Two-dimensional particle-in-cell plasma immersion ion implantation simulation of gear/windmill geometry in cylindrical co-ordinates along the (r–θ) plane

Plasma immersion ion implantation (PIII) into gear/windmill structures is simulated by the particle-in-cell (PIC) method in cylindrical co-ordinates. In cylindrical co-ordinates, the gear/windmill geometry becomes a periodic regular structure. An equal number of particles are placed inside the cell with the same angular and radial distance. The ion density represented by each particle is obtained and varies according to the radial distance of the particle. PIII simulation of a rectangular trench is carried out and compared with the cylindrical gear/windmill. The evolution and distribution of the potential and ion density contour lines are the same for these two geometries. The incident doses of a gear (windmill) will be larger than that of the trench. It is due to the space compression in cylindrical co-ordinates along the decreasing radial direction. The incident doses will thus be underestimated when treating a gear tooth using a rectangular trench.