温度对4管像素结构CMOS图像传感器性能参数的影响

Temperature Effects on Performance Parameters in 4T CMOS Image Sensor

为了对4管像素结构CMOS图像传感器的空间应用提供可靠性指导,对4管像素结构的CMOS图像传感器进行了-40~80℃的变温实验,着重分析了样品器件的转换增益、满阱容量、饱和输出和暗电流等参数随温度的变化规律。实验结果表明,随着温度的升高,样品器件的转换增益从0.026 54 DN/e下降到0.023 79 DN/e,饱和输出从4 030 DN下降到3 396 DN,并且暗电流从22.9 e·pixel-1·s-1增长到649 e·pixel-1·s-1。其中器件转换增益的减小应主要归因于载流子迁移率随温度升高而下降使得像素后端读出电路增益降低;饱和输出的降低则是因为转换增益的降低,因为转换增益随温度变化对饱和输出的影响要大于满阱容量随温度变化对饱和输出的影响。

In order to provide a reliable guidance for the spatial application of the 4T CMOS image sensor, temperature effects on 4T active pixel sensor CMOS image sensor from -40 ℃ to 80 ℃ were presented. The influences of temperature on conversion gain, full well charge, saturated output and dark current of the device were investigated. The experiment results show that the conversion gain of device decreases from 0.026 54 DN/e to 0.023 79 DN/e, the saturated output decreases from 4 030 DN to 3 396 DN, and the dark current increases from 22.9 e·pixel-1·s-1 to 649 e·pixel-1·s-1 with the temperature increasing. The decrease of conversion gain should be attributed to the decrease of the carrier mobility with the temperature increasing. The decrease of saturation output is mainly because of the decrease of the conversion gain which the influence of the conversion gain on saturated output is greater than that of the full well capacity with the change of temperature.