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为了研究毫秒脉冲激光辐照硅基PIN多层结构产生的温度场和应力场的特点,本文基于热传导理论和弹塑性力学理论,利用等效比热容法处理相变潜热,考虑多个热源,尤其是底层铝电极反射的影响,并考虑硅基PIN探测器每层材料参数的非线性影响,采用有限元模拟软件COMSOL Multiphysics,对毫秒脉冲激光辐照硅基PIN多层结构的过程进行了二维数值模拟,得到了材料表层及内部各层的瞬态温度场与应力场的时空分布和变化规律.结果表明,底层铝电极对激光的反射,使得在底层铝电极处及附近硅层的温度都略有升高.在此基础上,分析了毫秒脉冲激光辐照硅基PIN的硬破坏机理,即熔融前力学损伤导致硅基PIN探测器的功能失常.
In order to study the characteristics of the temperature field and the stress field induced by the pulsed laser-irradiated silicon-based PIN multilayered structure, the heat transfer theory and the elasto-plastic mechanics theory are used to treat the latent heat of phase transformation by the equivalent specific heat capacity method. Considering several heat sources, The influence of the reflection of the aluminum electrode on the bottom and the non-linearity of the parameters of each layer of silicon-based PIN detector were considered. The finite element simulation software COMSOL Multiphysics was used to simulate the microstructure of the PIN- The temporal and spatial distributions and variations of the transient temperature and stress fields in the surface and the inner layers of the material were obtained.The results show that the reflection of the laser by the aluminum electrode at the bottom makes the temperature of the silicon layer at and near the bottom aluminum electrode slightly On the basis of this, the hard failure mechanism of silicon-based PIN irradiated by millisecond pulsed laser was analyzed, that is, the mechanical damage of the silicon-based PIN detector caused by pre-melting mechanical damage.