硼掺杂纳米硅薄膜的多脉冲激光熔覆数值模拟及实验研究

为研究多脉冲激光的热累积效应对硼掺杂纳米硅薄膜熔覆过程的影响，采用单温模型，利用三维有限元方法对激光与硅薄膜的相互作用过程中温度场的分布进行了数值模拟，得到了多脉冲激光耦合情况下的温度场变化规律。仿真结果表明:与单脉冲相比，在多脉冲激光作用下，峰值温度增加了3.2%，熔池尺寸扩大了18.75%，同时热影响区范围也明显增加；激光辐照后，熔覆层表面温度下降，但基体温度仍会继续上升，多脉冲热累积效应为纳米硅薄膜中硼元素扩散提供了有利条件。最后，通过单脉冲及多脉冲激光熔覆实验，分析了熔覆硅薄膜后的熔覆层表面状况的差异，并获得了激光熔覆辅助硼元素扩散的一般规律，为硼掺杂纳米硅薄膜的激光辅助扩散技术在半导体器件中的应用提供了条件。

Numerical simulation and experimental study of multi-pulse laser cladding of B doped Si nano-film

In order to study the influence of the thermal accumulation effect of the multi-pulse nanosecond laser on the cladding process of the boron(B) doped silicon(Si) nano-film, the single-temperature model and the three-dimensional finite element method were used to numerically analyze the distribution of temperature field during the interaction process between the laser and the Si film, then the law of temperature field change under multi-pulse coupling was obtained. Compared with a single pulse, the simulation results of the multi-pulse laser action shows that the peak temperature has increased 3.2%, the size of the molten pool has enlarged 18.75%, and the range of the heat-affected zone has also significantly increased; after the laser irradiation, the surface temperature of the cladding layer drops, while the substrate temperature will continue to rise. The multi-pulse heat accumulation effect provides favorable conditions for the B diffusion in the Si nano-film. Finally, through single-pulse and multi-pulse laser cladding experiments, the different conditions of the cladding layers were analyzed, and the general law of the B diffusion assisted by laser cladding was obtained. The technology of laser-assisted B doped Si nano-film will provide the foundation for the applications in semiconductor devices.