Towards a new generation of Monolithic Active Pixel Sensors for LHC experiments

Monolithic active pixel sensors (MAPS) represent the third generation of semiconductor devices, on the path of silicon strip and hybrid pixel detectors, applied to the tracking of charged particles in High-Energy Physics experiments. By integrating the sensor and readout electronics on the same silicon die, MAPS enable high-granularity, low-material detectors with excellent performance in terms of track and vertex reconstruction. The ALICE collaboration at CERN has selected MAPS as the reference sensor technology for its tracking detector, the Inner Tracking System 2 (ITS2). The ALice PIxel DEtector (ALPIDE), based on the TowerJazz 180 nm CMOS imaging process, is the MAPS chip developed for the ITS2.At the end of the current Large Hadron Collider run, the ALICE tracking system will undergo an upgrade with the construction of a new inner barrel, denominated ITS3. The three innermost layers of the detector will be replaced with wafer-scale MAPS, thinned to 50 µm or less, and fabricated using the TPSCo 65 nm CMOS imaging process, identified as the reference technology for the next generation of monolithic sensors. The present research aims at the experimental characterization and simulation studies of the first test structures fabricated using the TPSCo 65 nm CMOS process for High-Energy Physics applications, demonstrating the feasibility and the adequacy of MAPS based on such a technology to meet the requirements of the ALICE tracking system upgrade. The obtained results are also highly promising in terms of radiation tolerance and fast timing capabilities, positioning MAPS as strong candidates for high precision time measurements in present and future particle collider experiments.