【摘要】 利用注入离子在固体中传输理论和辐照增强扩散理论建立了金属离子高温注入金属Al靶的传质模型,计算了金属离子高温注入的浓度-深度分布.在所建立的传质模型中采用动态Monte Carlo方法模拟离子注入过程,引入饱和浓度限模拟晶体靶局部饱和现象;采用基于辐照增强扩散的扩散方程描述注入粒子扩散过程;根据缺陷线性退火理论确定辐照增强扩散系数;结合杂质原子和非平衡空位扩散方程给出了注入粒子的浓度分布;在扩散方程中引入了空位源函数并考虑了离子溅射造成的表面退让效应.针对离子能量140keV,注入剂量2×10¹⁷cm^-2,温度250,400和510℃的Cr离子注入Al靶计算得到的浓度-深度分布与实验结果相符.更多还原

【Abstract】 A mass transfer model has been built up for metal ion implantation into Al target atelevated temperature, based on the transport of ions in matter and the radiation enhanced diffusiontheory, which is applicable to calculate the concentration--depth profiles of the implanted species. Withthe model, the ion implantation process at elevated temperature was simulated by the Monte Carlomethod and the local saturation behavior in the crystal target simulated using a maximum allowedatomic fraction. Moreover, the diffusion process was described with the radiation enhanced diffusiontheory. Thus the concentration--depth profiles of the implanted species were determined from the dif-fusion equations for the implanted species and nonequilibrium vacancies, and the radiation enhanceddiffusion coefficient was obtained by taking into account the linear annealing defects. The nonequi-librium vacancy source function and the surface sputtering effects were introduced in the diffusionequations. The calculated concentration--depth profiles of Cr ions implanted into Al are consistent withthe experimental ones at the target temperatures of 250, 400 and 510℃, with an ion energy of 140keV and an implanted dose of 2×10¹⁷ ions cm^-2.更多还原