Origin of the energetic ions at the substrate generated during high power pulsed magnetron sputtering of titanium

摘要: HiPIMS plasmas generate energetic metal ions at the substrate as a major difference to conventional direct current magnetron sputtering. The origin of these is still an open issue, which unraveled by using two fast diagnostics: time resolved mass spectrometry with temporal resolution 2 $\mu$s and phase optical emission spectroscopy 1 $\mu$s. A power scan from dcMS-like was performed, 2-inch titanium target sputter source argon working gas. Clear differences in transport well properties Ar$^{+}$, Ar$^{2+}$, Ti$^+$ Ti$^{2+}$ were observed. For discharges highest peak densities high group could be identified. cold always present. It found that hot are observed only, when plasma enters spokes regime, can monitored oscillations IV-characteristics MHz range picked up used VI-probes. These correlated phenomenon explained amplification Hall inside ionization zones. To explain presence ions, we propose double layer (DL) confining spoke: if atom becomes ionized region it accelerated because DL higher energies whereas its energy remains unchanged outside. In applying this model our measurements phenomena several other groups explained. Only present confined particles gain enough leave magnetic trap. We conclude findings spoke represents essence plasmas, explaining their good performance for material synthesis applications.