飞秒激光作用下硅材料的热力响应  

Thermomechanical Response of Silicon Materials Heated by Femtosecond Lasers

作　　者：郭春凤[1] 齐文宗[1] 王德飞[1] 于继平[1] 

机构地区：[1]四川大学电子信息学院,四川成都610064

出　　处：《激光与红外》2009年第3期260-263,共4页Laser & Infrared

摘　　要：为描述飞秒激光辐照半导体材料的热力响应过程,扩展了热电子崩力和自恰场两种模型,得到了完全耦合的非线性热弹方程组。在单轴应力条件下,利用有限差分法,计算了500 fs脉冲激光作用下硅膜内载流子温度、晶格温度、热应力和热电子崩力的变化情况,同时考虑了能量密度和薄膜厚度两个因素的影响。数值结果表明:能量密度越高达到热平衡所需的时间就越长;对于比较薄的硅膜,随着激光作用时间的增加,热应力的双峰逐渐增加并由前后表面同时向薄膜的中间移动。To describe thermomechanical response of semiconductors subjected to femtosecond laser heating,the hot-electron blast and complete self-consistent models are extended. A set of fully coupled thermoelasticity equations is derived based on the assumption of uniaxial stress. Numerical analysis is performed for a thin silicon film heated by a 500fs laser pulse using a finite difference method. It is shown that it takes a longer time for a high fluence to establish the thermal equilibrium than that for a low fluence. On the other hand, as time prolongs, two peaks of thermal stress inrease gradually and move towards the center region of the film for a very thin silicon film.

关 键 词：飞秒激光 超快热弹模型 硅膜 热应力 

分 类 号：O437[机械工程—光学工程] O472[理学—光学]