Predicting material parameters for intrinsic point defect diffusion in Silicon Crystal Growth

The incorporation of intrinsic point defects into a growing crystal and their subsequent agglomeration into larger defects are controlled by the solidification and subsequent cooling process. The evolution of intrinsic point defects in Silicon can generally be described by a system of reaction-diffusion equations for the concentration of selfinterstitials and vacancies. The main difficulty in quantitative intrinsic point defect prediction with such an approach is the uncertainty of the temperature-dependent material properties. These properties are generally unknown. This is due to the difficulty to measure them experimentally at high temperatures. To circumvent this problem these properties can be computed by an underlying microscopic model by means of molecular dynamics simulations. A potential due to Stillinger and Weber or, alternatively, a many-body potential due to Tersoff is applied for this purpose. The calculated material data for these potentials as well as intrinsic defect concentrations during the Czochralski growth of silicon are presented. A transient process simulation with varying process conditions is performed and the influence on the intrinsic defect concentrations in the crystal is shown.