Analysis of TSC spectra measured on silicon pad detectors after exposure to fast neutrons

We present thermally stimulated current (TSC) spectra measured on asymmetric p-n-junctions fabricated from detector grade silicon. A multitude of characteristic deep levels generated by fast neutron-induced damage with fluences ranging from 1012 to 1014 cm−2 were observed. The TSC spectra were found to depend strongly on both the filling conditions and the electric field strength in the device. The filling of the deep levels has been investigated in detail by varying the current, temperature, and duration of the free carrier injection pulse. The corresponding observations in conjunction with a delayed heating analysis allow a tentative identification of the complex defects VOi, CiOi, CiCs, and the divacancy VV.