Limited sheath-collision for plasma immersion ion Implantation and its influence on impact energy and dose uniformity

To increase the efficiency of plasma immersion ion implantation (PIII) batching, a limited sheath-collision method is proposed. Sheath-collisions between three cylinders with a triangular configuration are studied using a 3-D particle-in-cell simulation. Influences of sheath-collision extent on dose uniformity are obtained, and a criteria for determining the critical that requires that sheath-collision at the center of the triangle be avoided is proposed. In addition, depth profiles of the implanted ion obtained in PIII batching demonstrate that the critical sheath-collision value has an obvious influence on the implantation depth and dose uniformity.