Silicon that is nitrided in a pure nitrogen plasma is patterned with voltage applied by an atomic force microscope (AFM). Wet chemical etching into AFM-patterned (110) silicon produced vertical trenches as narrow as 91 nm (for one 757 nm deep trench) and with aspect ratios as large as 8.9:1 (for a 95 nm by 849 nm trench). Compared to the ridge patterns resulting from AFM oxidation and wet etching of hydrogen-passivated silicon, a substantially higher applied voltage is required to pattern nitrided silicon. (C) 2003 American Vacuum Society.