Study of Dislocation Generation and Growth Orientations in Upgraded Metallurgical Grade Multicrystalline Silicon

Abstract

We used high-purity multicrystalline silicon prepared by metallurgical method for the study of directional solidification. The optical microscope was used to observe the etch pits on the surface of silicon wafers, and we calculated their dislocation density. The result showed the space distribution of dislocation density presented “V” shape for each ingot produced at different drop-down rates. The dislocation density of slicon ingots followed the order 10<20<30<40μm/s. The high-resolution glow discharge mass spectroscopy was used to analyze the concentration of transition metal impurities. The macro-morphology of vertical-section of silicon ingots growth at different drop-down rates was observed. The x-ray diffraction measurement was performed to analyze the crystallographic orientations of the silicon ingot growth at 20μm/s, which was a better drop-down rate for producing high-quality multicrystalline silicon.