中文摘要：

模具表面改性对提高模具使用寿命和生产率有着十分重要的意义。本文采用二维Particle—in—cell／Monte Carlo collision模型对不同气压下等离子体离子注入处理凹模型腔内表面的鞘层动力学进行研究。考察了气压变化对电势分布、离子运动状态及凹模型腔内表面离子注入剂量、能量和角度分布的影响。计算结果表明随着气压的上升，凹模周围的鞘层厚度变薄；随气压上升，凹模型腔底部和顶部端面离子注入剂量和平均注入能量下降，在型腔侧壁上，离子注入剂量和平均注入能量先上升后下降。注入到型腔侧壁和凹模顶部端面上的离子平均注入角度随气压上升而趋向于垂直入射，型腔底部平均注入角度随气压上升略有增大。研究结果表明通过引入一定的碰撞（变化气压）来改善剂量和能量的均匀性是可行的。

英文摘要：

The influence of pressure on surface modification conditions,such as the potential distribution in the plasma sheath,ion motions and dosage,sputtering energy and incident angle in the plasma ion implantation of cavity molds of metal dies,was numerically simulated with the two-dimensional particle-in-cell/Monte Carlo collision model.The simulated results show that the pressure plays a key role in the ion implantation.As the pressure rises up,the sheath thickness above the inner surfaces of the cavity mold decreases,and the beam density and average energy of the impinging ions at the top and bottom decrease,whereas on the sides they first increase,then,decrease.We suggest that the controlled variations in pressure may improve the uniformity of both the implantation dosage and energy,possibly because of particle collisions.