Investigation Of The Effect Of Electron Irradiated Defects In Czochralski Silicon

The point defects were mainly generated in electron irradiated Czochralski Silicon (CZ-Si). These defects were interacted in the process of annealing, which had great influence on the electrics performance and oxgen precipitation in CZ-Si. In this paper the influence of electron irradiation on the electrics performance and the irradiation defects in CZ-Si were investigated with Hall Effect, Four-Point Probe Measurement, Fourier Transform Infrared Absorption Spectrometer (FTIR) and Position Annihilation Spectrum (PAS).Oxygen concentration in the electron-irradiated samples was decreased and proportional to electron doses. Two infrared absorption bands at 830cm-1 and 860cm-1 were exhibited the same thermal stability via the annealing temperature lower than 300℃. It was considered that these two peaks should have different charge states, due to neutral VO (VO0) pairs and negatively charged VO (VO-) pairs, respectively. With annealing temperature increase, transformation of VO into VO2 occurred. The results showed that the resistivity increased and the minority carrier lifes decreased in electron irradiated CZ-Si, which due to the irradiated defects can capture free carriers. It was considered that irradiation defects presented donor state which led the resistivity to decline in electron irradiated samples annealed at 750℃. Pre-annealing at low temperature can provide nucleus as precursors which promoted the generation of new donors in the next heat treatment at 750℃.It was also found that an enhanced precipitation among electron irradiated samples appeared as a transient process, which had not been observed at high temperature 1150℃. The effect of rapid thermal process (RTP) conditions on bulk microdefects (BMDs) and denuded zone (DZ) was investigated. DZ width decreased with RTP temperature and cooling rate increasing.