Fabry–Perot interferometry for measurements of the velocity of sputtered atoms in a magnetron discharge

A planar Fabry–Perot interferometer was utilized to measure the velocity distribution function (vdf) of the atoms sputtered in a dc magnetron discharge. The measurements were performed during the sputtering of several metal targets under different discharge conditions such as applied power, working pressure and the distance from the magnetron target. The results demonstrate that there is a considerable shift of the vdf depending on the working pressure and the atomic weight of the sputtered atoms when the line of sight is perpendicular to the target. At the same time the velocity corresponding to the maximum of the vdf does not vary appreciably with the applied power. The typical net velocity of the sputtering atoms was found to be about 2 km s −1 , which is in good agreement with the data obtained recently by other diagnostic methods.