Effects of energy deposition by nuclear scattering in silicon p-i-n diode detectors

Abstract

The changes in thick (∼300 μm) and thin (15 μm) Si p-i-n diode detectors that take place as a result of alpha particle and 63Cu 5+ ion irradiation have been studied by Deep Level Transient Spectroscopy (DLTS) and by monitoring the reverse-bias leakage currents. A linear increase in reverse-bias current with α-particle dose was observed that could be attributed to the formation of vacancy-associated defects (divacancy, A- and E-centres). Damage within the active layer of the device, characterised by the increase in leakage current per unit active volume, together with literature pion, proton and heavy ion data, exhibited a linear dependence on the energy deposited in nuclear processes over many orders of magnitude. Annealing at temperatures of 150°C for 4 h (vacuum bakeout) resulted in a reduction in leakage current and the size of the DLTS peaks became smaller. This temperature is much lower than expected for removal of divacancies, suggesting that recovery of the reverse bias current is mediated by other defect centres.