Nanocrystalline Lanthanum Oxyfluoride Thin Films by XPS

Abstract

Nanocrystalline lanthanum oxyfluoride thin films were synthesized by chemical vapor deposition (CVD) using La(hfa)3⋅diglyme (hfa=1,1,1,5,5,5-hexafluoro-2,4-pentanedionate; diglyme=bis(2-metoxyethyl)ether) as precursor compound. The coatings were deposited on Si(100) and commercial silica slides in nitrogen+wet oxygen atmospheres, at temperatures between 200 and 500 °C, with particular attention to the structural and compositional evolution as a function of the synthesis conditions and growth surface. The obtained samples were characterized by glancing-incidence x-ray diffraction (GIXRD), secondary ion mass spectrometry (SIMS), x-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM), for a detailed determination of their microstructure, chemical composition, and surface morphology. This work is dedicated to the XPS characterization of a representative LaOF thin film deposited on Si(100) at 500 °C. Besides the wide scan spectrum, detailed spectra for the La 3d, F 1s, O 1s, and C 1s regions and related data are presented and discussed. Both the F/La atomic ratio and La 3d peak shape and position point to the formation of stoichiometric LaOF thin films. Moreover, carbon contamination was merely limited to the outermost sample layers.