Morphology of Oxygen Precipitates in RTA Pre-treated Czochralski Silicon Wafers Investigated by FTIR Spectroscopy and STEM

摘要

The influence of RTA pre-treatments at 1250 ℃ on the morphology and stoichiometry of oxygen precipitates was investigated by STEM and FTIR. The morphology of the oxygen precipitates depends on the temperature of the subsequent annealing. Annealing at 800 ℃ results first of all in the formation of 3D dendritic precipitates while during annealing at 900 ℃or 1000 ℃ mainly plate-like and octahedral precipitates are formed. The absorption bands of the dendritic SiO_x precipitates were identified and simulated based on effective medium theory. All regular plate-like and octahedral precipitates could be well fitted assuming x=2.