Production of multiply charged Si and Fe ions from solid material in a 2.45 GHz electron cyclotron resonance source

Multiply charged ions of Si and Fe are produced from solid material in a 2.45 GHz electron cyclotron resonance (ECR) ion source. The ECR plasma is confined in the mirror field with the octupole magnetic field. Operating gas is usually Ar. The pure Si or Fe target is inserted into the ECR plasma from the mirror end plate along the geometrical axis; the DC bias voltages are applied for direct sputtering. The charge state distributions (CSD) of the extracted ion current are investigated in various experimental conditions. Multicharged ions up to Si/sup 4+/ and Fe/sup 5+/ have been produced by using pure Si and Fe targets, respectively. The operating parameters are mainly DC bias voltages, target positions, pressures, and microwave powers. The ratio of the total multicharged Si ions current to the total Ar ions current is about 13%. We will discuss the dependence of multicharged ion current on various experimental conditions in these experiments.