Multicrystalline silicon assisted by polycrystalline silicon slabs as seeds

An effective method of using polycrystalline silicon (poly-Si) planar slabs as seed materials for industrial low-cost and high-quality seed-assisted multicrystalline silicon has been presented. The interspace volume of the poly-Si slab seed layer is much lower compared to poly-Si nugget seed layer, so the initial grains of the slab-assisted ingot are much more uniform than those of the nugget-assisted ingot. Photoluminescence (PL) and minority lifetime measurements showed a considerable reduction in dislocation cluster density in the slab-assisted ingot, especially at the middle and top regions. The average cell efficiency based on the slab-assisted ingot is enhanced by 0.12% in absolute value compared to the nugget-assisted ingot. Moreover, the bottom edge of slab-assisted ingot can be fully recycled through existing cleaning process without remaining SiC particles, which saves considerable materials and slicing costs in mass manufacturing compared to nugget-assisted growth method.