TCAD modeling of bulk and surface radiation damage effects in silicon devices

Future frontier accelerators envision the use of silicon sensors in environments with fluences exceeding 1 × 10^17 1 MeV n_eq/cm^2. Presently available silicon sensors can operate efficiently up to fluences of the order of 10^16 1 MeV n_eq/cm^2. Therefore, novel sensors and readout electronics must be developed. Within this framework, state-of-the-art Technology CAD (TCAD) tools can be proficiently used to account for both bulk and surface radiation-induced damage effects in semiconductor sensors, fostering design optimization and enabling a predictive insight into the electrical behaviour of novel solid-state detectors. In particular, the balance between extending already developed models and methodologies or devising different approaches should be carefully considered. In this contribution, the different available TCAD numerical models addressing bulk and surface radiation damage effects will be illustrated. It will also be shown how these models have been used for the optimization of devices, particularly 3D sensors and Low Gain Avalanche Diodes. Moreover, extending the applicability of these models to extreme fluence scenarios requires carefully accounting for the modeling of acceptor and donor removal, impact ionization, carrier mobility and lifetime, and trap dynamics.