Numerical study of surface waves generated by low frequency EM field for silicon refinement

Abstract

One of the most perspective methods to produce solar grade silicon is refinement via metallurgical route. The most critical part of this route is refinement from boron and phosphorus due to high segregation coefficients. One possible approach to remove boron is use of reactive gas on surface of silicon melt. An approach of creating surface waves on silicon melt’s surface is proposed in order to enlarge its area and accelerate removal of boron via chemical reactions. This paper focuses on numerical analysis of surface wave creation by means of low frequency magnetic field. Frequency of magnetic field and its amplitude significantly change the character of surface waves with most changes occurring when waves become nonlinear. Mechanism of impurity removal from silicon surface to the gaseous phase is directly connected with surface area enlargement. It was found that two effects are responsible for enhancement of refinement rate – enlargement of surface area and wave-assisted diffusion close to the surface of silicon.