EFFECTS OF ENERGY DEPOSITION BY NUCLEAR-SCATTERING IN SILICON P-I-N-DIODE DETECTORS

The changes in thick (similar to 300 mu m) and thin (15 mu m) Si p-i-n diode detectors that take place as a result of alpha particle and Cu- 63(5+) ion irradiation have been studied by Deep Level Transient Spect roscopy (DLTS) and by monitoring the reverse-bias leakage currents. A linear increase in reverse-bias current with alpha-particle dose was o bserved that could be at tributed to the formation of vacancy-associat ed defects (divacancy, A- and E-centres). Damage within the active lay er of the device, characterised by the increase in leakage current per unit active volume, together with literature pion, proton and heavy i on data, exhibited a linear dependence on the energy deposited in nucl ear processes over many orders of magnitude. Annealing at temperatures of 150 degrees C for 4 h (vacuum bakeout) resulted in a reduction in leakage current and the size of the DLTS peaks became smaller. This te mperature is much lower than expected for removal of divacancies, sugg esting that recovery of the reverse bias current is mediated by other defect centres. (C) 1998 Elsevier Science B.V.