IR studies of oxygen-related and carbon-related defects in Sn-doped silicon

The ability of tin (Sn) to capture vacancies in silicon material attracts considerable interest in relation with electronic applications where radiation hardness is necessary. In this sense the full knowledge of the behavior of radiation-induced defects in Sn-doped Si is particularly important. The present report gives a systematic study of the evolution of the vacancy-oxygen (VO_n, 1≤ n≤ 6) defects and the carbon-oxygen (C_iO_i) defect in electron-irradiated Sn-doped Cz-Si containing carbon. The radiation-induced defects and their reactions were investigated by Infrared Spectroscopy (IR) in the course of 20 min isochronal anneals from room temperature up to ∼750 °C. Interestingly, in Sn-doped Cz-Si samples we were able to monitor and study IR bands correlated with VO₅/VO₆ defects. In particular, we tentatively attributed two bands at 1037, 1051 cm^-1 to the VO₅ defect, and two other bands at 967, 1005 cm^-1 to the VO₆ defect. Concerning carbon-related defects, our results show that the disappearance of the 862 cm^-1 band of the C_iO_idefect is accompanied in the spectra by the emergence of a band at 1048 cm^-1 previously correlated with a C_sO_2i structure. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)