Unbalanced dc magnetrons as sources of high ion fluxes

Abstract

We report the characteristics of a new design of magnetron sputter source (a UM-gun), based on the principle of an unbalanced magnetic design, and capable of giving ion fluxes at the substrate greater than the flux of depositing atoms. The dependencies of ion flux and self-bias potential at a typical substrate position for certain target materials (copper and silicon), gas pressures (0.25–5 Pa), gas compositions (Ar with O2, N2, and He), and sputtering power levels (up to 2 kW) have been measured for a particular UM-gun. The results show that such guns can be characterized approximately by an ion flux proportional to the discharge current and a constant self-bias potential.