LASER-ASSISTED ETCHING OF DIAMONDS IN AIR AND IN LIQUID-MEDIA

Etching of both synthetic diamond monocrystals and diamond polycrystal line films has been studied with the help of a copper vapor laser (wav elength of 510 nm, pulse duration of 10 ns, pulse repetition rate of 8 kHz) in various surrounding media (air, H2O, DMSO). Diamond samples a re virtually transparent in this wavelength and the coupling of laser radiation to diamond is due to the formation of a thin graphitized lay er at the diamond surface. The etching rate in liquid media is slightl y higher than in air, at otherwise equal conditions, and is as high as 50 mu m s(-1) under the etching with a scanning laser beam. Raman spe ctra measurements carried out on diamond samples etched in air show th e presence of glassy carbon on the surface, while under the etching in a liquid the diamond peaks at 1332 cm(-1) and dominates with signific antly lower intensity of the glassy carbon peak. Electroless copper de position on the laser-etched features was studied to compare the catal ytic activity of the diamond surface etched in air with the catalytic activity of the surface irradiated in liquids. Possible mechanisms res ponsible for the observed difference both in the structure of the etch ed area and in the electroless Cu deposition onto the surface etched i n various media (air or liquids) are discussed. (C) 1997 Published by Elsevier Science S.A.