The time-resolved ion energy distribution functions (IEDF's) at the substrate position in a HiPIMS discharge were investigated using a commercial quadruple energy-resolved mass spectrometer, incorporating a double gating ion shuttering technique. A titanium target (Ti) was sputtered in argon gas at 0.54 Pa pressure, with an average power of 680W, a frequency of 100Hz and a pulse width of 100 (mu)s. The IEDF's show a peak in the Ar~(+) counts at the energy equivalent to the local plasma potential V_(p) (3V), however for Ti~(+) ions a similar peak was observed at 22 eV. The peaks for Ar~(+) ion counts occurred at times 30 (mu)s and 60 (mu)s after the initiation of the cathode discharge pulse (V_(d)). We speculate that the first peak, occurred at 30 (mu)s was due to electron impact ionization, whereas second peak, occurred at 60 (mu)s, was due to asymmetric charge exchange ionization mechanism.
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