Current–voltage characteristics and fast imaging of HPPMS plasmas: transition from self-organized to homogeneous plasma regimes

Abstract

Current–voltage characteristics within the temporal pulse were recorded in high-power pulsed magnetron sputtering discharges for different target materials. These curves allowed identifying at a first glance the existence of separated plasma regimes clearly differentiated by the plasma conductivity and by the spatial arrangement of the plasma emission. We could establish that regimes of high plasma conductivity are univocally associated to the self-organization of the plasma in well-defined ionization zones. As the applied power is gradually increased, the high conductivity regime is abruptly replaced by a regime of high current and low plasma conductivity, associated to homogeneous plasma emission.