毫秒激光对CCD的热与热应力损伤的研究
关键词 毫秒激光 温度场 应力场 CCD 有限元
毕业设计说明书（论文）外文摘要
Title Analysis of the thermal and mechanical damage in CCD induced by millisecond laser
Abstract
The interaction of 1064nm millisecond laser and charge coupled device (CCD) is investigated. A 3D mathematical model is established via COMSOL Multiphysics Calculation software. By using the finite element method(FEM),the transient temperature and stress fields are calculated .The temporal and spatial distributions of temperature and stress in the key regions during millisecond laser interaction with CCD are obtained. It indicates that the temperature rises with the enlargement of laser energy .The damage sequence of different units of the CCD induced by melting and stress is analyzed. Firstly ,the microlense softens after reaching its melting point .Secondly ,the shading aluminum film in the laser center melts,and then peels off because of the mutation of the thermal stress on the interface.At the same time , SiO2 fractures due to the large tensile stress, which results in short circuit between the shading aluminum film and polysilicon electrode. As a result , the adjacent electrodes cannot transfer charge and the CCD device becomes invalid locally .Increasing the laser energy makes the shading aluminum film melt through ,meanwhile both the silicon substrate and SiO2 occur melting damage ,causing short circuit between the adjacent electrodes and the damage of the silicon substrate that produces signal charge,as a result ,the CCD becomes invalid completely.
Keywords the millisecond laser the temperature fields the stress fields CCD FEM
目次
1 引言 1
1.1激光与CCD相互作用的研究现状 2
1.2本文研究的主要工作 4
2 数值模拟 6
2.1 MOS型CCD结构 6
2.2 数值计算模型 6
2.3 热控制方程 8
2.4 弹塑性控制方程 10
2.5 材料参数 14
3 计算结果与分析 16
3.1 温度场分析 16
3.2 应力场分析 19
结 论 23
致 谢 24
参考文献 25
1 引言
电荷耦合器件CCD由于体积小，重量轻，灵敏度与分辨率高，功耗与成本低等特点，广泛用于监控、摄像、识别和测量等领域[1]。而在光电对抗中，由于激光光源具有方向性好、亮度高等优点，使得电荷耦合器件CCD极易受到激光的干扰甚至损伤。因此，对激光与CCD相互作用机制进行研究，具有重要应用意义。