Phase formation in double oxide films of Hf–La–O system

• Published in: Journal of crystal growth Vol. 377; pp. 212 - 216
• Main Authors: Smirnova, T.P., Yakovkina, L.V., Borisov, V.O.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-08-2013
• Subjects: A1. Solid solutions; A1. Structure; A1. X-ray diffraction; Atomic structure; Concentration (composition); Hafnium; Hafnium oxide; Hf1−xLaxOy films; Lanthanum; Solid solutions; X-ray photoelectron spectroscopy; X-rays; A1. Solid solutions; A1. Structure; A1. X-ray diffraction; Hf1−xLaxOy films
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2013.05.015

Metal Organic Chemical Vapor Deposition method (MO CVD) has been developed for LaxHf1−xOy films of an assigned composition by co-deposition from vapors of volatile La and Hf β-diketonates.
The phase composition and structure of films have been investigated by X-ray diffraction (XRD) (synchrotron radiation), Atomic Force Microscope (AFM), Energy Dispersive Spectroscopy (EDS), and X-ray Photoelectron Spectroscopy (XPS) methods.
It has been shown that the structure of films depends on lanthanum concentration. The formation of LaxHf1−xOy solid solution films of a cubic (fluorite-like) structure occurs with the lanthanum concentration extending from ∼4 to 18at% of.
The films comprising a mixture of monoclinic HfO2 (equilibrium) and cubic solid solution phases have been formed at CLa≤4at%. Two-phase films consisting of La2Hf2O7 (pyrochlore) and La2O3 (cubic) have been observed at lanthanum concentration (CLa)>25at%.
•The structure of LaxHf1−xOy solid solutions films produced by MO CVD depends on lanthanum concentration.•The films of fluorite-like structure occupy the area ∼4<CLa<12at%.•The films with 18at% La reveal the pyrochlore structure.•A mixture of monoclinic HfO2 and cubic solid solution phases were formed at CLa≤4at%.•Two-phase films consisting of La2Hf2O7 (pyrochlore) and La2O3 (cubic) were observed at CLa>25at%.