AVS 57th International Symposium & Exhibition
    Surface Science Wednesday Sessions
       Session SS1-WeM

Paper SS1-WeM10
Towards a Reliable Characterisation of Oxide Layers on Pure Aluminium using High Energy Resolution FE-AES

Wednesday, October 20, 2010, 11:00 am, Room Picuris

Session: Oxide Surface Structure
Presenter: T. Hauffman, Vrije Universiteit Brussel, Belgium
Authors: I. Vandendael, Vrije Universiteit Brussel, Belgium
T. Hauffman, Vrije Universiteit Brussel, Belgium
Y. Van Ingelgem, Vrije Universiteit Brussel, Belgium
A. Hubin, Vrije Universiteit Brussel, Belgium
H. Terryn, Vrije Universiteit Brussel, Belgium
Correspondent: Click to Email
Al2O3 on metallic aluminium is a widely used material of high technological importance. For the local chemical characterisation of these substrates FE-AES bears potential thanks to its high lateral resolution. In this study, the O KLL and Al KLL Auger electron spectral lines are recorded with a high energy resolution from pure aluminium, thin Al2O3 and thick Al2O3 layers on metallic aluminium. The behaviour of these aluminium oxide layers under electron beam irradiation is investigated.

It is demonstrated that, thanks to the high energy resolution used, it is possible to discriminate between the metallic and oxidised aluminium on the basis of the Al0 KL2,3L2,3 and Al3+ KL2,3L2,3 Auger electron peaks recorded within one and the same spectrum. Oxygen electron-stimulated desorption is observed for both aluminium oxides. Effective cross-sections for this oxygen desorption are estimated for the thin and thick oxide layers. It is shown that when an Al2O3 layer is irradiated with an electron beam surface charging occurs. These phenomena remain limited thanks to the presence of the underlying metallic aluminium substrate. The electron beam-induced effects are compensated by setting the angle of incidence of the primary electron beam to 15 °. Finally, it is shown that inhomogeneities at the surface of the analysed oxides result in significant chemical shifts of the O KLL and Al KLL Auger electron transitions. It is investigated whether these inhomogeneities can be linked with lateral differences in hydroxyl fraction at the surface.