An approach to obtain the pinch-off voltage of 4-T pixel in CMOS image sensor

An approach to obtain the pinch-off voltage of 4-T pixel in CMOS image sensor is presented.This new approach is based on the assumption that the photon shot noise in image signal is impacted by a potential well structure change of pixel.Experimental results show the measured pineh-off voltage is consistent with theoretical prediction.This technique provides an experimental method to assist the optimization of pixel design in both the photodiode structure and fabrication process for the 4-T CMOS image sensor.