STUDY OF THE EFFECTS OF NEUTRON-IRRADIATION ON SILICON STRIP DETECTORS

Silicon strip detectors and test structures were exposed to neutron fluences up to PHI = 6.1 x 10(14) n/cm2, using the ISIS neutron source at the Rutherford Appleton Laboratory (UK). In this paper we report some of our results concerning the effects of displacement damage, with a comparison of devices made of silicon of different resistivity. The various samples exposed showed a very similar dependence of the leakage current on the fluence received. We studied the change of effective doping concentration, and observed a behaviour suggesting the onset of type inversion at a fluence of approximately 2.0 x 10(13) n/cm2, a value which depends on the initial doping concentration. The linear increase of the depletion voltage for fluences higher than the inversion point could eventually determine the maximum fluence tolerable by silicon detectors.