Displacement Damage induced in 150 nm CMOS SPADs by 2 MeV electrons

This work investigates the degradation induced to 150 nm CMOS Single-Photon Avalanche Diodes (SPADs) by 2 MeV electrons. Radiation-induced damage effects are investigated through a Dark Count Rate (DCR) analysis. Different architectures of CMOS SPADs are tested. Displacement Damage results in lattice defects that lead to a DCR increase mostly due to thermal contributions in most linear-region operating devices. The study reveals an interesting behavior of DCR as a function of both the absorbed dose and the applied voltage. This suggests a strong tunneling contribution to radiation-induced noise, alongside the thermal one, in a peculiar way for Geiger-mode devices such as SPADs