A technique is presented for fabricating Si nanostructures with a scan
ning tunneling microscope operated in air. The process involves the di
rect chemical modification of a H-passivated Si(100) surface and a sub
sequent liquid etch. The chemically modified portions of the surface c
an 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 mum/s, large-area (50 mum X 50 mum) patterns with lateral featu
re sizes approximately 25 nm are reliably fabricated.