Simulation of irradiation-induced surface effects in silicon detectors

In future high-luminosity collider experiments, fine segmented silicon strip and pixel detectors will be used for tracking very close to the interaction point. Therefore the surface effects due to irradiation are very important for the long term performance of these devices. A good understanding of these effects is the basis for the development of less radiation sensitive detectors. An important tool for this understanding is device simulation. In the comparison of device simulations with measurements of ionisation-induced surface effects it became obvious that the electric field distribution in the passivation during the irradiation cuases a position dependent increase of interface charges. In order to achieve more realistic simulations this was taken into account by varying the oxide charge density according to results obtained from MOS-structures.