Dose and energy uniformity over inner surface in plasma immersion ion implantation

The absence of the line-of-sight restriction makes plasma immersion ion implantation an excellent interior surface treatment technique. In our experiments, we implanted both the outside and inside surfaces of a set of hollow cylindrical samples with and without a grounded conductive electrode positioned along the center of the bores to evaluate the impact energy as well as dose uniformity along the specimens. Our experimental results show that the use of the coaxial electrode increases the impact energy by 43% and retained dose by 71%. The nonuniformity is 20% to 30% and is worse with larger bore length.