Clusters of Defects as a Possible Origin of Random Telegraph Signal in Imager Devices: a DFT based Study

The origin of the random telegraph signal (RTS) observed in semiconductors-based electronic devices is still subject to debates. In this work, by means of atomistic simulations, typical clusters of defects as could be obtained after irradiation or implantation are studied as a possible cause for RTS. It is shown that:(i)a cluster of defects is highly metastable,(ii)it introduces several electronic states in the band gap,(iii)it has an electronic cross section much higher than the one of point defects.These three points can simultaneously explain why an electron-hole generation rate can switch with time, while respecting the experimental measurement.