半圆形容器等离子体源离子注入过程中离子动力学的两维PIC计算机模拟

Two-dimensional particle-in-cell simulation of the ion sheath dynamics in plasma source ion implantation of a hemispherical bowl-shaped target

利用两维particle-in-cell方法研究了半圆形容器表面等离子体源离子注入过程中鞘层的时空演化规律.详尽考察了鞘层内随时间变化的电势分布和离子密度分布规律,离子在鞘层中的运动轨迹和运动状态,得到了半圆容器内、外表面和边缘平面上各点离子注入剂量分布规律,获得了工件表面各点注入离子的入射角分布规律.研究结果揭示了半圆容器边缘附近鞘层中离子聚焦现象,以及离子聚焦现象导致工件表面注入剂量分布和注入角度分布存在很大不均匀的基本物理规律.

Plasma source ion implantation into a hemispherical bowl-shaped target is simulated by the two-dimensional particle-in-cell method. The numerical procedure is based on solving the Poisson＇ s equation on a grid and tracing the movement of the ions through the grid. The potential and the ion density distributions in the sheath are studied in detail and the trajectories and dynamic states of ions are considered. The implantation dose and impact angle of the ions at different parts of the target surface are obtained. The ion focusing effect due to the nonuniformity of the sheath potential near the brim of the vessel is observed. The results presented here show that the ion focusing causes the nonuniformity of dose on the target surface.