Spatially resolved model of the discharge current characteristics of axisymmetric radio frequency-driven magnetrons

Low pressure radio frequency (RF) magnetrons find extensive application in various technological fields, for example as a tool for coating substrate surfaces with thin layers of material. This process enhances the substrate’s functional properties, such as scratch resistance or hardness. To enable operation at low pressure, magnetrons utilize a static magnetic field to capture electrons near the target, thereby enhancing ionization and sputtering rates. Meanwhile, the magnetic field drastically impacts the characteristics of the discharge current primarily carried by electrons. It suppresses plasma series resonance (PSR) in the racetrack region while permitting PSR oscillations in off-racetrack regions. This work presents a spatially resolved bulk model of an axisymmetric RF magnetron discharge, encompassing the nonlinearity of the cathode sheath as well as the peculiar effects of the axisymmetric magnetic field on the distribution of electron current density.