Development of advanced 3D silicon radiation detectors

To enable more precise measurements of the Higgs boson and to search for physics beyond the Standard Model, the Large Hadron Collider (LHC) will soon undergo an upgrade, entering the High-Luminosity LHC (HL-LHC) era. In the meanwhile, the High Energy Physics (HEP) community is already exploring potential successors to the HL-LHC, such as the Future Circular Collider (FCC), aiming to study new physics at even higher energy scales. Experiments at these colliders, however, require sensors in the innermost layers of the detectors to withstand unprecedented levels of radiation damage. Owing to their inherent radiation hardness, small-pitch 3D pixel sensors have been chosen to equip the innermost tracking layers for the upgrade of both the ATLAS and CMS experiments at the HL-LHC. Moreover, 3D-trench electrode sensors from the TimeSPOT batch have shown outstanding timing resolution after a fluence of $1 \times 10^{17} n_{eq}/cm^{2}$, paving the way for 4D tracking in future experiments (e.g., FCC). Despite excellent results obtained from different flavors of 3D sensors, it is possible to further improve their performances and fabrication yield from the perspective of process and layout optimization. With the help of TCAD simulations, this work primary focuses on enhancing the radiation hardness of small-pitch 3D pixel sensors by leveraging different isolation technologies and electrode geometries. Additionally, Monte-Carlo simulations within the Allpix$^2$ framework have been performed to assess the feasibility of various 3D sensors for 4D tracking in future HEP experiments.