Experiments in ion implantation were first performed almost 40 years ago by nuclear physicists. More recently, ion implanters have become permanent fixtures in integrated circuit processing lines. Manufacture of the more complex integrated circuits may involve as many as 10 different ion implantation steps. Implantation is used primarily at f luences of 1012–1015 ions/cm2 to tailor the electrical properties of a semiconductor substrate, but causing only a small perturbation in the composition of the target (see the article by Seidel and Larson in this issue of the MRS Bulletin). Applications of implantation had been limited by the small beam currents that were available, but recently a new generation of high-current implanters has been developed. This high-current capability allows implanting concentrations up to three orders of magnitude higher than those required for doping—enough to create a compound.
