Study of ionic movements during anodic oxidation of nitrogen-implanted aluminium

In recent years there has been a considerable interest in synthetizing aluminium nitrides by ion implantation in order to modify the tribological properties of aluminium. The growth of an oxide layer by anodic process on these synthetized aluminium nitrides gives an interesting oxide-on-semiconductor material with surprising dynamic and decorative properties [1]. During the anodic oxidation, ionic movements are involved in the near-surface region of the aluminium material; these ionic movements have been studied by Rutherford backscattering spectrometry (RBS) and nuclear reaction analysis (NRA) on thin aluminium foils (7000 Å) preimplanted with nitrogen and post-oxidized in an ammonium pentaborate solution. The growth of the oxide layer is reduced when the aluminium is preimplanted with nitrogen: the speed of oxidation depends on the implantation conditions (energy and fluence). Moreover, the aluminium nitride can be dissolved when all metallic aluminium staying between the surface and the AlN are consumed by the anodic process.