On the structural development during ultrathin amorphous Al sub(2)O sub(3) film growth on Al(111) and Al(100) surfaces by thermal oxidation

The structural developments during growth of ultrathin amorphous Al sub(2)O sub(3) film on bare Al(100) and Al(111) surfaces, by dry thermal oxidation in the oxygen partial pressure range of 1 x 10 super(-5)-1.0 Pa at 300 K, were investigated as function of the oxide-film thickness by (local) chemical state analysis using angle-resolved X-ray photoelectron spectroscopy in combination with low electron energy diffraction and cross-sectional high resolution transmission electron microscopy. The effect of the dielectric discontinuity, at the interfaces of the surficial Al sub(2)O sub(3) film has been determined quantitatively and has been subtracted from the observed chemical shifts of the core level photoelectron binding energies as well as from the observed Auger transition kinetic energies. It is revealed that ultrathin amorphous Al sub(2)O sub(3) films on the Al(111) and Al(100) surfaces experience remarkably different structural developments upon growth.