Depletion depth studies with the MALTA2 sensor, a depleted monolithic active pixel sensor

MALTA2 is a depleted monolithic active pixel sensor (DMAPS) developed in the Tower 180 nm CMOS imaging process. Monolithic CMOS sensors offer advantages over current hybrid imaging sensors both in terms of increased tracking performance due to lower material budget but also in terms of ease of integration and construction costs due to the monolithic design. Current research and development efforts are aimed towards radiation-hard designs up to 100 Mrad in Total Ionizing Dose and 3×1015 1 MeV neq/cm2 in Non-Ionizing Energy Loss. One important property of a sensor's radiation hardness is the depletion depth at which efficient charge collection is achieved via drift movement. Grazing angle test-beam data was taken during the 2023 SPS CERN test beam with the MALTA telescope and Edge Transient Current Technique studies were performed at DESY in order to develop a quantitative study of the depletion depth for un-irradiated, epitaxial MALTA2 samples. The study is planned to be extended for irradiated and Czochralski MALTA2 samples.