Damage-induced surface effects in silicon detectors

One of the main applications of silicon detectors in future collider experiments is their use in the tracking area. In addition to the very intense hadron flux (both neutral and charged) causing bulk damage, a severe effect by ionizing radiation has also to be envisioned at small radii. In the present study results obtained after irradiation with low energetic electrons (20 keV) are presented. In this case bulk damage can be completely excluded. Effects on the oxide charge and density of interface states are characterized by C—V and I—V measurements. In addition the corresponding changes of the space charge region are observed with a scanning proton micro beam. The electric field distribution, the depletion depth and the lateral extension of the depletion region is thus investigated and the results are compared with detailed simulations using the ToSCA-program.