Carbon arc plasma transport through different off-plane double bend filters

An off-plane double bend (OPDB) magnetic filter is used to remove macroparticles from the plasma beam of cathodic vacuum arcs, making it suitable for the preparation of high quality thin films. A filter with high plasma transmission efficiency is desirable and essential for high deposition rate, which is the key to the commercialization of the technology. Hence, an investigation has been carried out to study the carbon arc plasma transport under varying arc current and magnetic field conditions. The plasma efficiency tests were carried out on different sizes of off-plane double bend (OPDB) filters by measuring the ion saturation output current and ion density using a copper plate and Langmuir probes, respectively. It was found that in our FCVA systems, there exists an optimum arc current operation for obtaining the maximum plasma efficiency. This seems to be as an important factor for future filter design.