质子辐照诱发CIS暗信号噪声的理论模拟和实验研究

Thanks to the low power consumption, high levels of integration and low cost，Complementary Metal Oxide Semiconductor Image Sensor (CIS) has become a key element of optical imaging system and have been widely used in spacecraft. However, the CISs used in these harsh radiation environments are susceptible to damage by protons. Fewer researches have been carried out to study the proton radiation effects on dark signal noise of CISs in our country, which would restrict the development of the new spacecraft and the performance of its orbit. Based on present study status, the proton radiation effects on the dark signal noise of CISs will be carried out by combining with theoretical simulation and experimental data. The sensitive region of the proton radiation in CIS will be obtained by analyzing the mechanism of the radiation effects. The particle transport simulation works will be carried out and the ionizing energy loss (IEL), primary knock-on atoms (PKA), three dimensional distributions of initial bulk defects will be calculated. The Technology Computer Aided Design (TCAD) simulation work will also be carried out and the dark signal noise model will be established. The irradiation experiments of CISs with different pixel size and structure will be carried out. The experimental results will be discussed in comparison with calculation results to show the effectiveness of this model. The achievements of this paper will provide basis of theories and experimental techniques for CISs radiation damage evaluation and radiation hardening study.

互补金属氧化物半导体图像传感器(CIS)因其功耗低、集成度高、成本低等优点被逐步应用于航天器成像系统中，其空间质子辐照损伤诱发暗信号噪声问题倍受关注，严重制约了我国新型航天器的顺利研制与在轨效能发挥。本项目在充分调研CIS辐照损伤研究的基础上，采用理论模拟和实验研究相结合的方法，开展质子辐照损伤诱发CIS暗信号噪声研究。通过分析辐照后暗信号噪声增大的物理机制，明确CIS质子辐照损伤的敏感区域；通过开展辐照损伤粒子输运模拟，研究质子在CIS中的电离能量损失、初级反冲原子、初始缺陷三维分布等；将能量损失、缺陷分布等作为初始条件，开展基于TCAD的CIS辐照损伤仿真模拟，建立质子辐照后CIS暗信号噪声模型；以不同像素尺寸、结构的CIS为研究对象，开展辐照实验，并将实验结果同理论模拟结果进行对比，检验暗信号噪声模型的有效性。本项目的研究工作将为CIS抗质子辐照损伤评估和加固技术研究提供理论基础。

互补金属氧化物半导体图像传感器(CIS)因其功耗低、集成度高、成本低等优点被逐步应用于航天器成像系统中，其空间质子辐照损伤诱发暗信号噪声问题倍受关注，严重制约了我国新型航天器的顺利研制与在轨效能发挥。三年来，经过课题组全体成员的共同努力工作，在质子辐照诱发CIS暗信号噪声的理论模拟与实验研究方面开展了系统的研究工作，取得了若干进展。主要工作如下：1）根据质子与物质的相互作用机制，模拟计算了质子在材料中的输运过程和对器件的辐照损伤，开展了基于TCAD的CIS质子辐照损伤仿真模拟；2）以不同结构的国产大面阵CIS为研究对象，开展了不同能量质子辐照实验，中子辐照实验和Co-60 γ射线辐照实验，获得了暗信号噪声的退化规律和典型特征；3）揭示了CIS质子辐照损伤诱发暗信号增大的物理机制，研究结果表明：位移损伤在空间电荷区产生的体缺陷会导致暗信号显著退化；电离损伤在浅沟道隔离区与PPD接触界面、PPD与传输栅交叠处及读出电路中产生的氧化物陷阱电荷和界面态会导致暗信号显著退化；4）建立了质子辐照后CIS的暗信号噪声模型，研究结果表明：低能质子辐照过程中既会产生总剂量效应，又会产生位移效应，二者均会导致暗信号噪声增大；总剂量效应诱发的暗信号噪声一般呈高斯分布，而位移损伤诱发的暗信号噪声一般呈伽马分布，质子辐照后暗信号噪声分布为高斯分布和伽马分布的卷积，并结合实验结果，验证了该结果的正确性。本项目的研究工作为CIS抗质子辐照损伤评估和加固技术研究提供理论基础。本项目圆满完成了计划任务书规定的各项研究任务。