PL and DLTS analysis of carbon-related centers in irradiated p-type Cz-Si

Photoluminescence (PL) and deep level transient spectroscopy (DLTS) have been used to investigate carbon related defects in p-type Cz-Si induced by proton irradiation. The interstitial carbon interstitial oxygen (CiOi) level in DLTS and the corresponding C-line (789.5 meV) in PL spectra are detected in as irradiated samples. Formations of the so-called P-line at 767 meV in PL and a new defect level at about 0.39 eV above the valence band edge, E-v, in the DLTS spectra are observed in the annealed samples. The evolution of the CiOi and E-v+0.39 eV levels in DLTS and also the C- and P- lines in PL upon post irradiation heat treatment is investigated, showing that the intensity of the CiOi level decreases with heat-treatment, which is consistent with the PL data for the C-line. The intensity of the E-v+0.39 eV level is enhanced and then saturates with annealing duration. We tentatively assign this level to the interstitial carbon oxygen dimer (CiO2i).