of the films and their chemical structures were characterized throughout the films thickness by X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray spectrometry (EDXA). A full picture of the film crystallinity was provided by the combination of grazing incidence X-ray diffraction (GIXRD) synchrotron radiation (SR) and high resolution transmission electron microscopy (HR TEM). It was shown that La acted as "molar volume modulator" and stabilized the nonequilibrium at T[< or =]1300 [degrees]C cubic phases. The samples with La content in range of 7 at.%<C sub(La)<22 at.% were materials with fluorite-type (Fm-3m) structure. The pyrochlore phase formation was observed at ~18 at.% La content. The correlation between the La-doped content and the films microstructure was revealed.