Vergleich relevanter Parameter von Multipixelsensoren für Spurdetektoren nach Bestrahlung mit hohen Proton- und Neutronflüssen

The further increase of the luminosity of the Large Hadron Collider ( LHC ) at CERN requires new sensors for the tracking detector of the Compact Muon Soleniod ( CMS ) experiment. These sensors must be more radiation hard and of a finer granularity to lower the occupancy. In addition the new sensor modules must have a lower material budget and have to be self triggering. Sensor prototypes, the so called “ MPix ”-sensors, produced on different materials were investigated for their radiation hardness. These sensors were fully charac- terized before and after irradiation. Of particular interest was the comparison of different bias methods, different materials and the influence of various geometries. The degeneration rate differs for the different sensor materials. The increase of the dark current of Float-Zone-Silicon is stronger for thicker sensors and less than for Magnetic-Czochralski-Silicon sensors. Both tested bias structures are damaged by the irradiation. The poly silicon resis- tance increases after irradiation by fifty percent. The Punch-Through-Structure is more effected by irradiation. The punch-through voltage increase by a factor of two. Due to the higher pixel current, the working point of the sensor is shifted to smaller differential resistances