The deteriorated area of the multicrystalline silicon (mc-Si) ingots grown by directional solidification, commonly known as the Red Zone, is usually removed before wafering. This area, characterized by poor minority carrier lifetime, is located on the sides, at the top, and the bottom of the mc-Si ingots. In this study, the effect of internal gettering by oxygen precipitates and structural defects has been investigated on the bottom zone of a mc-Si ingot. Nucleation and growth of oxygen precipitates as well as low temperature annealing were studied. Photoluminescence imaging, lifetime mapping, and interstitial iron measurements performed by μ-PCD reveal a considerable reduction of the bottom Red Zone. An improvement of lifetime from below 1 µs to about 20 µs and a reduction of interstitial iron concentration from 1.32 × 1013 at/cm3 to 8.4 × 1010 at/cm3 are demonstrated in this paper.
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机译：通常在晶圆加工之前将因定向凝固而生长的多晶硅（mc-Si）晶锭的劣化区域（通常称为红色区域）去除。该区域的特征在于少数载流子寿命较差，位于mc-Si锭的侧面，顶部和底部。在这项研究中，已经研究了在mc-Si晶锭底部区域的氧沉淀和结构缺陷对内部吸气的影响。研究了氧沉淀物的成核和生长以及低温退火。由μ-PCD执行的光致发光成像，寿命映射和间隙铁测量表明，底部红色区域显着减小。本文证明了将寿命从低于1µs改善到大约20µs，并将间隙铁浓度从1.32×1013 at / cm3降低到8.4×1010 at / cm3。
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