脉冲激光晶化非晶硅薄膜的有限差分模拟

根据热传导原理，建立了脉冲激光晶化非晶硅薄膜的理论模型。运用有限差分方法研究了不同激光波长、能量密度等因素对薄膜温度变化及相变过程的影响。计算了不同波长激光器对厚度500nm非晶硅晶化的阈值能量密度。结果发现，准分子晶化的阈值能量密度最低，但是在同样的能量密度下，熔融深度却不及使用更长波长的激光器。计算并分析了升高衬底温度对结晶速度和晶粒尺寸的影响，模拟结果较好地验证了实验结论和规律。

Based on the heat conductivity principles, a mathematic model about pulsed laser induced crystallization of a-Si thin film had been developed. With the finite difference method, the effect of varied parameters, such as wavelength and energy density of laser, on the temperature distribution and phase change of the thin film during crystallization was analyzed. The melt threshold energy densities for 500 nm a-Si irradiated with different lasers were calculated. The results show that the crystallization with excimer lasers requires the lowest threshold energy densities. However, it does not create the deepest melt depth, compared with green or red lasers. The effect of different substrate temperatures on the crystallization speed and grain size was analyzed, and the calculated results accord with the experimental results and laws.