Method for forming a surface-roughened conductive film on a semiconductor wafer

A method for forming a surface-roughened conductive film on a semiconductor wafer comprising the steps of:

• subjecting an amorphous silicon conductive film formed on said semiconductor wafer to treatment with hydrofluoric acid to remove a natural oxide film therefrom;
• forming a very thin oxide film having a thickness ranging from 0.5 angstroms to 20 angstroms on the conductive film following said treatment with hydrofluoric acid, by a method selected from the group consisting of treatment with an aqueous hydrogen peroxide solution, flushing treatment with an oxidizer, standing in a clean room, and rinsing by clean water;
• forming a nucleating film on said very thin oxide film by use of a silane gas;
• and
• annealing said wafer having said nucleating film to roughen the surface of said conductive film.