CVD of Lanthanum Oxyfluoride-Based Thin Films from a Lanthanum β-Diketonate Diglyme Precursor

Abstract

Lanthanum oxyfluoride-based thin films were grown on SiO2 and Si(100) by CVD from La(hfa)3*diglyme (Hhfa=1,1,1,5,5,5-hexafluoro-2,4-pentanedione; diglyme=bis(2-metoxyethyl)ether), acting both as lanthanum and fluorine source. Film syntheses were performed in nitrogen+wet oxygen atmosphere, with particular attention to the structural and compositional evolution as a function of the deposition temperature (200-500°C) and growth surface. To this aim, specimens were subjected to a multi-technique characterization by means of Glancing Incidence X-Ray Diffraction (GIXRD), X-ray Photoelectron Spectroscopy (XPS), Secondary Ion Mass Spectrometry (SIMS) and Atomic Force Microscopy (AFM). The formation of nanophasic (crystallite size <30 nm) LaOF-containing films, with a cleaner precursor conversion at the highest deposition temperatures, is evidenced and discussed, highlighting the most critical parameters for the obtainment of lanthanum oxyfluoride coatings with controlled properties.