激光热效应对CMOS探测器的干扰机理分析

Jamming mechanism analysis of laser thermal effect on CMOS detector

为了研究激光热效应对CMOS探测器的干扰效应,建立了激光辐照CMOS探测器固体传热的有限元仿真模型,仿真了激光辐照CMOS的光热效应,得到CMOS探测器的表面温度分布及Si层表面的温度曲线。根据半导体电子空穴对产生公式,得到波长为1064nm的不同功率密度的激光辐照CMOS而产生的光生载流子、热生载流子。根据CMOS对于1064nm激光的饱和功率密度阈值5.87×10^（-3）W/cm2,得到CMOS的载流子饱和阈值。对比不同功率密度的激光辐照CMOS时的三种载流子。结果表明,功率密度为350W/cm2的激光辐照CMOS时,热生载流子大于了CMOS的载流子饱和阈值,证明热生载流子已经占满了像元,激光的热效应已经干扰了CMOS探测器。

In order to study the interference effect of photo-thermal effect on CMOS detector,the heat transfer in solids simulation model of laser radiation CMOS detector is established based on finite element method. The surface temperature distribution of CMOS detector and the surface temperature profile of the Si layer are obtained by simulating photo-thermal effect of laser irradiation. According to the formula of semiconductor electron hole pairs,the photo-generated and thermogenic carriers are produced by irradiating 1064 nm CMOS with different power densities. The carrier saturation threshold of CMOS is obtained according to saturation power density threshold of 5. 87 × 10-3 W/cm^2 for 1064 nm lasers. In this paper,we compare the three kinds of carriers when irradiating CMOS with different power densities. The results show that when the power density is 350 W/cm^2,the thermal carrier is larger than carrier saturation threshold of CMOS. It is proved that the thermal carrier has filled the pixel and the thermal effect of the laser has disturbed CMOS detectors.