EFFECT OF POLISHING ON FRACTURE STRENGTH OF FREE-STANDING CVD DIAMOND FILMS

The effect of polishing on fracture strength of free-standing CVD diamond films was investigated. Results indicate that the fracture strength of diamond films was reduced by the V shapes induced by the rough surface. The thicker the films were the more rapidly the fracture strength declined. Erasing the rough surface by polishing can improve the fracture strength of thick diamond films efficiently. An experimental calculation method was suggested,which can get the fracture strength of free-standing CVD diamond films closed to the essential strength.