Suppress of dislocations induced by feedstocks weight in cast-mono crystalline silicon

Abstract

Dislocation clusters are the most harmful defects in cast-mono crystalline silicon (CM-Si). This work focused on an important source of which, the stress introduced by parasitic weight of raw silicon feedstocks. The impacts of indentation morphology and dopants on dislocation generation and mobilization are studied systematically. A G2 CM-Si ingot with intelligent doping strategy has been grown with or without buffer layer for characterization comparably. It is found that Ga-doping seeds could significantly suppress dislocation generation and movement in the seeds owing to the high Peierls energy and pinning effect of impurity atoms. Besides, the buffer layer can efficiently weaken the generation of dislocation in the ingots ascribed to the decreased stress by widening the indentation area. These results pave a new way to fabricate high-quality CM-Si ingots with low dislocation density for photovoltaic application.