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本文用计算机解差分方程组的方法求解脉冲激光诱导扩散过程中的热导方程和杂质扩散方程,求得在硅片中不同深度层的温度分布、各层温度随时间的变化以及杂质扩散分布.要想得到有效的杂质扩散结果,激光强度必须大于一定值致使有一定深度的硅层发生熔化,从而出现液相扩散过程.影响杂质扩散结果的主要因素是脉冲激光功率密度和激光脉冲宽度,因为这两个因素是决定硅表面层熔化的深度和表面层保持液相的时间,从而决定扩散结果.对于不同波长的激光,硅片的光吸收系数和反射系数不相同也会对杂质扩散结果有所影响.计算机模拟计算的结果与染料脉冲激光对硼在硅片诱导扩散的实验结果相当符合.我们对结果还作了初步讨论.
In this paper, the thermal conductivity equation and the impurity diffusion equation in the pulse laser-induced diffusion process are solved by the method of computer solution of the differential equations. The temperature distributions of different depth layers in the silicon wafer, the change of the temperature with time and the impurity diffusion distribution are obtained. In order to obtain effective impurity diffusion results, the laser intensity must be greater than a certain value so that a certain depth of the silicon layer is melted, resulting in liquid phase diffusion process.The main factors affecting the impurity diffusion results are the pulse laser power density and laser pulse width, because Two factors determine the depth of melting of the silicon surface layer and the time it takes for the surface layer to remain in the liquid phase, which determines the result of the diffusion. For different wavelengths of laser light, the difference between the light absorption coefficient and the reflection coefficient of the silicon wafer will also have an effect on the impurity diffusion .The results of computer simulation are in good agreement with the experimental results of dye-induced pulsed laser on the diffusion induced by boron in silicon wafer.We also discussed the results.