Study of breakdown effects in silicon multi-guard structures

Many applications of silicon p⁺-n junctions as detectors require high voltage operation. In particular the LHC experiments, because of the radiation damage level, need very high bias working voltage to fully collect the ionising generated charge multi-guard structures can be used in order to improve the breakdown voltage of microstrip detectors, limiting the occurrence of critical fields in the proximities of a reverse biased p⁺-n junction. In this work we present results for different designs of multi-guard structures, before and after irradiation with ionising and non-ionising radiation sources (p,n,γ), and for different doses. Various experimental techniques have been used, like DC and AC electrical characterizations, and light emission microscopy. Moreover, a simulation work is presented. Its purpose is to improve the design on the basis of the experimental results