Investigation of the thermalization of sputtered atoms in a magnetron discharge using laser-induced fluorescence

The thermalization of sputtered atoms in a magnetron discharge was investigated using laser-induced fluorescence. The results clearly indicated for the first time that the velocity distribution agrees well with the Thompson formula [M. W. Thompson, Philos. Mag. 18, 377 (1968)] for d/λ≪1, while a thermalized component becomes appreciable for d/λ≳1, where d is the distance from the cathode surface and λ is the mean free path of sputtered atoms for collisions with filling gas atoms.