Spectral ellipsometric TEM and electron spectroscopic investigations on oxidized aluminium thin films

Abstract

Abstract Previous spectral and multiple angle of incidence ellipsometry on aluminium thin films has been extended to Λ=633 nm and thick oxide films. The optical constants of a highly perfect Al thin film resulted in n=1.42 andk=7.30 for 633 nm. The thickness and refractive index of thick (thermal and anodic) oxide films have been determined by computer optimization of ellipsometric experimental data. The microstructure of the Al substrate can produce uncertainties in the ellipsometric determination of oxide overlayer thickness. The thickness of oxide film has been determined by high resolution TEM on cross-sectional samples of SiAloxideAl structures and resulted in good agreement with previous results. The 3rd and 4th plasmon loss peaks in the reflection electron energy loss and elastic peak spectra revealed considerable differences between the Al2O3|Al and Al samples, enabling an estimation of oxide layer thickness.