The laser-arc: a new industrial technology for effective deposition of hard amorphous carbon films

The laser-arc evaporation process has been developed to an industrial high rate deposition technology for amorphous carbon films of diamond-like nature. Deposition rates above 3 nm s(exp-1) have been realized on substrates larger than 100 cm2 with the quality being comparable with magnetically filtered arc techniques characterized by a much lower efficiency. The basic process consists of a pulsed cathodic vacuum arc ignited by focused laser pulses. By limiting the arc pulse duration between 20 and 100 mu m the arc spot erodes only a definite region surrounding it's ignition point, the laser focus. Thus, the local overheating of the cathode material and the emission of microparticles, the inherent drawback of the conventional process, are essentially reduced. The arc spot position is controlled by the displacement (scanning) of the laser focus on the rotating cylindrical cathode, allowing it's systematic erosion. With cathodes composed of different materials, multilayered film structure s can be realized with easily changed variations. Owing to the low deposition temperature, below 150 deg C, the method is especially suitable for temperature-sensitive substrate materials. Examples for the applications of laser-arc coatings in different fields are presented.