Plasma and floating potentials in magnetron discharges

This letter reports on great differences in values of the plasma U_p and floating U_fl potentials in sputtering discharges generated by single and dual magnetrons. It is shown that (i) the differences in U_p and U_fl result in strongly different properties of films sputtered by single and dual magnetrons at the same power delivered to the magnetron discharge, (ii) in the direct current single and dual magnetron discharges, the values of U_p and U_fl strongly depend on the electric conductivity of the surface of the grounded deposition chamber, and (iii) a pulsed dual magnetron with a closed magnetic B field is the only one sputtering system, which enables us to sputter the films with fully reproducible properties.