A TEM study of SiC particles and filaments precipitated in multicrystalline Si for solar cells

The microstructure of SiC particles and SiC filament-type precipitates found in block-cast multicrystalline Si was studied in detail by transmission electron microscopy (TEM). TEM investigations showed that the SiC particles are single crystalline and the SiC filaments are microcrystalline. Both types of precipitates consist of cubic SiC. However, a high density of planar defects was found in the filaments. Very wavy and rough interface between SiC filaments and silicon (Si) was revealed by high-resolution TEM. In addition, SiC filaments do not show a special orientation relationship with respect to the Si matrix. The growth mechanisms of SiC precipitates are discussed. Finally, the influence of SiC inclusions in terms of device performance is considered.