The upgrade of the ATLAS tracking detector for the High-Luminosity Large Hadron Collider at CERN requires the development of novel radiation hard silicon sensor technologies. For the development of depleted CMOS sensors for ATLAS we combined small electrodes with minimal capacitance and advanced processing for fully depleted active sensor volume to achieve radiation hard CMOS sensors in line with ATLAS ITk specifications.
Based on initial studies on the prototype sensor "TowerJazz Investigator" we have now developed, produced and tested a first full-size depleted CMOS sensor based on the 180nm TowerJazz imaging process, the so-called "MALTA" sensor. The sensor combines special low-noise/low power front-end using small electrodes with a novel high-speed asynchronous readout architecture to cope with the high hit-rates expected at HL-LHC. The sensor has been produced end of 2017 and initial measurements have been carried out assessing its analog and digital performance. The poster will show efficiency studies performed with the TowerJazz Investigator chip at the CERN SPS test beam facility in 2017 and first measurement results with the new "MALTA" sensor.