High-current-density metal-ion implantation

Design features and preliminary performance data for an ion-implantation system that derives its broad, high-current-density beam directly from a steady, metal-plasma discharge in a high temperature graphite chamber are described. Metal vapor is supplied by drawing electron current to an anode-potential crucible to vaporize a pure metal in it. Argon used to start the discharge is turned off once sufficient metal vapor is present to sustain it. Extraction of metal-ion beams that are several centimeters in diameter at current densities ranging to several hundred μA/cm2 of titanium or copper onto targets 50 cm from the ion source is demonstrated. The system is simple, reliable, and easy to maintain