Multiguard structures for high-voltage operation of radiation-damaged silicon detectors

High-voltage operation is a solution to fully collect the charge on heavily radiation-damaged p+-n silicon detectors. Multiguard structures can limit the occurrence of critical fields and enhance the breakdown voltage of a p+-n junction. In this work we present the result of the testing of some devices available in 8 different designs before and after irradiation with ionising and non-ionising radiation sources. The effect of both surface and bulk damage will be considered, for different radiation doses. Various experimental techniques have been used, like DC and AC electrical characterisation and Light Emission Microscopy. A simulation work will also be presented to obtain an optimised design on the basis of the experimental results.