DEFECT DISTRIBUTIONS IN MEV ION-BOMBARDED SILICON

High purity, low doped silicon has been irradiated with low fluences of 1.3 MeV protons, 5.0 MeV alpha particles, 24.0 MeV oxygen, and 38.4 MeV sulphur ions. These bombardments give rise to various point defects that have been investigated by deep level transient spectroscopy. We have studied the distributions of three previously well documented defects (the vacancy-oxygen (VO) pair, positioned 0.18 eV below the conduction band edge, the divacancy with two levels at 0.23 and 0.42 eV below the conduction band and an oxygen-carbon related complex positioned 0.34 eV above the valence band maximum) for a constant value of deposited elastic energy for the different primary ions. The results show that heavier ions are less efficient in producing stable defects and that the VO-pair is more abundant in low mass ion irradiated silicon compared to the other two defects.