Spectroscopic investigation on the near-substrate plasma characteristics of chromium HiPIMS in low density discharge mode, Plasma Sources Sci. Technol. 29（2020）015013

Xiao Zuo, Dong Zhang, Rende Chen, Peiling Ke, Magus Odén, Aiying Wang*

【Abstract】Highpowerimpulsemagnetronsputtering (HiPIMS)dischargepromiseshighionizationfractionand energetic ions in comparison with dc magnetron sputtering discharge. But acknowledge on the characteristics of HiPIMS plasma in the near-substrate region (substrate vicinity), which is of great importance for film deposition, is still limited. Here, optical emission spectroscopy (OES) combined with the collisional-radiative modelling are developed and used to determine the electron temperature and the number density of neutral sputtered atom for the chromium HiPIMS plasma in substrate vicinity. The OES analysis demonstrated the HiPIMS discharge of Cr sputtering process in low density mode was dominated by the electron impact ionization of argon atoms and excitation of chromium atoms. As the HiPIMS plasma in the substrate vicinity is far from the local thermal equilibrium state, the relative intensities of transition lines to ArI 4p states was used to calculate the electron temperature. Subsequently, the neutral chromium atoms density about 1017 m−3 was reported in the near-substrateregion.Our findingshave importantimplications for species generation in low density HiPIMS discharge, with applications in synthesis of dense chromium coatings.

Keywords: high power impulse magnetron sputtering, optical emission spectroscopy, electron excitation temperature, chromium atoms density, near-substrate region