Modification on silicon (100) surfaces was demonstrated by using an atomic force microscope operating in air. Field-enhanced oxidation on silicon surfaces with protection oxide was done locally by biasing a p-type heavily doped silicon tip between −3 and −10 V. Oxide lines of width as small as ∼10 nm were achieved. After a dip in aqueous HF solution, the oxide was etched away; the modification depth, ∼1 nm, was characterized by the same atomic force microscope. Other field induced reactions for patterning are possible.

Nanometer structures were written on Si(100) surfaces by use of a non-contact-mode atomic force microscope. The silicon oxide was formed beneath the tip by applying a negative bias voltage between a p+ silicon tip and the samples. The writing resolution was mainly determined by the local chemical reactions induced by the tip and a minimum line width of about 10 nm was obtained, which is close to that achieved by scanning tunneling microscope and contact-mode atomic force microscope writing.