Time resolved tunable diode laser absoption spectroscopy of dual High Power Impulse Magnetron Sputtering discharges

摘要

Time-resolved measurements have been performed during dual High Power Impulse Magnetron Sputtering (dual-HiPIMS) with two cathodes in a closed magnetic field configuration. The dual-HiPIMS system, operated at a repetition frequency f = 100 Hz and duty cycle of 1 %, was equipped with two different metallic targets (Ti, Cu). The effect of a delay between subsequent pulses on argon excited atom density and temperature was investigated by means of tunable diode laser absorption spectroscopy. It is shown that the peak densities of pulses vary strongly with the delay. We observed an enhancement of metastable density due to pre-ionization effect but more effective than that is the contribution of metal atoms which have smaller ionization energy compare to that of buffer gas atom. Associate with the enhancement of density, the temporal variation of metastable atom temperature in the Cu pulse also transforms from those of low current pulse into the high current one.