Anomalous Oxygen Precipitation in Czochralski Silicon

The effect of curvature of the liquid-solid interface of the Czochralski silicon crystal on microdefect occurrence is examined via the crystal's oxygen precipitation behavior. Curved interface regions were found to contain more microdefects than the flat-interfaced regions. Annealing results at high and low-high temperatures show that oxygen precipitation is dominated by heterogeneous nucleation at a high temperature (1050C) without a prior low temperature nucleation treatment. Therefore, oxygen precipitation in crystals lacking grown-in microdefects would be retarded.