Analysis of Total Dose-Induced Dark Current in CMOS Image Sensors From Interface State and Trapped Charge Density Measurements
Analysis of Total Dose-Induced Dark Current in CMOS Image Sensors From Interface State and Trapped Charge Density Measurements
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DOI：
10.1109/tns.2010.2077653
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发表时间：
2010-11
影响因子：
1.8
通讯作者：
V. Goiffon;C. Virmontois;P. Magnan;S. Girard;P. Paillet
中科院分区：
文献类型：
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作者：
V. Goiffon;C. Virmontois;P. Magnan;S. Girard;P. Paillet
通过比较CMOS图像传感器中暗电流测量结果与界面态密度和陷阱电荷密度测量结果，研究了总电离剂量引起的CMOS图像传感器暗电流的来源。采用0.18 μ mCMOS图像传感器工艺制作了两种类型的光电二极管和几种厚氧化物场效应管，并在3 krad ~ 1 Mrad的10 keV X射线下曝光。结果表明，辐射诱导的陷阱电荷扩展了氧化物界面处的空间电荷区，导致界面态SRH产生电流的增强。等时退火测试表明，STI界面态在低于100°C的温度下退火，而在300°C下30分钟后仍保留约三分之一的捕获电荷。
The origin of total ionizing dose induced dark current in CMOS image sensors is investigated by comparing dark current measurements to interface state density and trapped charge density measurements. Two types of photodiode and several thick-oxide-FETs were manufactured using a 0.18-μm CMOS image sensor process and exposed to 10-keV X-ray from 3 krad to 1 Mrad. It is shown that the radiation induced trapped charge extends the space charge region at the oxide interface, leading to an enhancement of interface state SRH generation current. Isochronal annealing tests show that STI interface states anneal out at temperature lower than 100°C whereas about a third of the trapped charge remains after 30 min at 300°C.