Optically induced current deep level spectroscopy of radiation defects in neutron irradiated Si pad detectors

  • E. Gaubas
  • D. Bajarūnas
  • T. Čeponis
  • D. Meškauskaitė
  • J. Pavlov
Keywords: C-DLTS, I-DLTS, O-I-DLTS, Si particle detectors, neutron irradiation


Identification of the prevailing radiation defects of large density remains a considerable issue for particle detectors made of high resistivity Si. To clarify the dominant radiation induced traps within CERN standard Si pad detectors, the capacitance (C-) and current (I-) deep level transient spectroscopy (DLTS) techniques have been combined. Additionally, the optical (O-) injection I-DLTS regime has been employed to cover a wide range of neutron irradiation fluences of 1012–1016  cm–2. The spectra of C-DLTS and O-I-DLTS have been recorded using the temperature scans in the range of 20–300 K. The radiation induced vacancy (V) attributed defects such as V-O, V2, and clusters have been identified, the density of which increases with irradiation fluence in the range of 1012–1014 cm–2, while this density saturates for the collected neutron fluence of more than 1014 cm–2.