高帧频高灵敏度线列PIN-CMOS图像传感器研究

Study on High Frame and High Sensitivity for Linear PIN-CMOS Image Sensors

设计了一款高帧频高灵敏度双通道16元线列PIN-CMOS图像传感器。相对于传统的pn结光电二极管,PIN光电二极管具有结电容小和量子效率高的优点,可以降低CTIA像素电路的噪声,提高信噪比;同时采用一种新型的相关双采样电路结构,可以在边积分边读出的模式下实现相关双采样,抑制像素复位带来的KTC噪声。基于0.35μm PIN-CMOS工艺进行了线列CMOS图像传感器流片,并对器件的光电性能进行了测试。测试结果表明:在像元尺寸为90μm×90μm,700nm波长下,器件灵敏度达3 000V/(lx·s),量子效率为96%;在40kHz高帧频、0.05lx光照条件下器件信噪比为7,适于弱信号下的高速探测。

The CMOS image sensor integrated with high frame rate and high sensitivity pin photodiode array was designed.Compared with p-n photodiode,p-i-n photodiode presents the advantages of small junction capacitance and high quantum efficiency.In order to promote the signal-to-noise ratio,the sensor implements a new correlated double sampling(CDS)circuit for eliminating KTC noise while working in the integration during reading mode.In this paper,linear CMOS Image sensor based on CTIA pixel circuit was implemented in 0.35μm PIN-CMOS process,and the photoelectric response of the device was tested and evaluated.The results show that sensitivity is 3 000 V/(lx·s),and quantum efficiency is 96% at 700 nm wavelength.At a frame rate of 40 kHz,the signal-to-noise is 7 with the illumination down to 0.05 lx,which is suitable for high-speed detection under weak light signal.