LASER POLISHING OF EXTENDED DIAMOND FILMS

Diamond films are polished using an ArF laser at 193 nm wavelength and a pulse duration of 20 ns. Flat areas are scanned by the laser beam a t incident angles of 80 degrees and 85 degrees. Different combinations of scanning and stepwise rotation are applied in order to achieve irr adiation from different directions. Irradiating the film from at least three directions prevents increased roughness due to rippling and the refore results in a lower roughness than irradiating from just one or two sides. The average roughness reaches a minimum after the optimum p olishing time and then increases again with further treatment. The unt reated diamond film shows a roughness of 153 nm as measured using a pr ofilometer. With laser polishing, the best values are reduced to 22 nm for an incident angle alpha of 85 degrees and to 42 nm for alpha = 80 degrees.