Experimental results of a dc glow discharge source withcontrolled plasma floating potential for plasma immersion ionimplantation

Abstract

A simple dc glow discharge with controlled plasmafloating potential was applied as a novel source for plasmaimmersion ion implantation with excellent results. The glow discharge source is normally used for the conditioning of fusiondevice chambers, taking advantage of the available highaccelerating potential which is necessary for the ion bombardment of the walls. Combining an electron-emitting hotfilament with this source, it was possible to get a stabledischarge at pressures as low as 8×10-4 mbar and, operating it with potentials lower then 70 V, it was possible toreduce the Si sample etching down to zero from 2500 Å seen atpotentials of native 350 V, when exposure times of 750 min were used in the sample's surface subjected to plasma ionimplantation of nitrogen. As a result, retained ion doses of1.5×1017 cm-2 were obtained in etching-free Sisurfaces.