Laser-Arc - ein neuartiges Verfahren der lasergestützten Vakuumbogenbeschichtung

The laser-arc evaporation, a PVD process taking place in a vacuum atmosphere of 10 (exp -3) Pa, is characterised by application of a pulse laser for the ignition and controlling of the arc spot motion on the cathode surface. By limitation of the arc pulse duration the arc spot erodes a definitely region surrounding its ignition point, the laser focus. The linear oscillation of laser beam and linear moving of the cathode, preferable the rotation of as roll formed cathode, allows a systematically erosion of the cathode surface. The arc burning limitation reduces the overheating and melting of the cathode material and on this way the emission of macroparticles, a disadvantages of the conventional arc processes. By application of a cathode, compound of different materials, a deposition of multilayered film structures is realised. The laser-arc evaporation is a high rate deposition process. Deposition rates above 10 gm per hour are obtained by using a peak arc current of 1 kA, pulse duratio n between 20 and 100 microseconds and repetition frequency up to 1 kHz. The deposition can be carried out in a residual gas atmosphere in the chamber. The arc induces plasma is nearly completely ionised. By application of carbon as cathode material the plasma is characterised by single charged carbon ions with a kinetic energy above 20 eV. Therefore, it can be deposited amorphous carbon films with diamond-like properties on different substrate materials (Si, Al, Al-alloys, Cu, steel etc.) with a high adherence. An advantage is that the deposition is carried out at temperatures below 150 Cel and especially temperature sensitive materials can be coated