A CMOS image sensor with dual pixel reset voltage for high accuracy ultraviolet light absorption spectral imaging

In this paper, we report a CMOS image sensor (CIS) with dual pixel reset voltage and high sensitivity to ultraviolet (UV) light for high SNR UV light absorption spectral imaging. The dual pixel reset voltage was introduced in order to improve the accuracy of absorption imaging by suppressing the fixed pattern noise due to the threshold voltage (Vth) variation. The developed CIS exhibited 71 dB SNR, 15 Me^- full well capacity and high quantum efficiency to UV light. As an application of the developed CIS, the diffusion of sub-ppm concentration ozonated water into ultrapure water (UPW) was successfully visualized under the 254 nm light waveband.