Impact of harsh radiation on metal-overhang equipped sensors in the LHC environment

The utility of silicon microstrip detectors in future high luminosity colliders, like LHC requires some serious issues concerning radiation hardness to be carefully considered. The performance of metal-overhang (MO) equipped Si micro-strip sensors has been studied after irradiation for the preshower detector to be used in CMS experiment at LHC, CERN. The parameterization of these effects has been performed using Hamburg model to simulate the operation scenario of MO equipped sensors over 10 years of LHC operation. The utility of overhanging metal extension as junction termination technique after type-inversion has been explored for the first time in this work Several interesting results like a shift in the optimal oxide thickness in MO equipped structures after irradiation have been reported. It has been found that the breakdown performance of the device actually improves after irradiation due to the beneficial effect of type-inversion. Dielectric and semi-insulator passivated MO equipped structures have been compared after irradiation in this study. Also, the impact of various crucial geometrical parameters like device depth (W_N), width of back N+ layer used for ohmic contact (W_N⁺) and width of overhang extension (W_MO) on the metal-overhang equipped structure after type-inversion has been presented in detail.