Minimization of the arc energy in hipims
The high power density in HIPIMS increases the probability of arcs on the target surface and complicates the arc suppression problem, compared to the conventional direct current and mid-frequency magnetron sputtering. The output inductance stores a large amount of residual energy, which is transferred to the arc after turning off the control transistor and can cause the formation of microdroplets. In this work the HIPIMS power supplies are compared, in terms of the amount of energy transferred to the arc. It is shown that if the response time of a power source is less than 1 μs, the arc energy consists almost entirely of the residual energy stored in the output inductance of the power supply and the cable. Depending on the parameters of the scheme and the setting of the protection system, the detection of the arc by voltage makes it possible to reduce the arc burning energy by 1.5-2 times, with respect to the detection of the arc by current. To reduce the arc energy to lower values, the residual energy must be reduced. It was demonstrated that the scheme with the topology of a single-ended forward bridge converter provides for the recovery of residual energy, which under certain experimental conditions allowed to reduce the arc energy fourfold from 175 to 42 mJ.