On the anisotropy and thermalization of the metal sputtered atoms in a low-pressure magnetron discharge

Space-resolved velocity distributions of titanium atoms sputtered in a direct-current (dc) magnetron discharge working at low pressure (0.4 Pa) were investigated using the laser-diode–induced fluorescence technique. A blue-light laser diode, covering the Ti 3 d 2 4 s 2 -3 d 2 ( 3 F )4 s 4 p ( 1 P 0 ) transition λ 0 =398.289 nm, was used to excite neutral Ti atoms and to measure their Doppler absorption profile through the induced fluorescence signal. Taking advantage of the very narrow laser linewidth, energetic and thermalized atoms can be clearly distinguished. Moreover, flux distributions of sputtered atoms along the laser direction were deduced and discussed.