Pressure Effect on the Velocity and Flux Distributions of Sputtered Metal Species in Magnetron Discharge Measured by Space-Resolved Tunable Diode Laser Induced Fluorescence

The pressure acts on the sputtered species resulting in their thermalization. Space-resolved velocity distributions of titanium atoms sputtered in a direct-current magnetron discharge were investigated using the tunable diode-laser induced fluorescence technique (TD-LIF). The titanium 3d24s2 − 3d2(3F)4s4p(1P0) transition centred at λ0 = 398.289 nm was used to excite neutral Ti atoms and to measure their velocity distribution profile through the TD-LIF signal measured at λTD-LIF = 736.31 nm. Two groups of metallic particles, namely energetic and thermalized atoms, could be clearly distinguished and the corresponding flux distributions along the laser beam direction were deduced. The paper discusses the relative importance of the energetic atoms versus the discharge pressure especially in the vicinity of the target.