Multi-guard ring TCAD simulations for different n-on-p planar silicon particle detectors

Abstract

This work presents a comparative study between three multi-guard ring structures that could be suitable for n-on-p silicon particle detectors for high luminosity applications. One multi-guard structure has p-type guard rings while the others have n-type guard rings with p-stop/p-spray isolation between n+ implants. The performance of the unirradiated structures are studied by increasing the fixed oxide charge density from 5 × 10+10 to 1 × 10+12 cm−2. It's found that for two structures there is a value of oxide charge density for which the breakdown voltage is maximum while for the third structure the breakdown voltage increases with oxide charge density. The performance of the irradiated structures are evaluated with simulations up to a radiation fluence of 1 × 10+16 1 MeV neutron equivalent/cm2/year (neq/cm2) using a three trap bulk radiation model for p-type silicon substrate. Structure with n-type guard rings and p-stop isolation exhibits low leakage current and good isolation between implants while structure with p-type guard rings shows higher breakdown voltage. The breakdown voltage is enhanced by adding floating metal field plates. TCAD simulation has been used to simulate current-voltage characteristics, electron and hole concentration profiles, and electric field and potential distributions.