Growth of bulk Si from Si–Al alloy by temperature gradient zone melting

Abstract

The continuous growth of bulk Si in the Si–Al alloy using the temperature gradient zone melting (TGZM) technique is an effective method to separate the primary Si from the eutectic structure in the Si–Al alloy and to remove the majority of impurities, such as metals, B and P elements during the alloy refining process. A Si source was used to maintain the Si concentration in the alloy melt and reduce the influence of the solute-transmitting process by temperature gradient due to the precipitation of the primary Si. Bulk Si could be obtained in the Si–Al alloy through the TGZM process. With the initial temperature of 1461K and temperature gradient of 1.81K/mm, the actual growth rate of the bulk Si was 0.000186mm/s. No inclusions and alloy phases were observed in the bulk Si. The removal rate of Fe impurity was 99.9% and the removal fraction of B, P and Al was 71.2%, 90.2%, 78.5% respectively.