热处理对背照式CMOS传感器信噪比影响的实验研究

基于真空光电阴极和背照式CMOS图像传感器研制了电子轰击CMOS(EBCMOS)混合型光电探测器.为了对BSI-CMOS图像传感器在EBCMOS混合型光电探测器领域的应用提供可靠性指导,对BSI-CMOS图像传感器进行了100℃～325℃的变温热处理实验,着重分析了热处理后的BSI-CMOS图像传感器的光响应输出信号值、固定模式噪声(fixed pattern noise,FPN)、随机噪声及信噪比(signal-to-noise ration,SNR)随热处理温度的变化规律.实验结果表明:随着热处理温度的升高,样品器件的光响应输出信号值基本保持不变,当温度升高至325℃时,样品器件的固定模式噪声由32 e-升高至246 e-,随机噪声由51 e-升高至70 e-,信噪比由17.76 dB降低至4.81 dB,其中信噪比的降低主要归因于固定模式噪声的增大,热处理温度达到325℃会导致BSI-CMOS图像传感器信噪比明显降低.

Impact of Annealing Temperature on SNR in Backside-illuminated CMOS Image Sensor: an Experimental Study

We present an electron bombarded CMOS (EBCMOS) detector by combining the technology of vacuum photocathodes and backside-illuminated CMOS (BSI-CMOS) image sensors. To provide a reliable guidance for an EBCMOS application of a BSI-CMOS image sensor, annealing temperature effects on the BSI-CMOS image sensor from 100℃ to 325℃ are presented. The effects of annealing temperature on output photo response signals, fixed pattern noise, temporal noise, and signal-to-noise ratio(SNR) of the BSI-CMOS image sensor were investigated. Experimental results show that the output photo response signals of the sensor remained unchanged, fixed pattern noise increased from 32 e to 246 e , temporal noise increased from 51 e to 70 e , and the SNR decreased from 17.76 dB to 4.81 dB with an increase in annealing temperature from 300℃ to 325℃. The decreases in SNR could be attributed to the increase in the fixed pattern noise with annealing temperature increase from 300℃ to 325℃.