Effect of self-bias on transport of vacuum arc plasmas through magnetic filters

Summary form only given, as follows. Curved magnetic filters are commonly used with cathodic vacuum arcs to remove macroparticles from the plasma stream. Such filtering is necessary for high quality of coatings for semiconductor and optical applications. It is known that biasing the filter positively improves plasma throughput and thus deposition rate. For systems operating with pulsed arcs and open filters, it is practical and economical to use the arc current for generation of magnetic filter field. This approach eliminates the need for a magnet supply and also reduces the overall power consumption and cooling needs. This solution has the additional advantage that higher currents can be utilized than one would use for DC systems, and higher currents can be advantageous for obtaining highest system coefficients. There was, however, no means to supply bias to the filter due to the fact that the bias capacitor couples to the pulse forming network of the arc supply. In this study, self-bias was introduced using a low-ohm resistor between the anode of the arc source and the filter entrance. Experiments confirm that bias of pulsed filters can been realized simply by using the voltage drop across a self-bias resistor.