High‐current metal‐ion source for ion implantation

High‐current metal‐ion beams, as needed for material modification of metal surfaces, can be produced using the MEVVA ion source. In this article a brief description of the ion source is given, and its operational characteristics and preliminary results are presented. A range of metal ions such as Cu, Ti, Al, Fe, Mo, and W, etc., have been extracted from the source. The ion‐beam current is 0.5–1 A (total current in all charge states) and is a function of the cathode material, arc current, and extractor voltage. The beam pulse width is 300–550 μs, the repetition rate several pulses per second, the extraction voltage about 30 kV, and the arc current 150–350 A. The extraction system has a set of three multiaperture extractor grids, including three different sizes: 37 holes 2 mm in diameter, and 207 and 495 holes 1 mm in diameter. The operating pressure is in the 2×10−6‐Torr range, obtained with a diffusion pump.