Complexes defects induced by neutron irradiation of Cz-silicon

The boron-doped Cz-Si was irradiated with 1 MeV neutrons delivered by the Es-Salam reactor at two different neutron fluence values, 1.98 × 1018 and 3.96 × 1018 n/cm2, respectively. Annealing processes were carried out under argon atmosphere, at 550 °C and 950 °C for 60 min, respectively. The effects of isochronal annealing on the neutron-irradiated silicon’s IR absorption spectrum are presented. The obtained results indicate two forms of the Near-Edge Absorption that increase with increasing neutron fluence. One centered at 1000–1500 nm (NEA-1) and second near 1600–1800 nm (NEA-2). After the annealing process at 550 °C, the IR absorption spectrum shows the change of the first Near-Edge Absorption band towards a shorter wavelength at 1000–1200 nm range as well as the disappearance of the (NEA-2) band near 1800 nm. The appearance of the lithium impurity associated with divacancy at 1700 nm that confirms the transmutation of boron into lithium of the samples. At 950 °C, the experimental data show that 1700 nm which is associated with Li divacancy persists for higher neutron fluence, but not for lower fluence.