OXYGEN-TRANSPORT ANALYSIS IN CZOCHRALSKI SILICON MELT BY CONSIDERING THE OXYGEN EVAPORATION FROM THE MELT SURFACE

Oxygen transport analysis of silicon melt in a silica crucible by considering the oxygen evaporation from the free surface was performed. The oxygen concentration stays in the region of 10(15)-10(16) atoms/cm(3) along the free surface and it strongly depends on the vertical flow under the free surface. It has been found that the oxygen distribution along the free surface affects the oxygen concentration in wafers obtained from grown crystals. The suction and the sweeping out flows at the peripheral region of the crystal are formed beneath the periphery of the crystal, and these oscillatory flows determine the oxygen concentration at the periphery of the crystal. Present results yielded good agreement with the experimental results of the radial oxygen distribution in grown crystals. Thus we established the method for prediction of the oxygen concentration in silicon crystal using the oxygen concentration conditions based on the experimental results for the free surface.