Influence of oxygen and carbon on the generation and annihilation of radiation defects in silicon

The influence of oxygen and carbon on the generation and annihilation of radiation defects in silicon is studied by deep level transient spectroscopy (DLTS), correlated with photoluminescence (PL) analyses. N+p silicon diodes with interstitial oxygen content between 1016 cm−3 and 1018 cm−3 and carbon content below 1016 cm−3, are irradiated by 2 MeV electrons with fluences ranging from 5 × 1014 cm−2 to 1016 cm−2. The DLTS spectra reveal two hole traps characterised by an activation energy of respectively 0.19 eV and 0.36 eV. Correlation with PL measurements confirmed the association of the 0.36 eV level with a CiOi and/or CiCs complex. Isothermal anneals performed at 200 °C resulted in a gradual conversion of the Ev + 0.19eV to a defect level at Ev + 0.24eV. From the oxygen content dependence of the transformation it is suggested that the divacancy diffuses and is trapped by interstitial oxygen forming a V2O complex.