total ion current from each of the plate shaped targets in one embodiment of the invention the sum of total ion currents from a respective plate shaped target divided by the volume of the vacuum chamber is at least 3 a m 3 preferably the arc current is a direct current supplied by a power supply connected to the deposition system the direct current is not necessarily constant over time although the arc current may show considerable variation during deposition due to individual contribution from the short lived arc discharges this direct current should not be mixed up with pulsed deposition techniques pulsed deposition can be used for the same reasons as in prior art deposition processes in one embodiment of the method of invention the impedance which is determined by measuring the average voltage and arc current over the anode arrangement and the plate shaped target is controlled to be within a predetermined range preferably less than 0 1 ohm more preferably less than 0 05 ohm during deposition such that the arc plasma is almost uncontrolled this is accomplished at least partly by using a comparatively weak lateral magnetic field for steering the arc discharge contrary to steered arc techniques where a strong magnetic field is used these steered arc techniques are one conventional way to increase the arc.