高斯长脉冲激光辐照单晶硅温度场的数值模拟

Numerical Simulation of Temperature Field of Single-crystal Silicon Irradiated by Gauss Long Pulse Laser

建立二维轴对称模型,通过Matlab软件对长脉冲高斯激光与单晶硅相互作用的加热过程进行数值模拟。分析不同激光功率密度和辐照时间作用下单晶硅的温度分布和温度历史,估算单晶硅的熔融损伤阈值和热量沉积深度。结果表明:单晶硅的熔融损伤阈值的功率密度I_0=0.22 MW/cm^2且激光热量沉积深度大约在1 mm范围内;单晶硅的温度随激光功率密度和辐照时间的增加而升高,且随着光斑半径方向的延伸与靶材厚度的增加而逐渐减小;在脉冲作用期间,硅表面中心温度迅速上升,这主要由高斯激光的能量分布特点决定;在激光作用结束后,辐照区的热量通过热传导效应从高温区向低温区转移,单晶硅的表面中心温度随时间的增加而缓慢下降,最后趋于室温。

The two - dimensional axial symmetric model was established to numerically analyze the process of heating of the gauss long-pulse laser with the single -crystal silicon（SCS）. With the different laser power density and irradiating time, the gauss long-pulse laser interactions with the SCS in the temperature distribution and evolvement were analyzed. The melting damage threshold and heat deposited depth of single - crystal silicon were estimated. The results show that the melting damage threshold of single - crystal silicon is about 0.22MW/cm^2 and the heat deposited of long laser pulse in the SCS surface is around one millimeter. The temperature of single -crystal silicon will be enlarged as laser power density and irradiating time increasing, while the temperature of SCS will decrease along with stretching of speckle radius direction and increase of targets thickness. The temperature of center surface of SCS will rise rapidly during the action of laser, which is mainly decided by the gauss laser energy distribution, and after the action of laser, the heat of irradiating zone flows from the high temperature area to the low temperature area by the effect of heat conduction, with the result that The temperature of center surface of SCS will decrease slowly as time increasing and eventually tend to room temperature.