Negative tone patterns were created by polymer-contamination writing in a transmission electron. microscope. Typical line edge roughness of the polymer lines was found to be below 1 nm. The patterns were transferred to bismuth films using an anisotropic ion etch, resulting in final bismuth line edge roughness less than 2 nm. This low roughness was achieved by growing the bismuth film such that the same crystallographic planes were exposed to the etching flux of ions. (C) 2005 American Vacuum Society.