Random Telegraph Signal in Monolithic Active Pixel Sensors

CMOS Monolithic Active Pixel Sensors (MAPS) technology allows integrating very small sensing elements with a pixel pitch of similar to 10 mu m together with analogue and digital signal processing circuits into a monolithic chip, which may be thinned down to a thickness of similar to 50 mu m. These features make MAPS an interesting technology for a broad range of applications in charged particle tracking. Intense R&D was performed in the last years in order reach the necessary radiation hardness. In the context of these studies, radiation induced Random Telegraph Signal (RTS) was found to introduce a substantial amount of accidental (noise) hits. In this work, we present a first systematic investigation of the rate of these fake hits as function of environmental conditions like accumulated radiation dose and temperature. Moreover, strategies to reduce the impact of RTS are studied.