质子辐照下4T CMOS图像传感器满阱容量退化模拟研究  

Simulation of Full Well Capacity Degradation of 4T CMOS Image Sensor Irradiated by Proton

作　　者：杨勰 王祖军 尚爱国 霍勇刚 薛院院 贾同轩 焦仟丽 YANG Xie;WANG Zu-jun;SHANG Ai-guo;HUO Yong-gang;XUE Yuan-yuan;JIA Tong-xuan;JIAO Qian-li(Xi’an Research Institute of High-Technology,Xi’an 710025,China;State Key Laboratory of Intense Pulsed Irradiation Simulation and Effect,Xi’an 710024,China;School of Materials Science and Engineering,Xiangtan University,Xiangtan 411105,China)

机构地区：[1]西安高科技研究所,西安710025 [2]强脉冲辐射环境模拟与效应国家重点实验室,西安710024 [3]湘潭大学材料科学与工程学院,湘潭411105

出　　处：《现代应用物理》2021年第3期131-139,共9页Modern Applied Physics

基　　金：国家自然科学基金资助项目(11875223,11805155);国家科技重大专项资助项目(2014ZX01022-301);强脉冲辐射环境模拟与效应国家重点实验室基金资助项目(SKLIPR1803,SKLIPR1903Z,SKLIPR2012)。

摘　　要：以4T CMOS有源像素图像传感器为研究对象,开展了10 MeV不同注量质子辐照导致图像传感器满阱容量性能退化模拟研究,建立了CMOS图像传感器结构模型和质子辐照模型;结合满阱容量计算模型,分析了不同注量质子辐照对光电二极管(PPD)电容、TG沟道势垒及浮置节点(FD)与衬底形成的耗尽层的影响,揭示了辐照诱导满阱容量退化机理;在CMOS图像传感器结构设计基础上,提出了抗辐射设计方案。研究结果表明,质子辐照在氧化层中引入大量的氧化物陷阱电荷和界面态,使得PPD耗尽层展宽,导致光电二极管(PPD)电容下降;质子辐照在氧化层中产生正氧化物陷阱电荷,使得TG传输门沟道Si-SiO_(2)界面处产生感应负电荷,造成TG沟道势垒下降,暗电流增加,间接导致满阱容量下降;通过增大耗尽层中的重掺杂浓度和结深,采用非均匀沟道掺杂及在光电二极管与FD节点之间加入P型注入层并增大浓度,可有效提高PPD电容抗质子辐照能力。A numerical simulation on the degradation of full well capacity of 4T CMOS active pixel image sensor caused by 10 MeV proton irradiation at different fluences of 0,1×10,3×10,5×10 and 1×10^(11) cm-2 is carried out.The structure of 4T CMOS image sensor model and proton irradiation-induced defect model with different fluences are established.Combined with the full well capacity calculation model,the effects of proton irradiation with different fluences on the capacitance of photodiode(PPD),TG channel barrier,and the depletion layer formed between floating node(FD)and substrate are analyzed,and the damage mechanism of irradiation induced full well capacity degradation is revealed;Based on the structure design of CMOS image sensor,an anti radiation design scheme is proposed.The results show that proton irradiation introduces a large number of oxide trap charges and interface states into the oxide layer,which widens the PPD depletion layer and decreases PPD.Proton irradiation produces positive oxide trapped charge in the oxide layer,resulting in induced negative charge at the Si-SiO_(2) interface of TG transmission gate channel,and the decrease of TG channel barrier and the increase of dark current,which indirectly leads to the decrease of full well capacity.By increasing the heavily doped concentration and junction depth in the depletion layer,using non-uniform channel doping and adding P-type injection layer between photodiode and FD node and increasing the concentration,the anti proton irradiation ability of PPD capacitor can be effectively improved.

关 键 词：4T CMOS图像传感器 质子辐照模拟 满阱容量 抗辐射设计 

分 类 号：TN386[电子电信—物理电子学]