Investigation Of The Irradiation Defects And Electrics Performance In Fast Neutron Irradiated Czochralski Silicon

In this paper the influence of neutron irradiation on the electrics performance and the irradiation defects in Czochralski silicon were investigated with Hall effect, Four-Point Probe measurement, Fourier Transform Infrared Spectrometer (FTIR) and Position Annihilation Spectrum (PAS).The results show that the acceptor abounds in the irradiated silicon and two types of acceptors will form in the irradiated silicon after annealing at 450℃ or 600℃, respectively. Those acceptors had great influence on the intensity of the current carrier. The amount and the generation rate of the thermal donor will be depressed too after preheating treatment at 650℃. While rapid thermal process (RTP) at 1200℃ with N₂ atmosphere the amount of the dornal will be depressed in irradiated silicon but with Ar atmosphere is the unirradiated silicon.In the neutron-irradiated low-oxygen-Si the chains of vacancies are formed during annealing at 250℃ and accounts for the disappearance of FTIR absorption peak at 2759cm^-1. Increase the annealing temperature larger three-dimensional vacancy clusters will appearing and the signal of the PAS will be disappeared. In the neutron irradiated CZ-Si the annealing of divacancies is suggested to recombination with Oi or VO to form V₂O and V₃O. The delay of the annealing out of V₂ singal in PAS than FTIR due to V₃O has the same position lifetime with V₂.After annealing at 200℃ the VO began to eliminate, in varied neutron irradiated silicon the annihilation process of VO was different: Oi and V will be traped be VO in low and high dose neutron irradiated silicon, respectively.In the low neutron irradiated CZ-Si two infrared absorption bands at 919.6cm^-1 and 1006cm^-1 were abserved. Appearance and disappearance of those infrared absorption bands together with 889cm^-1(VO₂). The two vibrational bands are assigned to the configuration of O-V-0 that a VO trapped in the next neighbor position to an Oi atom. Prolong the annealing time from one hour up to ten hours at 300℃ or increase the annealing temperature up to 400℃ for one hour the metastable defect (O-V-O) will convert into VO₂. In the high dose (10¹⁹) neutron irradiated CZ-Si the formation of the VO₂ will be depressed.