Two-Dimensional Fluid Model of Pulse Sheath in Plasma Immersion Ion Implantation With Dielectric Substrates

A 2D fluid model is developed to describe the charging effects during plasma immersion ion implantation with dielectric substrates. The spatiotemporal evolution of the surface potential, the accumulated charge dose, and the ion impact angle at the surface of dielectric substrates are calculated with the model. The numerical results demonstrate that the charging effects lead to reduction of the surface potential with time, and the surface potential is nonuniform along the dielectric surface. The lowest value of surface potential is near but not at the edge of the dielectric target. Therefore, the charge accumulation on the dielectric surface is also a function of surface position. The dose nonuniformity is more severe near the edge of the dielectric target. To lengthen the width of the metal electrode that is located below the dielectric target, one can improve the nonuniformity of the accumulated charge dose on the dielectric surface.