High energy implantation with high-charge-state ions in a vacuum arc ion implanter

Abstract

Ion implantation energy can in principle be increased by increasing the charge states of the ions produced by the ion source rather than by increasing the implanter operating voltage, providing an important savings in cost and size of the implanter. In some recent work we have shown that the charge states of metal ions produced in a vacuum arc ion source can be elevated by a strong magnetic field. In general, the effect of both high arc current and high magnetic field is to push the distribution to higher charge states — the mean ion charge state is increased and new high charge states are formed. The effect is significant for implantation application — the mean ion energy can be about doubled without change in extraction voltage. Here we describe the ion source modifications, the results of time-of-flight (TOF) measurements of ion charge state distributions, and discuss the use and implications of this technique as a means for doing metal ion implantation in the multi-hundreds of keV ion energy range.