Influence of oxygen precipitation on copper precipitation in Czochralski silicon

The influence of oxygen precipitation on copper precipitation in Czochralski silicon was investigated by means of defect etching, optical microscopy, and Fourier transform infrared spectrometer. It was found that the density, distribution, and morphology of copper precipitation can be influenced by oxygen precipitate sequence significantly. The spherelike copper precipitates uniformly distributed along the whole cross section were generated only in the specimens oxygen precipitation at the very beginning of the heating treatment. While in the specimens, copper precipitation firstly, the large star-like precipitate colonies was generated due to the repeated nucleation mechanism. Additionally, the bulk microdefects (BMDs) density of the latter was higher than the former. The influence of oxygen precipitation nuclei, which was formed during 750 °C for 8 h annealing, on copper precipitation was similar to that of oxygen precipitation, indicated that the initial density and distribution of oxygen precipitation nuclei were the main factors to decided copper precipitation.