High-resolution photo-induced transient spectroscopy was used to investigate defect centers in n-type epitaxial Si after 24GeV/c proton irradiation with fluences of 3 x 1014 and 9 x 1014/cm2 followed by long-term annealing at 80C. The measurements revealed 9 traps with activation energies ranging from 5 to 460meV. In the material irradiated with the lower fluence the concentration of V2O−/0 complexes was found to be approximately 4 times lower than that of divacancies V2−/0. After the irradiation with the higher fluence the material defect structure was different and the concentration of V2O−/0 complexes was around 6 times higher compared to that of divacancies V2−/0.

Effect of Proton Fluence on Point Defect Formation in Epitaxial Silicon for Radiation Detectors. R.Kozłowski, P.Kamiński, E.Nossarzewska-Orłowska, E.Fretwurst, G.Lindström, M.Pawłowski: Nuclear Instruments and Methods in Physics Research Section A, 2005, 552[1-2], 71-6