Enhancing guard-ring protection structures for the next generation of radiation-hard thin silicon particle detectors

Future hadron collider experiments (e.g. FCC-hh) will require highly efficient silicon particle detectors able to operate in extremely harsh radiation environments (∼10^17 1 MeV n_eq/cm^2). The guard-ring (GR) protection structures are an essential part of the sensor. They have to sustain a large external bias with minimal leakage current injection into the core region, making their design and optimisation crucial, especially when using thin sensor substrates. In the framework of the “eXFlu-innova” research project (AIDAinnova), different GR optimisation studies for both p- and n-type thin substrates (ranging from 15 to 55μm) have been conducted up to high fluences (above 10^15 1 MeV n_eq/cm^2). These studies have been made possible thanks to ad-hoc Technology CAD (TCAD) modelling of various GR design strategies, accounting for comprehensive bulk and surface radiation-induced damage effects. Moreover, an extensive test campaign on such GR structures has been performed, both before and after irradiation. Leveraging the recently obtained agreement between simulated and experimental data for p-type substrates, both before and after irradiation, the validated development framework was extended to simulate GR design options for n-type substrates as well. This contribution provides a summary of the GR optimisation studies for both p- and n-type substrates and their impact on performance.