Method for fabricating micro/nanostructures via scanning probe microscope and anisotropic wet etching

The direct modification of silicon, other semiconductors and metal surfaces by the process of local anodic oxidation via electric field from scanning probe microscope (SPM) in conjunction with the absorbed water in atmosphere as the electrolyte is a promising method for fabricating micro/nanostructures. We demonstrated that the process of SPM oxidation and anisotropic wet chemical etching is a low cost and reliable method to produce smooth and uniform etched structures on silicon substrates. Using silicon oxide nanopatterns produced on H-passivated (110) Si surfaces as etching masks, and due to the large (110)/(111) anisotropic ratio of etching rate and the large Si/SiO2 etching selectivity at a relatively low etching temperature and an optimal concentration of aqueous KOH etchant, high-aspect-ratio grating structures have been fabricated by anisotropic wet etching. The approach of combining scanning probe lithography (SPL) with etching technique provides an alternative lithography route to fabricate functional nanophotonic or nanoelectronic devices.