Interface Induced Diffusion; Area Selective Interface Patterning

Interface induced diffusion had been identified in thin film system damaged by electron bombardment. This new phenomenon was observed in Al 2 O 3 (some nm thick) / Si substrate system, which was subjected to low energy (5 keV) electron bombardment producing defects in the Al 2 O 3 layer. The defects produced partially relaxed. The rate of relaxation is, however, different in the surrounding of the interface and in the "bulk" parts of the Al 2 O 3 layer. This difference generates an oxygen concentration gradient and consequently oxygen diffusion, resulting in an altered layer which grows from the Al 2 O 3 / Si substrate interface. The relative rate of the diffusion and relaxation is strongly temperature dependent, resulting in various altered layer compositions, SiO 2 (at room temperature), Al 2 O 3  + AlO x +Si (at 500 o C), Si(at 700 o C), as the temperature during irradiation varies. Utilizing this finding it is possible to make area selective interface patterning.