A method is described which permits rapid and precise selective etching of silicon crystal surfaces without protecting any part of the surface during the etch procedure. Prior to the etching process the areas to be etched are subjected to an ion‐bombardment treatment, which increases the etch rate in the bombarded surface layer compared to the etch rate of untreated silicon. Etching characteristics for silicon crystals bombarded with neon and argon are presented and shown to agree with theoretical predictions based on a simple model in which the etching characteristics are related to implantation‐produced cluster damage.