Nanoscale Dot Patterning by Anodic Oxidation with Atomic Force Microscope

We report on nanoscale patterning by anodic oxidation in ambient using the atomic force microscope (AFM). Dot patterning on silicon and indium tin oxide (ITO) surfaces was achieved by applying a voltage pulse to induce surface oxidation. Oxide protrusions with size less than 100 nm have been created. The width of these oxide dots was found to vary slightly with the duration of the voltage pulse for both types of substrates. Meanwhile, the height of the dots exhibited a greater variation, particularly in the case of ITO, which may be linked to the surface roughness and the local material composition. A total patterning area of up to 100 times 100 mum² is achievable by programmed movements of the AFM tip. Such patterning, in combination with other processes such as metal deposition and etching, should prove a powerful tool for future applications in nanostructure fabrication and nanoscale electronics.