Growth of low-cost and high-quality monocrystalline silicon ingots by using split recycled seeds

Abstract

In this work, we proposed a new method of seed recycling for casting monocrystalline silicon ingots. Different regions at the bottom of the monocrystalline silicon bricks were cut for controlling its size and crystal defects, which were used as recycled seeds and reasonable splicing to induce grain boundaries. The results showed that the recycled seeds with higher concentration of metal impurities will result in a longer red zone and the yield of mono-Si ingot would be slightly decreased. The defect density in the recycled seeds increased significantly, but decreased greatly during the seeding and growth. The defect distribution in PL images at the top of ingots grown with recycled seeds was similar to that of ingots grown with new seeds. Furthermore, the average cell efficiency of the solar cells fabricated by the wafers grown with recycled seeds was only 0.1% different from that of the wafers grown with new seeds. Therefore, this low-cost seed recycling method is of great significance for reducing the cost of cast monocrystalline silicon.