The CMS development on Si detectors

Silicon microstrip detectors at LHC have to be operated in a very hostile environment. Few years ago CMS started a systematic study of the device characteristics as a function of the most important parameters. Investigations have been carried on different bulk resistivities, crystal orientation, high voltage stability as a function of the implant and metal strip geometry and of multiguard structures. Finally, charge collection efficiency and S/N ratio for different types of sensors have been studied in beam tests. (13 refs) .