High dose metal ion implantation

To affect non-electronic surface properties (wear, corrosion and so on) the implanted material must reach measureable atom percentages, on the order of 10%, requiring ion implantation does in the range of 1017/cm2. For this reason, the MEVVA metallic ion source, developed at Lawrence Berkeley Laboratory, has been modified to provide metal ions for high dose metal ion implantation. The modifications inlcude increasing the arc efficiency, increasing beam spot size, and increasing beam divergence. The extracted beams have been characterized as to beam cross section and the depth profiles of implants. Time-average beam currents in excess of 20 mA have been extracted. Beams of titanium, tantalum, and other refractory metal ions, plus other refractory materials, such as titanium carbide, have been extracted and used to produce modifications in the surface properties of materials. (orig.)