Study of oxygen transport in Czochralski growth of silicon

The present status and special features of experimental analysis and numerical modelling of oxygen transport in the Czochralski growth of silicon is treated. The solubility of oxygen in liquid Si is discussed in detail as this parameter is used as a boundary condition (oxygen source) in the numerical process models. The possibility of in situ measurement of the oxygen distribution in the melt in dependence from boundary conditions by using an electrochemical sensor is shown. Model conceptions for a numerical simulation of the oxygen transport in Czochralski melts are discussed in detail. The problem of boundary layer resolution is analysed, examples how to solve it are given. A quantitative modelling of the oxygen transport suffers at present from the fact that the existing turbulence models are not adequate to predict the velocity field precisely enough. (C) 1999 Elsevier Science B.V. All rights reserved.