中文摘要：

模具表面改性日益受到人们重视。本文采用二维Particle—in-cell／Monte Carlo Collision模型对等离子体浸没离子注入处理凹模型腔内表面的鞘层动力学及均匀性进行了研究。考察了电压脉宽对鞘层中电势分布、离子的运动状态以及型腔内表面离子注入剂量、能量和角度的空间分布的影响。结果表明随着电压脉宽的增加，凹模型腔内表面的注入剂量不均匀性增加，同时注入到内表面的高能离子数目也增加。脉冲宽度变化对注入角度影响不大，离子以接近垂直的入射角度注入到型腔底部，而在侧壁上离子注入角度接近45°。当脉冲宽度较大时，发现少部分注入到侧壁上的离子以一定角度从下往上注入到样品表面，这是由于碰撞效应造成的。从能量和剂量的角度，存在一个合适的脉冲宽度，过大的脉宽会引起剂量不均匀性增加，同时离子注入能量也会下降。

英文摘要：

The impact of the plasma pulse width on various parameters of interest, including the potential distribution in the plasma sheath, ion motions and dosage, sputtering energy and incident angle, in the surface modification by plasma ion implantation of cavity mold of metal dies was numerically simulated with the two-dimensional particle-incell / Monte Carlo collision model. The simulated results show that the pulse width significantly affects the quality of ion implantation. As the width increases, the implantation dosage becomes decreasingly less uniform with increasing number of high energy ions. However, the width little affects the incident angle of the impinging ions. The pulse width can be optimized by compromising the ion energy and dosage, because large pulse width spoils uniformity of the ion beam, and decreases energies of the impinging ions.