Impact of the initial growth interface on the grain structure in HPMC-Si ingot

In High Performance Multi-Crystalline-Silicon (HPMC-Si) ingots, small seed grains generate grain boundaries that can terminate the propagation of dislocation clusters. Here, we focus on the seed template formation and its impact on the initial growth by directional solidification utilizing metallography, photoluminescence, and EBSD analysis. In the seed region, two randomly oriented grain morphologies are found: a genuine non-melted seed from the poly-Si chunks, and a re-solidified infiltrated molten silicon region. All grains grow by epitaxy on the seed grains and grains grown from wider grains in the seed, reach a higher solidification height.