Low‐power r.f. plasma oxidation of aluminium

Abstract

Valence-band and core-level XPS have been used to characterize the structure and growth of aluminium oxidized in a low-radiofrequency plasma. A change in the oxygen/aluminium ratio as a function of the metal substrate temperature during the plasma treatment correlated with changes in the valence band. Valence-band width and shape indicated that the films were characteristic of g-alumina. The change in shape of the high-binding-energy component of the band suggested that structural changes occurred to the film as a function of temperature. Plasma film growth could be described in terms of the Cabrera-Mott theory of field-assisted diffusion, with reaction velocities being higher than thermal oxidation rates reported in the literature. The reduction in the activation energy for plasma film growth was consistent with anion migration in a network-forming oxide.  For and on behalf of the Commonwealth of Australia

Interpretation of the Changing the Band Gap of Al2O3 Depending on Its Crystalline Form: Connection with Different Local Symmetries

“…One can allocate two main features A and B in the upper VB. According to calculations presented in ref , the band A originates predominantly from antibonding 2pπ states of the oxygen. The band B is assigned to the bonding 2pσ states of the oxygen mixed with 3s, 3p, and 3d states of aluminum in octahedral coordinated sites.…”

Study of oxidized layer formed on aluminium alloy by plasma oxidation

“…The Al 2p peak positions are all in a range of 74.9-75.0 eV. This binding energy is typical of aluminium in its oxidized form Al(3+) [1][2]4,7]. This means that aluminium atoms which are buried within 800 nm under surface completely react with oxygen to form Al 2 O 3 .…”

“…However, this oxide layer is too thin to prevent chloride ion from penetrating through oxide layer, pitting corrosion occurs easily in the sea water and saline water environment. Plasma oxidation may be used to produce thicker oxide layer on the surface of aluminium and its alloys [1][2][3]. By using plasma oxidation, Baier-Saip et al [4] obtained an oxide layer over 40 nm on aluminium surface.…”