Thermal history effect on the nucleation of oxygen precipitates in germanium doped Cz-silicon studied by high-energy X-ray diffraction

Abstract

The oxygen (O) precipitate growth kinetics from moderate and high germanium (Ge) doped Czochralski-growth silicon (Cz-Si) are in-situ investigated at 1000°C utilizing high-energy X-ray diffraction and analyzed with respect to precipitate density within a diffusion-driven growth model. Distinct different precipitation kinetics are observed for high Ge doped specimens. From the comparison of three thermal treatments, it was found that even for a high Ge concentration the nucleation rate at 800°C is not influenced, however it facilitates larger grown-in precipitates of smaller amount as compared to the precipitates in undoped and moderately Ge doped samples. However, those grown-in O precipitates can be erased either by a direct annealing at 1200°C or 1000°C, but on the other hand stabilized by an annealing step at 800°C, which in this manner asa drift step of grown-in precipitates for the high Ge-doped samples. In comparison additional nuclei are formed at 800°C in the moderate and undoped cases.