Influence of vertical temperature gradients on wafer quality and cell efficiency of Seed-assisted high-performance multi-crystalline silicon

The effect of vertical temperature gradients on the performance of Seed-assisted high-performance (HP) multi-crystalline silicon (mc-Si) is investigated by numerical simulations and contrast experiments. The vertical temperature gradients are designed by keeping the temperatures at the top and lowering the temperatures at the bottom. Two Seed-assisted HP mc-Si ingots were grown by means of a larger and a conventional vertical temperature gradient. It is found that the larger vertical temperature gradients result in the more parallel growth direction of grains and the longer crystal growth length, increases the percentages of <112> grain orientation and random grain boundaries, which are benefit for crystal quality. The experimental results also confirm that the wafer of ingot grown with a larger vertical gradient has the better quality, and their cell efficiency can increase.