Interface induced diffusion

Interface induced diffusion had been identified in a thin film system damaged by electron bombardment. This new phenomenon was observed in Al₂O₃ (some nm thick)/Si substrate system, which was subjected to low energy (5 keV) electron bombardment producing defects in the Al₂O₃ layer. The defects produced partially relaxed. The rate of relaxation is, however, was different in the vicinity of the interface and in the "bulk" parts of the Al₂O₃ layer. This difference creates an oxygen concentration gradient and consequently oxygen diffusion, resulting in an altered layer which grows from the Al₂O₃/Si substrate interface. The relative rate of the diffusion and relaxation is strongly temperature dependent, resulting in various altered layer compositions, SiO₂ (at room temperature), Al₂O₃ + AlO_x + Si (at 500 °C), Al₂O₃ + Si (at 700 °C), as the temperature during irradiation varies. Utilizing this finding it is possible to produce area selective interface patterning.