Investigation of stoichiometry of oxygen precipitates in Czochralski silicon wafers by means of EDX, EELS and FTIR spectroscopy

In this work, we used EDX, EELS and FTIR spectroscopy to investigate the stoichiometry of oxygen precipitates in Czochralski silicon wafers. The EDX analysis of a plate-like precipitate demonstrated that the composition of the precipitate is SiO1.93. This result was confirmed by EELS where the characteristic plasmon peak of SiO2 was observed. Additionally, the absorption band of plate-like precipitates at 1223 cm−1 was found in the FTIR spectrum measured at liquid helium temperature. It was demonstrated that this band can only be simulated by the dielectric constants of amorphous SiO2.