Time-of-flight mass spectrometric diagnostics for ionized and neutral species in high-power pulsed magnetron sputtering of titanium

A photoionization method using a vacuum ultraviolet laser was applied to the time-of-flight mass spectrometry of ions formed in high-power pulsed magnetron sputtering (HPPMS). This method is a new plasma diagnostic technique for measuring simultaneously the amounts of sputtered ionized and neutral species in HPPMS. The temporal profiles for the amounts of ions and neutrals were observed with respect to the trigger of the pulsed discharge in HPPMS. This result is discussed in connection with the atomic processes of light-emitting ionized and neutral species measured in optical emission spectroscopy for HPPMS.