Radiation hard DMAPS pixel sensors in 150 nm CMOS technology for operation at LHC

Abstract

Monolithic Active Pixel Sensors (MAPS) have been developed since the late\n1990s employing silicon substrate with a thin epitaxial layer in which\ndeposited charge is collected by disordered diffusion rather than by drift in\nan electric field. As a consequence the signal is small and slow, and the\nradiation tolerance is below the requirements for LHC experiments by factors of\n100 to 1000. We developed fully depleted (D)MAPS pixel sensors employing a 150\nnm CMOS technology and using a high resistivity substrate as well as a high\nbiasing voltage. The development has been carried out in three subsequent\niterations, from prototypes to a large pixel matrix comprising a complete\nreadout architecture suitable for LHC operation. Full CMOS electronics is\nembedded in large deep n-wells which at the same time serve as collection nodes\n(large electrode design). The devices have been intensively characterized\nbefore and after irradiation employing lab tests as well as particle beams. The\ndevices can cope with particle rates seen by the innermost pixel detectors of\nthe LHC pp-experiments or as seen by the outer pixel layers of the planned\nHL-LHC upgrade. They are radiation hard to particle fluences of at least\n$10^{15}~\\mathrm{n_{eq}/cm^2}$ and total ionization doses of at least 50 Mrad.\n