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 thermal and stress fields in the multilayered structure of silicon-based positive-intrinsic-negative(PIN) photodiode irradiated by millisecond(ms)-pulsed laser, we use the thermal elasto-plastic constitutive theory and the equivalent specific heat method, to deal with the phase change latent heat. The multiple-heat-source, especially the influence of reflection from bottom-aluminum-electrode, and the effect of the nonlinearity of material parameters are taken into consideration. A 2-D simulation model is built by means of the finite element simulation software of COMSOL Multiphysics. The surface and the internal each layer showing changes of the transient distribution and evolution of the thermal and stress fields with space and time can be obtained. Because of taking account of the reflection of the aluminum electrode, the temperature of the aluminum electrode rises slightly. On this basis, we analyze the hard failure mechanism of ms-pulsed laser irradiated silicon-based PIN, and the mechanical damage before melting that leads to a malfunction of silicon-based PIN detector.
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