Use of ion implantation in chemical etching

A method for controlling chemical dry etching to improve smoothness of an etched surface, comprising:

• a) implanting ions into a surface to form a volatilizable compound at a temperature low enough to avoid, reduce, or eliminate formation of three-dimensional structures of the volatilizable compound that might create the roughness at an etched surface of the volatilizable compound, wherein the ions are applied in a sufficient energy to penetrate to a predetermined depth of material that is to be removed from the surface in an etching cycle, and in a sufficient dosage to achieve full formation of the volatilizable compound;
• b) exposing the surface of the volatilizable compound to a gas composition for a time duration sufficient to completely etch the volatilizable compound;
• and
• c) rotating the surface while implanting the ions into the surface to form the volatilizable compound, wherein rotating the surface includes imparting planetary motion to the surface;
• wherein the ions are implanted at a glancing-angle of incidence of about 15° to 45° relative to a plane of the surface.