Study of Cl2/Ar transient plasmas using a dynamic global model

Cl2/Ar plasmas are widely used in plasma processes. Recently, innovative plasma recipes have been developed that utilize transient plasmas to reduce gas consumption and optimize processes. The present study examines the kinetics play in transient plasmas, with a particular focus on the kinetics of residual species following a feed gas switch (Cl2→Ar) for various working parameters. It was observed that high pressure (>3 Pa) and low gas flow rate (<50 SCCM) contribute to long residual species lifetime (>100 ms), while the RF source power does not significantly affect residual species lifetime. The investigation focused on the minimum feed gas switch duration to align the plasma composition with the machine parameters. The results demonstrate that at high pressure, fast feed gas commutation cannot bypass the plasma kinetics, and longer feed gas switch duration may be required. Finally, abrupt RF source power variations induce drastic deviations of electron temperature and density at a small time scale (<10−4s). Such a result originates from the change of electron collision rate.