TEM characterisation of high pressure–high-temperature-treated Czochralski silicon samples

Pieces taken out of high oxygen content (cO>1018 cm−3) Czochralski-grown Si wafers have been preannealed at different conditions in order to generate nucleation centres for oxygen precipitation and large oxygen-related defects. Next, the samples have been treated at temperatures up to 1620 K under various hydrostatic pressures (up to 1 GPa) in Ar atmosphere in order to investigate the effect of uniform stress on the defect structure, type and density as a function of the applied pressure–temperature treatment. Transmission electron microscopy results indicate that for treatment temperatures below 1400 K, the size of the extended defects increases with the applied pressure, while their density diminishes. However, for higher treatment temperatures, the overall density of defects is much smaller and the behaviour is the opposite; the density of defects increases with pressure. The results will be discussed as a function of the preannealing of the samples and of the treatment conditions employed, and will be compared with the data given by infrared spectroscopy.