Carbonaceous alumina films deposited by MOCVD from aluminium acetylacetonate: a spectroscopic ellipsometry study

Spectroscopic ellipsometry was used to characterize carbonaceous, crystalline aluminium oxide films grown on Si(100) by low-pressure metal organic chemical vapour deposition, using aluminium acetylacetonate as the precursor. The presence of carbon in the films, attributed to the use of a metalorganic precursor for the deposition of films, was identified and analysed by secondary ion mass spectroscopy and X-ray photoelectron spectroscopy, for the elemental distribution and the chemical nature of the carbon in the films, respectively. Ellipsometry measurements over the photon energy range 1.5-5 eV were used to derive the pseudo-dielectric function of the aluminium oxide-containing films. Multi-layer modelling using linear regression techniques and the effective medium approximation were carried out to extract the structural details of the specimens. The excellent fit between the simulated and experimental optical data validates the empirical model for alumina-containing coatings grown by MOCVD.