Numerical Simulation of Metal Plasma Immersion Ion Implantation (MePIIID) on a Sharp Cone and a Fine Tip by a Multiple-Grid Particle-in-Cell (PIC) Method

A multiple-grid particle-in-cell (PIC) method in r-z cylindrical coordinates is developed to study metal plasma immersion ion implantation and deposition (MePIIID) of a sharp cone with a fine tip. At the boundary between the coarse and fine grids, the cells are subdivided into smaller regions so that the effective volume of each node does not overlap with each other when calculating the ion density from PIC weighting. In a previous paper, the ion dose, which is defined as the accumulated implanted ions per area, showed a sharp decrease near the cone tip [Cornet J. Appl. Phys., vol. 96, p. 6045, 2004]. However, the tip of the cone was described by only one single point. By applying a multiple-grid method to numerically simulate the MePIIID on a sharp cone with a fine tip, it is revealed that the highest dose is located at the center of the tip, and it is concluded that the sharp decrease in dose in a previous paper is an artifact of the single point. A multiple-grid system with three different cell sizes, i.e., 2, 1, and 0.5 mm, is used in the simulation. The tip of the cone is represented by a sphere in tangential contact with the edge of the cone