金属离子高温注入金属靶传质机制研究

【作者】 常海威；

【导师】 雷明凯；

【作者基本信息】 大连理工大学 ， 材料学， 2004， 硕士

【摘要】 本文针对金属离子高温注入金属靶的传质机制进行了理论计算和实验研究。首先，结合粒子与固体相互作用理论与辐照增强扩散理论建立了金属离子高温注入金属靶的传质模型。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—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。其次，进行了注入能量120 keV，注入剂量5×10¹⁶cm^-2，1×10¹⁷ cm^-2的Al离子注入温度分别为RT，250℃，500℃的Fe靶的实验研究。采用X射线衍射（XRD）和Rutherford背散射（RBS）分析注入表面的相结构和注入试样的注入粒子浓度—深度分布。实验表明，靶温度的升高导致注入过程中新相的形成，进而影响注入粒子的传质行为，而注入剂量的增加导致局部温度升高，并且提供更多的过剩空位促进注入粒子的扩散。最后，利用建立的金属离子高温注入金属靶传质模型计算了本文Al注入Fe实验条件下的注入离子的浓度—深度分布以及计算了Cr-Al，Ni-Al，Fe-Al体系在不同温度、不同能量、不同注入剂量下的浓度—深度分布，计算结果与实验测量结果相符。更多还原

【Abstract】 The mass transfer mechanism of metal ions implantation into metal target at elevated temperature was studied systematically by doing the experiments and building up the theoretical model. Firstly, A mass transfer model has been built up for metal ion implantation into metal target at elevated temperature, based on the transport in matter of ions and the radiation enhanced diffusion theory. With the model, the ion implantation process at elevated temperature was simulated by the Monte Carlo method and the local saturation behavior in the crystal target simulated using a maximum allowed atomic fraction. Moreover, the diffusion process was described with the radiation enhanced diffusion theory. Thus the concentration-depth profiles of the implanted species were determined from the diffusion equations for the implanted species and nonequilibrium vacancies, and the radiation enhanced diffusion coefficient was obtained by taking into account the linear annealing defects. The nonequilibrium vacancy source function and the surface sputtering effects were introduced in the diffusion equations. Secondly, Al ions were implanted into Fe target at the temperatures of RT, 250 ?, 500 ?3, at the implanted energy of 120 keV, with the implanted doses of 5X 1016 ions cm2, 1 1017 ions cm2. The phase structure of samples was analyzed by X-ray diffraction analysis (XRD) and the concentration-depth profiles of implanted species were obtained from Rutherford backscattering spectrometry (RBS). According to the results of XRD and RBS the effect of target temperature and implantation dose on mass transfer process was analyzed, which showed that the elevated target temperature affect the mass transfer process by the new intermetallic phase formed during ion implantation at elevated temperature and the increase of implantation dose resulted in the temperature elevated in some part of the target and provided more available vacancies which could improve the diffusion process. Thirdly, the concentration-depth profiles of Al ions implantation into Fe target were calculated at given experimental conditions done in this paper, and the concentration-depth profiles of Cr, Ni, Fe ions implantation into Al target were calculated at different target temperatures, at different implantation energies and with different implantation doses. The calculated results were consistent with the experimental ones.更多还原