Ion current-adapted control of the arc current in a pulsed cathodic arc process

As shown in previous publications concerning cathodic arc deposition, the vacuum arc as a technological tool can be very complexly influenced by variation of the electrical arc parameters. The pulsed arc current and the resulting ion current influence the formation of the coating. To determine optimised parameters for the deposition process, the dependence on the frequency, on the rate of current rise and on the maximum pulse current in particular were investigated. Using the variation of the output parameters of a pulsed arc power supply, the ion current was steered in its shape and its absolute values. Therefore, the shape of arc current pulses was varied, especially in the phase of rise and fall (triangle, sine, rectangle). Among other things, it was noted that at the beginning of the pulse an excessive increase in ion current is measurable. In order to use this increase for a more effective coating process, experiments were carried out using pulses with controlled slopes and current levels or double pulses of rectangular shape. The examinations have shown that an increase in the ion current ratio in the arc current can be reached by a suitable choice of the electrical parameters. The plasma can be controlled by the electrical parameters of the current source.