Monolithic Pixel Development in 180 nm CMOS for the Outer Pixel Layers in the ATLAS Experiment

The ATLAS experiment at CERN plans to upgrade its Inner Tracking System for the High-Luminosity LHC in 2026. After the ALPIDE monolithic sensor for the ALICE ITS was successfully implemented in a 180 nm CMOS Imaging Sensor technology, the process was modified to combine full sensor depletion with a low sensor capacitance ($approx$ 2.5fF), for increased radiation tolerance and low analog power consumption. Efficiency and charge collection time were measured with comparisons before and after irradiation. This paper summarises the measurements and the ATLAS-specific development towards full-reticle size CMOS sensors and modules in this modified technology.