Fabrication of silicon nanostructures with a scanning tunneling microscope

A technique is presented for fabricating Si nanostructures with a scanning tunneling microscope operated in air. The process involves the direct chemical modification of a H-passivated Si(100) surface and a subsequent liquid etch. The chemically modified portions of the surface can withstand a deep (≳100 nm) liquid etch of the unmodified regions with no etch degradation of the modified surface. At a write speed of 1–10 μm/s, large-area (50 μm×50 μm) patterns with lateral feature sizes ∼25 nm are reliably fabricated.