Melting method of silicon using the float-zone melting

摘要

The invention relates to the production of silicon, for example, for the power microelectronics or the photoelectric industry including the manufacturing of solar cells. The invention solves the problem of obtaining silicon in the form of high-purity rods made of native silicon of varying quality and forms suitable by their electrical, mechanical and geometrical properties for growing single crystals of various purposes using the float-zone melting method. The proposed method, which implementation is shown on Fig. 1 and Fig. 2 , shall be realized as follows: silicon is putted into the container, having a thermal insulator (1) and the cooling device (2), and placed in the melting chamber of the apparatus, produce a vacuum and melt, using electron beams (3) for heating. In addition, beams are moved aside up to the specified diameter and start scanning, forming an annular heating zone. A heating zone diameter (5) selected in a way to obtain the required result - to melt down all silicon in container or to maintain part of the initial not melted mass (7) between the molten zone (6) and the walls of the container. After melting of particular part of initial mass (7), the crystal seed (8) is inserted into the container, coupled with a melt and grow the rod (9) of required diameter. The growing process is managed by changing the stretching speed (V) and a heating intensity (3), besides is kept at a constant heating (3) the annular zone (4) diameter. Focal spot scanning path (5) by electron beams together form a shape that is close to the required diameter of the ring and form sufficient heat symmetry field, in order to obtain the cylindrical rod (9).