Comparative study of < 111 > and < 100 > crystals and capacitance measurements on Si strip detectors in CMS

For the construction of the silicon microstrip detectors for the Tracker of the CMS experiment, two different substrate choices were investigated. A high-resistivity (6 k Omega cm) substrate with (111) crystal orientation and a low-resistivity (2 k Omega cm) one with (100) crystal orientation. The interstrip and backplane capacitances mere measured before and after the exposure to radiation in a range of strip pitches from 60 mu m to 240 mu m and for values of the width-over-pitch ratio between 0.1 and 0.5.