ROUGHNESS REDUCTION METHODS FOR MATERIALS USING ILLUMINATED ETCH SOLUTIONS

Methods are disclosed that illuminate etch solutions to provide controlled etching of materials. An etch solution (e.g., gaseous, liquid, or combination thereof) with a first level of reactants is applied to the surface of a material to be etched. The etch solution is illuminated to cause the etch solution to have a second level of reactants that is greater than the first level. The surface of the material is modified (e.g., oxidized) with the illuminated etch solution, and the modified layer of material is removed. The exposing and removing can be repeated or cycled to etch the material. Further, for oxidation/dissolution embodiments the oxidation and dissolution can occur simultaneously, and the oxidation rate can be greater than the dissolution rate. The material can be a polycrystalline material, a polycrystalline metal, and/or other material. One etch solution can include hydrogen peroxide that is illuminated to form hydroxyl radicals.