CMOS image sensors (CIS) play a crucial role in the imaging industry. CIS produces low-quality images in low-light conditions. Single Photon Avalanche Diode (SPAD) is a device used for low-light imaging because of its ability to detect single photons of light. To detect a single light photon, SPAD is biased above its breakdown voltage (Gieger mode). When the photon hits the active area during Geiger mode, a significant reverse current (avalanche current) is observed.