Sheath expansion dynamics during plasma implantation of insulating materials

摘要

Summary form only given. Plasma immersion ion implantation of insulating materials is complicated, in spite of practical importance with regard to basic research, process development, as well as industrial applications. The capacitance induced by the insulating sample decreases the bombardment energy of the incident ions. The plasma sheath is subsequently deformed due to a different surface potential when the sample and target holder is integrated and treated as one entity. Consequently, nonuniformity of the incident dose and low implant dose results. In this work, plasma sheath formation and propagation are investigated during plasma implantation of insulating polymeric films. A movable probe is used in the experiments and the collected electron current is monitored to determine the time-dependent and space-dependent plasma-sheath dynamics. Two-dimensional numerical simulation is also employed to study the phenomenon. The geometrical configuration and physical properties of the samples are observed to have a critical influence on the plasma sheath dynarnics Our experimental and theoretical results and the related mechanism are discussed.