Investigation Of Oxygen Precipitation And Induced-Defects In Fast Neutron Irradiated Czochralski Silicon

In this paper, the effects of irradiation doses and annealing conditions on oxygen precipitation and induced defects in fast neutron irradiated Czochralski silicon (CZSi) were studied using Fourier Transform Infrared Absorption Spectrometer (FTIR), optical microscope and transmission electron microscopy(TEM).At room temperature, the absorption band attributed to interstitial oxygen broadened due to the generation of oxygen precipitates. At low temperature, the broadened range split to peaks that attributed to spherical oxygen precipitates and octahedral oxygen precipitates, respectively. The peak, which attributed to the platelet oxygen precipitates appeared, too.Stacking fault, dislocation and dislocation loop appeared in fast neutron irradiated CZSi after annealing at high temperature. The stacking fault and the dislocation are induced by oxygen precipitation. The dislocation loop generates from the irradiation-induced defects. Increasing annealing time, the stacking faults grew and generated. The etching pattern of dislocation loop consisted of several dislocation lines. While with increasing annealing time it changed into semicircular. With increasing annealing time, the density of defects increases. Polyhedral oxygen precipitate was observed by TEM and the ratio of oxygen atoms to silicon atoms was 1.5.Rapid thermal process (RTP) was first used in the intrinsic gettering (IG) process of fast neutron irradiated CZSi. The effects of RTP conditions on bulk microdefects (BMDs) and denuded zone (DZ) was investigated. RTP didn't change the process of oxygen precipitation and the behavior of the irradiated samples was different from the non-irradiation samples for the vacancy type defects induced by fast neutron irradiation. With increasing RTP temperature, DZ width decreased. DZ formed in the sample that annealed in nitrogen atmosphere.