Optical emission spectroscopy in deep oscillation magnetron sputtering (DOMS) of titanium

Optical emission spectroscopic diagnostics are applied to determine the temporal evolution and distance dependence from the target surface for deep oscillation magnetron sputtering (DOMS) with a titanium target. In the time evolution of emission intensities for atomic lines of optically emitting species formed in DOMS plasma, the envelope of the peak emission intensity for sputtered neutrals in each pulsed discharge was observed to rise gradually with increasing distance. The increase in the distance dependence of the optical emission corresponds to plasma build-up from gas plasma to metallic plasma, which has been reported in the deposition region using a time-of-flight mass spectrometer in Sanekata et al. [J. Appl. Phys. 131, 243301 (2022)]. On the other hand, the ion confinement effect was strongly observed for sputtered ions in the region up to the edge of the magnetic trap around 40 mm downstream from the target surface for the first pulse discharge.