New results on silicon microstrip detectors of CMS tracker

Interstrip and backplane capacitances on silicon microstrip detectors with p(+) strip on n substrate of 320 mu m thickness were measured for pitches b etween 60 and 240 mu m and width over pitch ratios between 0.13 and 0.5. Pa rametrisations of capacitance w.r.t. pitch and width were compared with dat a. The detectors were measured before and after being irradiated to a fluen ce of 4 x 10(14) protons/cm(2) of 24 GeV/e momentum. The effect of the crys tal orientation of the silicon has been found to have a relevant influence on the surface radiation damage, favouring the choice of a [1 0 0] substrat e. Working at high bias (up to 500 V in CMS) might be critical for the stab ility of detector, for a small width over pitch ratio. The influence of hav ing a metal strip larger than the p(+) implant has been studied and found t o enhance the stability. (C) 2000 Elsevier Science B.V. All rights reserved .