CMOS Pixel Development for the ATLAS Experiment at HL-LHC

The high luminosity upgrade of the LHC necessitates a complete exchange of the current ATLAS Inner Tracker for a purely silicon one. Large areas therefore have to be covered by radiation tolerant, low cost and low material budget silicon detectors. New approaches are being explored using CMOS pixel sensors, providing charge collection in a depleted layer. They are based on technologies that allow to use high depletion voltages and high resistivity wafers for large depletion depths with multiple nested wells, enabling for CMOS electronics to be embedded safely into the sensor substrate. We are investigating depleted CMOS pixel detectors with monolithic or hybrid designs in view of their suitability for high trigger rates, fast timing and the high radiation environment at HL-LHC. This paper will discuss recent results of the main candidate technologies and the current developments towards a monolithic solution.