Investigations on the Behaviour of Carbon during Inductive Melting of Multicrystalline Silicon

Abstract

The influence of the CO concentration in the gas phase on the distribution of carbon in Bridgman-grown, multicrystalline silicon is studied. The growth experiments were conducted in a high-vacuum induction furnace either under a CO enriched atmosphere or under CO free conditions. Furthermore, thermodynamic calculations in the system silicon/oxygen/carbon were done. In crystal growth under a CO enriched atmosphere a SiC-containing layer is formed on the top surface of the melt in agreement with the calculated phase diagram. In this case, the level of substitutional carbon in the cystal was found to be almost constant, whereas the axial carbon concentration in crystals grown under CO free conditions increases monotonously according to Scheil's law.

The effect of graphite components and crucible coating on the behaviour of carbon and oxygen in multicrystalline silicon

“…Obviously, the carbon level in the melt is pinned by the SiC layer at the surface as already mentioned in Ref. [15]. In contrast, a pronounced axial macrosegregation profile was found in crystals grown under CO free conditions (series B).…”

“…A detailed description of the furnace is given in Ref. [15]. It should be noted that this setup allows for the directional solidification from a well-mixed melt because the induced Lorentz force associated with inductive heating causes a relatively intense melt flow.…”

“…Reaction (1) describes a parasitic coating of the furnace interior remote from the Si melt, which is typically observed in mc-Si growth [10]. Reaction (4) is of more importance for crystal growers, because it implies the formation of a SiC layer onto the melt surface, which influences the carbon level in the melt directly [15]. Table. 1).…”

“…[15]. Here we present a more detailed and extended study that includes the behaviour of oxygen and SiO in the system.…”

Novel combination of orientation measurements and transmission microscopy for experimental determination of grain boundary miller indices in silicon and other semiconductors

“…This paper presents a method to determine grain boundary orientation of straight boundary segments, which works in most kinds of semiconductors. Straight grain boundaries exist over several cm heights of multicrystalline ingots (Raabe et al ., 2009). No transmission electron microscope (TEM) investigation is needed to achieve a reduction of experimental effort.…”