Study of oxygen clustering in Czochralski silicon at 450 °C–800 °C: correlation with thermal donors formation

The understanding of the generation-annihilation phenomena of oxygen-related thermal donors (TDs) in p-type Czochralski silicon is of great importance for device fabrication and operation in microelectronic and photovoltaic industry. In this work, we report on oxygen clustering-based activation and partial annihilation of TDs in Cz-Si submitted to thermal annealing under nitrogen at 450 °C-800 °C for different thermal plateau exceeding 4 hours. The effect of thermal annealing on interstitial oxygen and dimer (O_i and O_2i) vibration modes appearing in the 580 cm^-1-500 cm^-1 spectral range is studied. We found that heat treatment at 450°C and 650 °C give rise to new thermal donors (NDs) that are located at 540 cm^-1 and 532 cm^-1, respectively. Subsequent to heat treatment above 650 °C, we depict the formation of new thermal oxygen defects having an IR signature in the 1800 cm^-1-1500 cm^-1 spectral range, and which are especially sensitive to the thermal treatment duration. Resistivity measurements confirm that several of them are electrically active. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)