Influence of temperature gradient at interface on defect multiplication in seed-assisted multicrystalline silicon

Abstract

The control of defect multiplication in the upper part of seed-assisted multicrystalline silicon (SAMC-Si), also called as high-performance multi-crystalline silicon, has become crucial for the further improvement of multicrystalline silicon (mc-Si) crystal quality. This work investigates the impact of the temperature gradient at solid/liquid interface on the defect multiplication and solar cell performance. To get the in-time temperature gradient at solid/liquid interface, an equation and an experiment method were developed. It is found that the multiplication rate at the upper ingot is strongly relevant to the temperature gradient at solid/liquid interface. After modifying the temperature gradient, the defect density in the upper part of ingot is reduced about 40%, and the solar cell efficiency increases averagely about 0.07%. Finally, the mechanism and control of defect multiplication were discussed.