Simulation of dose uniformity for different pulse durations during inner surface plasma immersion ion implantation

Without the line-of-sight limitation, plasma immersion ion implantation (PI LI) emulates conventional beam-line ion implantation in inner surface modif ication of industrial components. However, dose uniformity on the inner sur face is critical. Inner surface PIII of a cylindrical bore is modeled using a two-dimensional fluid model. It is found that the retained dose is not u niformly distributed on the inner surface and the maximum dose is observed away from the edge. The exact location of the maximum dose, which varies wi th the implant pulse duration, is closer to the center when the pulse width is longer. The maximum relative difference of the retained dose along the interior also depends on the implant pulse duration. It is smaller for a lo nger pulse duration after a threshold value has been exceeded. (C) 1999 Ame rican Vacuum Society. [S0734-211X(99)02202-7].