Development in a Novel CMOS Process for Depleted Monolithic Active Pixel Sensors

Recent advancements in CMOS technologies enable Depleted Monolithic Active Pixel Sensor (DMAPS) realizations by exploiting high resistivity and/or high voltage biasing to deplete a large active sensing volume. DMAPS have emerged as a promising alternative for particle detection in high energy physics due to their low cost, reduced manufacturing complexity and high granularity. In the framework of the ALICE Inner Tracking System (ITS) upgrade, prototype sensors have been designed and characterized in the TowerJazz 180nm standard CMOS imaging process and in a novel modification of this process to achieve full depletion. Measurement results demonstrate that the sensors manufactured using the modified process are fully functional even after a dose of $10^{15}n_{eq}/cm^2$, which is the expected NIEL of the outer layers of the ATLAS Inner Tracker (ITk) during the future High Luminosity Large Hardon Collider (HL-LHC) operation. Based on these encouraging results, two highly granular, low power DMAPS chips with different readout architectures have been designed and are being proposed for the ATLAS ITk upgrade.