TID effects in deep N-well CMOS monolithic active pixel sensors

This paper is devoted to the study of total ionizing dose effects in deep N-well (DNW) CMOS monolithic active pixel sensors (MAPS) for particle tracking fabricated in an STMicroelectronics 130 nm process. DNW-MAPS samples were exposed to γ-rays up to a final dose of 1100 krad(SiO₂) and then subjected to a 100°C annealing cycle. The origins of degradation in charge sensitivity and equivalent noise charge are discussed based on the results from radiation hardness characterization of single transistors belonging to the same CMOS technology and of test diodes reproducing the MAPS collecting electrode structure. Also circuit simulations have been performed to supply further evidence for the proposed degradation mechanisms.