Theoretical modeling of plasma processing

This paper reports on kinetic particle simulation modeling of the system consisting of plasma, sheath, material, and an external driving circuit which is carried out. The plasma ion implantation relies on the ion acceleration in the sheath region to a necessary energy (10--50 keV). The dynamic evolution of the sheath is highly nonlinear and complex especially when the applied negative voltage at the target material is modulated at a finite frequency to contain the sheath expansion to a manageable size. By using a kinetic simulation method for a bounded plasma system the authors calculate the average and peak currents, the sheath size, and the implanted ion energy distribution; these results are compared with other analytic and fluid calculations. The Plasma Ion Implantation (PII) Experiment at POSTECH is to be compared with the predictions of these theoretical calculations