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

doi:10.3952/physics.v53i4.2763

E. Gaubas
D. Bajarūnas
T. Čeponis
D. Meškauskaitė
J. Pavlov

DOI: https://doi.org/10.3952/physics.v53i4.2763

Keywords: C-DLTS, I-DLTS, O-I-DLTS, Si particle detectors, neutron irradiation

Abstract

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.