Long-Term Degradation Study of CMOS SPADs in Space Radiation Environment

We investigated the radiation tolerance of a Single-Photon Avalanche Diode (SPAD) device manufactured using a 150-nm CMOS process. CMOS SPADs have been studied in view of utilization as photo-detectors in future space missions. An irradiation campaign has been carried out on several test chips containing SPAD arrays with different dimensions. Samples have been exposed to different displacement damage dose. The dark count rate (DCR) characterization as a function of the delivered proton fluence has showed a significant increase in mean DCR, providing the limits of operability of such devices in a space environment. Annealing and cooling have been investigated as possible damage mitigation approaches.