Analysis of microcrystal formation in DS-silicon ingot

作者：Zhang ZhiQiang^*; Huang Qiang; Huang ZhenFei; Li BiWu; Chen Xue

来源：Science China Technological Sciences, 2011, 54(6): 1475-1480.

DOI：10.1007/s11431-010-4271-2

• polycrystalline silicon ingot
• microcrystal
• G/V
• melt convection
• solidification interface shape

The DS (directional solidification) polycrystalline silicon ingot is the most important photovoltaic material today, and the conversion efficiency of solar cells is affected by the morphology and organization of the crystal. Uniform grains with larger size are conducive to get high-quality wafer, so improving the cell conversion efficiency. However, grains sizes that are less than 1 mm(2) can be observed frequently in the central district of mc-Si ingots, which bring negative effect to the quality of the mc-Si ingot and decrease the electrical performance of wafer. In this paper, we make an attempt to explain the formation mechanism and influence factors of microcrystal in mc-Si ingot with computer simulation technology and theory of component supercooling. It was found that: to avoid production of microcrystal, it's better to increase the value of G/V (V is the growth rate and G is the near-interface temperature gradient), strengthen the melt convection front in the solidification interface and keep a fairly flat solid/melt interface in producing mc-Si ingot.

• 出版日期2011-6