Growth of multicrystalline silicon ingot with both enhanced quality and yield through quartz seeded method

An effective method for ingot quality control in directional solidification by using artificially designed quartz coating as seed is demonstrated in this paper. Quartz powders sprayed at the bottom of the crucible provided numerous nucleation points for the silicon grain growth. The quartz seeded growth ingot showed a large number of small and uniform silicon grains at the bottom, although the grain size increased with crystal growth. Comparatively less dislocation agglomerates and multiplication rate through bottom to top were observed through photoluminescence (PL) analysis. Crystals produced by quartz seeded method showed a higher and more uniform minority carrier lifetime distribution compared to that produced from normal method without seed, and shorter low lifetime area length at the bottom compared to that produced from mc-Si seed-assisted growth method, indicating larger production yield under the same feedstock charging weight. An enhanced average solar cell conversion efficiency of as high as 0.52% in absolute value was obtained compared to that made from seedless method under the same cell manufacture process line, very close to that made from mc-Si seed-assisted growth method.