Neutron irradiation induced displacement damage effects on CMOS active pixel image sensor

Displacement damage effects due to neutron irradiations of CMOS active pixel sensors manufactured by a 0.5 m CMOS N-Well technology are presented through the analysis of the dark signals behavior in pixel arrays. When the fluence of neutron reached the predetermined point, the changes of dark signal, dark signal non-uniformity, saturated output signal and pixel unit output signal were measured off line. Experiment shows that the mean dark signals and the dark signals, non-uniformity increased dramatically with the increasing neutron fluence. Saturation output signal voltage did not degrade obviously even at the highest fluence. It is concluded that a great deal of inhomogeneous defect energy levels occur between pixels irradiated by neutrons, which enhances the dark signals. In addition, individual pixel unit test pins are introduced from the sample chip, and the output signal of the pixel unit is tested under different integration time.