Fabrication of Si nanostructures with an atomic force microscope

A method for fabricating Si nanostructures with an air-operated atomic force microscope (AFM) is presented. An electrically conducting AFM tip is used to oxidize regions of size 10–30 nm of a H-passivated Si (100) surface at write speeds up to 1 mm/s. This oxide serves as an effective mask for pattern transfer into the substrate by selective liquid etching. The initial oxide growth rate depends exponentially on the applied voltage which produces an effective ‘‘tip sharpening’’ that allows small features to be produced by a relatively large diameter tip.