Ion dose uniformity for planar sample plasma immersion ion implantation

In spite of recent progress on plasma immersion ion implantation (PIII) in semiconductor processing, for example, formation of silicon on insulator and shallow junctions, ion dose, and energy uniformity remains a major concern. We have recently discovered that the sample stage (chuck) design can impact ion uniformity significantly. Using a theoretical model, we have investigated three different chuck designs and conclude that insulators on the stage can alter the adjacent electric field and ion trajectories. Even though the conventional stage design incorporating a quartz shroud reduces the load on the power supply and contamination, it yields ion dose and energy nonuniformity unacceptable to the semiconductor industry. Thus, for semiconductor applications, the stage should be made of a conductor, preferably silicon or silicon coated materials and free of quartz.